THE HENRYS OF MANCHESTER Sixth Grove Lecture W. V. Farrar, BSc, PhD, and Kathleen R. Farrar, BSc, PhD Dept of History of Science and Technology, UMIST, Manchestei I E. L. Scott, MSc Stamford High School, Stamford, Lincs Thomas Henry’s early life Manchester life in the late 1700s 40 . . .. .. . . . . . . 35 . . .. . . . . . . 37 Henry’s magnesia . . * . .. . . .. . . . . . . William Henry . . .. . . . . .. . . . . .. 42 Later generations . . . . . . .. . . . . . . . . 45 Most history is about great men, and the history of science is no exception. Lavoisier, Dalton, Berthollet, Berzelius, set the course of 19th century chemistry; we know and we write a lot about such people, because they are very important. But let us think of the other side of the coin-of the people whose courses were set by the great men, the scientists of second rank, the ‘common scientists’.It is these people, after all, who do 99 per cent of all science, who carry on the daily business of science. They teach, they work in industry, they write textbooks; they do their bits of research which once in a lifetime may touch greatness-or may not. The Henry family of Manchester were such ‘common scientists’, and we have found them a very rewarding study. They did all the things just mentioned, and ran medical practices as well; one of them, William Henry, just touched the edge of fame with ‘Henry’s law’ about the solubility of gases. They were all in contact with a great man, John Dalton, who owed to them more than he ever admitted, or perhaps even knew.They fit very well T. S . Eliot’s lines about J. Alfred Prufrock: No, I am not Prince Hamlet nor was meant to be. Am an attendant lord, one that will do To swell a progress, start a scene or two Advise the prince. .. THOMAS HENRY’S EARLY LIFE Thomas Henry was born in Wrexham, the son of a dancing-master. Now one would not have thought that a dancing-master in 18th century Wrexham would make a very fat living; but his father intended to send Thomas to Oxford, and then into the Church. There is in fact a little mystery about Thomas’s father, and we have a suspicion (it is no more) that he may have been a natural son of Lord Bulkeley, who ruled Anglesey almost like an independent kingdom. Farrar, Farrar and Scott 35 W i I liam (? I 700- I 774) Thomas (I 734- I8 16) Ellis (1743-1815) I C William (1774-1836) Peter ( 1769- I 808) Thomas (I 767- 1798) I William Charles (18044892) I I Simplified family tree of the Henry family.Only male members who lived t o maturit) are shown. However this may be, there was enough money to think of sending Thomas ta the University, and it is said that a horse had even been hired to take him there; but at the last minute the family got cold feet ‘with the uncertainty of eventual success’. The horse was sent back to the stables and the disappointed boy apprenticed to a local apothecary. Halfway through his time, Thomas’s master died, and he finished his apprenticeship over the border at Knutsford in Cheshire.In either Wrexham or Knutsford his interest in chemistry was aroused, improbable though it may seem, by reading the Latin text of Boer- haave’s Elementae chemiue, a book which, as his son said, ‘was not calculated to present the science in its most fascinating aspect’. But it is difficult to think of a better education that he could have had in chemistry in those days; Boerhaave and the apothecary’s shop-no university could have taught him more. R.I.C. Reviews 36 When he was about 20, Thomas left Knutsford to become assistant to a leading apothecary of Oxford. Two important things happened to him there. His master’s practice lay among University men, and he met some of his old schoolfellows from Wrexham Grammar School, who were friendly towards him, and enabled him to continue his education in an informal fashion.Secondly, he became acquainted with another apothecary, Samuel Glass, who made magnesium carbonate for medicinal purposes; we shall hear more of him later. After a few years at Oxford, Thomas declined an offer of a partner- ship, went back to Knutsford, started his own apothecary’s business and married a relative of his former master. He must have prospered, for in 1764 he bought a practice in fashionable St Ann’s Square, Manchester-and this is where the story really begins. Manchester in 1764 was a mere country town (pop. 17000). Its almost explosive growth had barely begun; but its growth and its wealth were such that an able (and personable) young apothecary could not fail to prosper, and Thomas practised very profitably for nearly 50 years.Unlike most men in such a position, however, he did not rest content with professional success and a growing family; he soon began to extend his energies in other directions-into industrial ventures, original work in chemistry, and the educational and intellectual life of Manchester. William Henry (left), father of Thomas Henry, shown above as a young man. MANCHESTER LIFE IN THE LATE 1700s To deal with the last matter first, at some time in the 1770s Thomas Henry left the Established Church, and became a Unitarian. This was a large, influential, wealthy (but rather unpopular) sect ifi Manchester at that time, which wor- Farrar, Farrar and Scott 37 shipped at Cross Street Chapel.This religious dissent, coupled with his interest in science, brought Thomas on to the fringe of the Lunar Society, aninformal group of experimenters and speculators centred in the Birmingham area, and on the personality of Matthew Boulton, Watt’s partner. He became friendly with many of the ‘Lunaticks’ including Priestley (on whose recommendation he became FRS in 1775), James Watt and his son (also called James), and Josiah Wedgwood the potter. Manchester at that time must have held as many men of real intellectual distinction as London itself. There was Thomas Percival, Charles White, John Ferriar, all with an honourable place in the history of medicine; the mathe- matician Henry Clarke, the Unitarian minister Thomas Barnes, wealthy gentlemen of wide interests like T.B. Bayley; and also industrialists con- sciously seeking a scientific basis for their craft-Thomas Henry himself, John Wilson the dyer, Thomas Cooper the bleacher, later James Watt junior (who came to work in Manchester) and the Scottish engineer Peter Ewart. Many of these, but not all, were Unitarians; many, again not all, radical or even republican in politics, with admiration for the recent American revolution. It seems that a number of these people, with the example of the Lunar Society in mind, began to meet in each other’s houses of an evening, to hear or read a paper on some scientific or philosophical topic. But unlike the Lunar Society, which did not outlive its founders, the Manchester group felt the need of some formal and permanent organization; this was formed in 1781 as the Manchester Literary and Philosophical Society (the ‘Lit and Phil’), with regular meetings in a room at the back of Cross Street Chapel.Percival was president, and he, Barnes, and Thomas Henry were the real moving spirits. In 38 R.I.C. Reviews spite of the heavy Unitarian and Radical bias among its members, the Society was anxious not to be identified in the public mind with religious or political faction; religion and politics were forbidden topics of discussion. It was of course into this congenial gathering of dissenting scientists who left their political views at the door, that John Dalton was received when he came to Manchester in 1793.Thomas Henry’s first paper read to the Lit and Phil was ‘An essay on the consistency of literary and philosophical interests with commercial pursuits’- a plea for a ‘liberal’ education for the sons of a mercantile and manufacturing community. Barnes also spoke to the same effect, and in 1783 the Lit and Phil tried to put its ideals into practice by founding the Manchester College of Arts and Sciences, in which Thomas Henry lectured on chemistry, dyeing, and bleaching. This institution, with its evening lectures to young artisans, fore- shadowed in many respects the Mechanics’ Institutes of the 1820s. Perhaps it came before its time, for its life was short; the last advertisements appeared in the Manchester newspapers in the autumn of 1787. One account of its decline was that it was due to ‘a superstitious dread of the tendency of science to unfit young men for the ordinary details of business’ ; but Thomas Henry himself, in a letter written at the time, had no doubt that ‘bigotry and political rage’ was the cause.The College, in fact, split the Lit and Phil into two factions, and led to wholesale resignations. Above and left: Manchester in the late 1700s. The College should not be confused (though it often is) with the Manchester Academy, founded in 1786 by the same group of people, with Barnes as Principal. This was a Dissenting Academy of the ordinary kind, largely residential, a direct successor to Warrington Academy which had foundered a Farrar, Farrar arid Scott 39 short time before.This was the Academy at which Dalton taught; Thomas Henry and his son, Thomas junior, continued their chemical lectures in it until young Thomas went to America in 1794. This time the Lit and Phil were a t great pains to dissociate themselves from the Academy, by a public dis- claimer in the newspapers. About Thomas Henry’s research work I shall not say much, because it was of no lasting importance. He, and indeed all the Henrys, were concerned with the chemistry of gases-pneumatic chemistry. Thomas was maturing as a chemist just at the time when there was a dawning realization that there were different gases; different chemical individuals, not just bad air, and good air, and air with a smell; and he was interested in working out some of the implications of this fascinating new idea.‘Fixed air’ (COz) was the most avail- able of the gases, and he and Percival did some experiments on the effect of COZ on the growth of plants which might, in more expert hands, have led them to an understanding of photosynthesis; but they missed it, and the success went to Priestley and Ingenhousz. There was also his enthusiasm for pneumatic medicine; these new gases would be a means of introducing chemi- cal substances into the body through the lungs, and this might have interesting medical consequences. Indeed, in the (lucky) hands of Humphry Davy, it led a little later to the discovery of the effects of nitrous oxide, though not, curiously, to the discovery of anaesthesia. But we suspect that Henry only made his unfortunate patients cough and splutter.Thomas Henry was not a great scientist, nor even a good one. He was an enthusiastic amateur, with an incurable optimism about what science could do, and a burning ambition to spread a knowledge of science all through the com- munity, especially to people working in industry, from mill-owner to artisan. This he shared with his colleagues in the Lit and Phil (and with revolutionary France); and he and his friends prepared the ground in Manchester for the next generation, the real professionals-his son William, and John Dalton. HENRY’S MAGNESIA We cannot leave Thomas Henry without saying a little about the source of the family’s wealth; the magnesia factory. The 18th century, whatever else it may have been, was the great century of overeating, and indigestion powders were the best-selling lines in the apothecary’s shop.You can ease the pangs of stomach acidity by taking chalk, but this causes constipation; soon after 1700 a new (at first secret) remedy was found in magnesium carbonate, which neutra- lizes acidity effectively and is also a mild laxative. Among the people who made magnesium carbonate for sale was the apothecary Samuel Glass, who had a little factory on Cowley Marsh, on the outskirts of Oxford, when Thomas Henry was there as a young man. Thomas later said himself, with devastating candour, how he had lived in the neighbourhood of ‘a gentleman . . . celebrated as the preparer of the most genuine magnesia.. . never having been able myself to make magnesia comparable to his. . . I was desirous of gaining some intelligence as to his process; and was at last so fortunate as to obtain some useful hints’. With the ‘hints’ obtained from Mr Glass, whether with that gentleman’s R. I. C. Reviews 40 knowledge or not, Henry began the production of magnesia in Manchester in 1772. However, the next year, with typical 18th-century rancour, he put out a pamphlet entitled Strictures on Glass’s magnesia, alleging that not only did the 4 oz bottles contain a mere l i o z , but that the contents ‘so puffed in every newspaper’ contained a great deal of chalk. This, as Henry no doubt intended, started a battle of pamphlets between himself and the successors to Glass (Glass probably being dead by this time).Much learned-sounding abuse was flung by both sides; but the interesting thing is this-Henry knew instinctively what he meant by a pure substance. His opponents, who were not chemists, did not. The concepts of ‘chemical purity’ and ‘chemical individuality’ are absolutely basic to the development of chemistry, and it is fascinating to see them being hammered out on the anvil of a minor commercial squabble. At first, Henry, like Glass, made magnesium carbonate. But soon he found that the oxide was an even more satisfactory product. It was more effective on a weight basis, and caused no distressing evolution of gas on contact with stomach acid. He also found (and this, kept a close secret, was the only genuine discovery in the whole story) that if the heating of the carbonate was done in a certain way, then the resulting oxide was not fluffy and hygroscopic, but heavy and granular, and would form a dispersion simply by stirring with water.This was Henry’s Magnesia, a product whose real and imaginary virtues were so loudly extolled by Thomas as to earn him the local nickname of ‘Magnesia Henry’. Thomas Henry, j r (left) and his brother Peter (above). Thomas Henry had three sons; the two eldest must have been a sad dis- appointment to him. Young Thomas made a promising start, but either he, or perhaps his father, could not decide what he was to do for a living, and he had a bewildering succession of jobs and courses of training. He was also friendly Farrar, Farrar and Scott 41 with Thomas Cooper and James Watt junior, young men of very radical politics; and Manchester, in the 1790s, with the French Revolution going sour after its early idealism, was an uncomfortable place for radicals.Cooper’s newspaper, the Manchester Herald, had its premises wrecked; Thomas Walker, a most respectable merchant and a member of the Lit and Phil, was tried for treason (a hanging matter) and only acquitted when the prosecution witnesses admitted perjury. Old Thomas kept his head well down, but young Thomas may not have been so prudent; in the end he sailed rather hurriedly for America, though his motives for doing so were not entirely political-he had been engaged in a chemical enterprise in Anglesey, on the edge of the great copper mines of Parys Mountain, and had contracted heavy debts which he had no prospect of paying. In America, he attached himself to the circle around Priestley, who went into exile about the same time, after the Birming- ham riots had wrecked his house and laboratory.Priestley seems not to have been able to do much for young Thomas, who eventually became a ship’s surgeon, and died of fever in the West Indies in 1798. Of the other son, Peter, we know almost nothing. The other Henrys are curiously silent about him in their letters, and we suspect that he may have been the black sheep of the family. He was trained as a chemist, but joined the army, and as Captain Peter Henry died of fever in India in 1808. WILLIAM HENRY This left only the youngest son, William, who turned out to be the most important, scientifically, of the family.A childhood accident, in which he was seriously injured by a falling beam, made him an ailing and bookish boy; for the rest of his life he was seldom free for long from pain and illness, which led eventually to his tragic death. He went to Edinburgh as a medical student in 1797, but after a year his father called him home (this must have been the time when he realized that young Thomas and Peter were not going to be of much use), took him into partnership, and put him in charge of the magnesia factory. In 1805, William Henry returned to Edinburgh to complete his studies, and took his MD. The years between these two periods at university were the busiest and most productive in his life.He diversified the magnesia business in two directions which are both interesting. About 1803 the Henrys started to make soda water (COz in water under pressure) for medicinal use. There is nothing startling about this; many others were doing the same. But it is interesting to remember that it was a manufacturer of soda water who dis- covered Henry’s Law, which is about the solubility of gases in liquids under pressure. Secondly, from 1799 to about 1802, William Henry was making alkali (soda) by a process which he was anxious not to disclose. We can, however, eliminate most of the likely possibilities for various reasons, and we think it probable that he was operating the first Leblanc process in Britain.Outside the factory, he played an active part in the early days of the gas industry, advising Boulton and Watt when they installed gas lighting into a cotton mill for the first time (Phillips and Lee, Salford, 1805). He published the first few editions of his successful textbook, The elements ofchemistry ; he ran a R. I. C. Reviews 42 William Henry, the youngest son. medical practice; he married and started a large family. Not least, he col- laborated with Dalton during the crucial years when Dalton was thinking out the atomic theory, and laying the foundations of all subsequent chemistry. Farrar, Farrar and Scott 43 When Dalton came to the Manchester Academy in 1793, he was not a chemist; he was a meteorologist. Up to 1800 and beyond, his reputation rested on his studies of weather.But it seems that, from his studies of the atmosphere, and the problem of how the different gases in the air stayed mixed, instead of separating out into layers, he had begun to entertain vivid and concrete speculations about the particles of these gases and the forces between them. He was not the first person to do so; like most English scientists, he was following reverently in the footsteps of Newton. But Dalton was not content merely to touch his hat to Newton. He had a great simplicity of mind which forced him to ask crude, naive questions about atoms. How big are they? How many of them are there? What different kinds exist, and how do they differ from one another? His attempts to answer these questions brought him to chemistry, especially the chemistry of gases; and it must have been from his friends Thomas and William Henry, pneumatic chemists both, that Dalton learnt his chemistry-though as a chemist he never became more than barely competent.In his early work on gases, Dalton discovered his law of partial pressures, working hand-in-glove with William Henry, who was doing his solubility work at the same time. The interdependence of their work at this period is shown by Henry’s Law, which is very simple (solubility varies as pressure) and was studied in a very simple apparatus; but the interpretation of the results was far from simple. This was because, in those days, pure gases were hardly to be had.All were mixed with more or less air, which greatly confuses the experimental results-but they can be brought into order by a knowledge of the law of partial pressures. About this time (1803) it seems to have dawned upon Dalton, perhaps through talking about chemistry to Henry, that the answer to one of his naive questions lay ready to hand in analytical chemistry. He had already grasped the idea that each different element (as recently listed by Lavoisier) consisted of one particular kind of atom, and that these kinds of atom differed in weight. Now he saw that he could determine the relative weights of atoms quite easily from the results of chemical analysis. Thus, if a compound AB contains 63 per cent by weight of element A, and 37 per cent of B, then ~~~ weight of atom A weight of atom B = 63/37 and by taking any atom (say hydrogen) as unity, one can construct a table of atomic weights.Dalton published the first such rudimentary table towards the end of 1803. Now to do this, and to press on with this major breakthrough, he wanted two things. First, he would want to know all that had been done in chemical analysis up to that time, and Henry could tell him. Secondly, published R. I . C. Reviews analyses would not be enough; Dalton would want to do his own, and he must have apprenticed himself to Henry to learn how to do it. We need not go on with the later development of the atomic theory, leading to the publication of Dalton’s New system in 1808. The point is made; at a vital stage in the evolu- tion of the atomic theory a chemist was needed, William Henry was at hand to help, and he helped generously.44 After William Henry finally came back, as Dr Henry, from Edinburgh in 1807, he took up research again; but it is clear from his private letters that his main preoccupations were the magnesia factory and his family-research had to take a back seat. He did a lot of work on the analysis of coal-gas, how its composition varied according to the variety of coal used, temperature of carbonization, and so on; tedious stuff, but essential for the industry, and it remained standard work for 40 years or more. His work on controversial matters, such as the nature of chlorine (some thought it an element, some an oxide) is marred by a sort of intellectual timidity, or perhaps excessive fair mindedness, which is also apparent in his textbook.Seeing both sides of a question may be a great virtue, but it seldom makes for productive science. Even on the question of the atomic theory, in whose birth he had played such a vital part, he did not fully commit himself until the last editions of his text- book, in the late 1820s. Perhaps William Henry’s best work, certainly the most interesting, was done towards the end of his life, during the great cholera epidemic of 1832. There is not space here to describe this work, even in summary fashion. It must suffice to say that in those days before bacteria had been discovered, Henry developed a chemical theory of contagion which, though wrong, is ingenious and plausible, and made sense of a great many confusing medical observations.On the basis of this theory he constructed a steam-heated apparatus for dis- infecting clothes and bedding. If this had been widely used during the epidemic it might have saved many lives. It is what is now called a ‘sterilizer’ but this word implies the killing of something living, and Henry did not think he was doing that; he thought he was isomerizing (by moderate heat) the complex molecules of the supposed chemical contagions into harmless isomerides. He was, in his way, groping towards the structural organic chemistry that came in the 1860s. At the time of this work on cholera, William Henry was already a very sick man. He spent the last years of his life in almost continual pain; partly due to his childhood accident, partly to painful tumours on his hands.From certain hints, it seems that he may have had periods of actual insanity. In August 1836, his family packed him off to the British Association meeting in Bristol, along with John Dalton, in the hope that’the change and the company might do him good. But when he came back he was quite distracted; in the early morning of September 2, 1836, he crept downstairs to the private chapel attached to his house and shot himself. LATER GENERATIONS Only one of William Henry’s sons lived to maturity. This was William Charles Henry, a young man of great scientific promise, but a rather baffling per- sonality. Unlike his father and grandfather, he was born into a wealthy house- hold with an assured social position, and with a scientific tradition going back two generations.He was a pupil of Dalton when at the height of his powers, then he studied medicine at Edinburgh. His earliest research work was on the physiology of the nervous system but, like Thomas and William before him, he seems to have turned away from medicine to chemistry. In 1835 he went off to Farrar, Farrar amd Scott 45 Germany for a year to turn himself into a proper chemist, thus pioneering a trail which was to become very well worn as the century went on. He went to Rose’s laboratory in Berlin and, more importantly, to Liebig in Giessen. German university life had the same effect on Charles Henry as it did on hundreds of other young Englishmen-for the rest of his life he looked back on those few months in Giessen as a sort of Arcadia, which could be remembered but never recaptured.He came back to Manchester in the summer of 1836, full of enthusiasm for chemical research; there were even plans for Liebig to come to Manchester and collaborate with him on a study of the effect of pressure on gas reactions. The importance of such a study, if it had ever been carried out, need hardly be emphasized. But he came back to find his father at the end of his tether, and the laboratory in a shambles; then a few weeks later came the tragic end described above. His father’s suicide shook Charles Henry to the core. In his letters to Liebig there is no more about plans for research, and he becomes sour about science in general; ‘the only science pursued in this town is that of making money, and I do not hear of much that is new in London’.Liebig did come to visit him the next year, and was mightily impressed by the opulence of the Henry household. He had seen nothing like it in Germany; washbasins in the bedrooms, well-trained servants all over the place, frequent large(but not very tasty) meals. But there was no talk of scientific collabora- tion, and Liebig was in fact witnessing the end of an era-the Henrys in Manchester. In September 1837, Charles Henry retired, from science and even from business, at the ripe age of 33. The family moved to the house and estate of Haffield in Herefordshire, and there for 55 years Henry lived the life of a Liebig’s laboratory about 1850.R.I.C. Reviews 46 wealthy country gentleman, with a dilettante interest in classical literature and a taste for foreign travel. The only noteworthy thing that he did, slowly and with obvious reluctance, was to write a life of Dalton. As Dalton’s pupil, friend, and medical adviser, he had the opportunity to write one of the greatest of scientific biographies. All that need be said is that he failed; the resultant book was a very disappointing one. The magnesia factory was left in the hands of a manager, and Henry seldom saw it again. The stuff evidently sold well, and we know that it brought in a considerable income to the family. It must have lived on its reputation (‘brand loyalty’ we call it nowadays) for it was hardly ever advertised. The process was never improved, cheapened, or altered in any way; it was carried on by skilled workmen who were familiar with every detail, but who had no knowledge of chemistry.When Charles Henry died, the factory passed to his son, Frank, a professional soldier (none of his 12 children showed the slightest trace of any interest in science), then to Frank‘s sons, Gilbert and Vivian. We have been fortunate enough to tjace one of the last employees of the factory, Mr David Dobson, who was able to describe in vivid detail how the place was run in the 1920s, a quaint and pleasing survival of an 18th century pharmaceutical firm. About once a year, Mr Dobson would go to the station to meet Gilbert Henry, an immensely tall and dignified man in a long astrakhan coat, and conduct him with due ceremony to the factory to inspect the books, and taste the magnesia for traces of lime, to ensure that the standards of 1772 were being kept up.Quaint and pleasing it may have been, but no longer profitable; the com- petition of firms like Boots hit hard. After a pathetic attempt to restore its fortunes by distributing fancy blotting-pads, T. & W. Henry was finally sold to BDH in 1933 for the derisory sum of E100. After a brief period as ‘Henry’s Garage’ the factory lay derelict for many years. Early last summer a bulldozer levelled the site; the very end of the story of the Henrys of Manchester. ACKNOWLEDGEMENT The authors are grateful to Mr Frederick Henry and Mr Gerard Henry for providing photographs of portraits in the possession of the family.The quotation from T. S. Eliot is reproduced by kind permission of Messrs Faber and Faber. 47 Farrar, Farrrir and Scott Sixth Grove LectureTHE HENRYS OF MANCHESTERW. V. Farrar, BSc, PhD, and Kathleen R. Farrar, BSc, PhDDept of History of Science and Technology, UMIST, Manchestei IE. L. Scott, MScStamford High School, Stamford, LincsThomas Henry’s early life . . .. .. . . . . . . 35Manchester life in the late 1700s . . .. . . . . . . 37Henry’s magnesia . . * . .. . . .. . . . . . . 40William Henry . . .. . . . . .. . . . . .. 42Later generations . . . . . . .. . . . . . . . . 45Most history is about great men, and the history of science is no exception.Lavoisier, Dalton, Berthollet, Berzelius, set the course of 19th centurychemistry; we know and we write a lot about such people, because they arevery important.But let us think of the other side of the coin-of the peoplewhose courses were set by the great men, the scientists of second rank, the‘common scientists’. It is these people, after all, who do 99 per cent of allscience, who carry on the daily business of science. They teach, they work inindustry, they write textbooks; they do their bits of research which once in alifetime may touch greatness-or may not. The Henry family of Manchesterwere such ‘common scientists’, and we have found them a very rewardingstudy. They did all the things just mentioned, and ran medical practices aswell; one of them, William Henry, just touched the edge of fame with ‘Henry’slaw’ about the solubility of gases.They were all in contact with a great man,John Dalton, who owed to them more than he ever admitted, or perhaps evenknew. They fit very well T. S . Eliot’s lines about J. Alfred Prufrock:No, I am not Prince Hamlet nor was meant to be.Am an attendant lord, one that will doTo swell a progress, start a scene or twoAdvise the prince. ..THOMAS HENRY’S EARLY LIFEThomas Henry was born in Wrexham, the son of a dancing-master. Now onewould not have thought that a dancing-master in 18th century Wrexham wouldmake a very fat living; but his father intended to send Thomas to Oxford, andthen into the Church.There is in fact a little mystery about Thomas’s father,and we have a suspicion (it is no more) that he may have been a natural son ofLord Bulkeley, who ruled Anglesey almost like an independent kingdom.Farrar, Farrar and Scott 3W i I liam (? I 700- I 774)IThomas I C (I 734- I8 16) Ellis (1743-1815)Thomas(I 767- 1798) Peter William (1774-1836)I ( 1769- I 808)William Charles (18044892)ISimplified family tree of the Henry family. Only male members who lived t o maturit)are shown.However this may be, there was enough money to think of sending Thomas tathe University, and it is said that a horse had even been hired to take himthere; but at the last minute the family got cold feet ‘with the uncertainty ofeventual success’.The horse was sent back to the stables and the disappointedboy apprenticed to a local apothecary. Halfway through his time, Thomas’smaster died, and he finished his apprenticeship over the border at Knutsford inCheshire. In either Wrexham or Knutsford his interest in chemistry wasaroused, improbable though it may seem, by reading the Latin text of Boer-haave’s Elementae chemiue, a book which, as his son said, ‘was not calculatedto present the science in its most fascinating aspect’. But it is difficult to thinkof a better education that he could have had in chemistry in those days;Boerhaave and the apothecary’s shop-no university could have taught himmore.36 R.I.C. ReviewWilliam Henry (left), father of ThomasHenry, shown above as a young man.When he was about 20, Thomas left Knutsford to become assistant to aleading apothecary of Oxford.Two important things happened to him there.His master’s practice lay among University men, and he met some of his oldschoolfellows from Wrexham Grammar School, who were friendly towardshim, and enabled him to continue his education in an informal fashion.Secondly, he became acquainted with another apothecary, Samuel Glass, whomade magnesium carbonate for medicinal purposes; we shall hear more ofhim later. After a few years at Oxford, Thomas declined an offer of a partner-ship, went back to Knutsford, started his own apothecary’s business andmarried a relative of his former master. He must have prospered, for in 1764he bought a practice in fashionable St Ann’s Square, Manchester-and this iswhere the story really begins.Manchester in 1764 was a mere country town (pop. 17000).Its almostexplosive growth had barely begun; but its growth and its wealth were suchthat an able (and personable) young apothecary could not fail to prosper, andThomas practised very profitably for nearly 50 years. Unlike most men in sucha position, however, he did not rest content with professional success and agrowing family; he soon began to extend his energies in other directions-intoindustrial ventures, original work in chemistry, and the educational andintellectual life of Manchester.MANCHESTER LIFE IN THE LATE 1700sTo deal with the last matter first, at some time in the 1770s Thomas Henry leftthe Established Church, and became a Unitarian.This was a large, influential,wealthy (but rather unpopular) sect ifi Manchester at that time, which wor-Farrar, Farrar and Scott 3shipped at Cross Street Chapel. This religious dissent, coupled with his interestin science, brought Thomas on to the fringe of the Lunar Society, aninformalgroup of experimenters and speculators centred in the Birmingham area, andon the personality of Matthew Boulton, Watt’s partner. He became friendlywith many of the ‘Lunaticks’ including Priestley (on whose recommendationhe became FRS in 1775), James Watt and his son (also called James), andJosiah Wedgwood the potter.Manchester at that time must have held as many men of real intellectualdistinction as London itself.There was Thomas Percival, Charles White, JohnFerriar, all with an honourable place in the history of medicine; the mathe-matician Henry Clarke, the Unitarian minister Thomas Barnes, wealthygentlemen of wide interests like T. B. Bayley; and also industrialists con-sciously seeking a scientific basis for their craft-Thomas Henry himself, JohnWilson the dyer, Thomas Cooper the bleacher, later James Watt junior (whocame to work in Manchester) and the Scottish engineer Peter Ewart. Many ofthese, but not all, were Unitarians; many, again not all, radical or evenrepublican in politics, with admiration for the recent American revolution.It seems that a number of these people, with the example of the LunarSociety in mind, began to meet in each other’s houses of an evening, to hear orread a paper on some scientific or philosophical topic.But unlike the LunarSociety, which did not outlive its founders, the Manchester group felt the needof some formal and permanent organization; this was formed in 1781 as theManchester Literary and Philosophical Society (the ‘Lit and Phil’), withregular meetings in a room at the back of Cross Street Chapel. Percival waspresident, and he, Barnes, and Thomas Henry were the real moving spirits. In38 R.I.C. ReviewAbove and left: Manchester in the late 1700s.spite of the heavy Unitarian and Radical bias among its members, the Societywas anxious not to be identified in the public mind with religious or politicalfaction; religion and politics were forbidden topics of discussion.It was ofcourse into this congenial gathering of dissenting scientists who left theirpolitical views at the door, that John Dalton was received when he came toManchester in 1793.Thomas Henry’s first paper read to the Lit and Phil was ‘An essay on theconsistency of literary and philosophical interests with commercial pursuits’-a plea for a ‘liberal’ education for the sons of a mercantile and manufacturingcommunity. Barnes also spoke to the same effect, and in 1783 the Lit and Philtried to put its ideals into practice by founding the Manchester College of Artsand Sciences, in which Thomas Henry lectured on chemistry, dyeing, andbleaching. This institution, with its evening lectures to young artisans, fore-shadowed in many respects the Mechanics’ Institutes of the 1820s.Perhaps itcame before its time, for its life was short; the last advertisements appeared inthe Manchester newspapers in the autumn of 1787. One account of its declinewas that it was due to ‘a superstitious dread of the tendency of science to unfityoung men for the ordinary details of business’ ; but Thomas Henry himself, ina letter written at the time, had no doubt that ‘bigotry and political rage’ wasthe cause. The College, in fact, split the Lit and Phil into two factions, and ledto wholesale resignations.The College should not be confused (though it often is) with the ManchesterAcademy, founded in 1786 by the same group of people, with Barnes asPrincipal. This was a Dissenting Academy of the ordinary kind, largelyresidential, a direct successor to Warrington Academy which had foundered aFarrar, Farrar arid Scott 3short time before.This was the Academy at which Dalton taught; ThomasHenry and his son, Thomas junior, continued their chemical lectures in it untilyoung Thomas went to America in 1794. This time the Lit and Phil were a tgreat pains to dissociate themselves from the Academy, by a public dis-claimer in the newspapers.About Thomas Henry’s research work I shall not say much, because it wasof no lasting importance. He, and indeed all the Henrys, were concerned withthe chemistry of gases-pneumatic chemistry. Thomas was maturing as achemist just at the time when there was a dawning realization that there weredifferent gases; different chemical individuals, not just bad air, and good air,and air with a smell; and he was interested in working out some of theimplications of this fascinating new idea. ‘Fixed air’ (COz) was the most avail-able of the gases, and he and Percival did some experiments on the effect ofCOZ on the growth of plants which might, in more expert hands, have ledthem to an understanding of photosynthesis; but they missed it, and thesuccess went to Priestley and Ingenhousz.There was also his enthusiasm forpneumatic medicine; these new gases would be a means of introducing chemi-cal substances into the body through the lungs, and this might have interestingmedical consequences. Indeed, in the (lucky) hands of Humphry Davy, it led alittle later to the discovery of the effects of nitrous oxide, though not, curiously,to the discovery of anaesthesia.But we suspect that Henry only made hisunfortunate patients cough and splutter.Thomas Henry was not a great scientist, nor even a good one. He was anenthusiastic amateur, with an incurable optimism about what science could do,and a burning ambition to spread a knowledge of science all through the com-munity, especially to people working in industry, from mill-owner to artisan.This he shared with his colleagues in the Lit and Phil (and with revolutionaryFrance); and he and his friends prepared the ground in Manchester for the nextgeneration, the real professionals-his son William, and John Dalton.HENRY’S MAGNESIAWe cannot leave Thomas Henry without saying a little about the source of thefamily’s wealth; the magnesia factory.The 18th century, whatever else it mayhave been, was the great century of overeating, and indigestion powders werethe best-selling lines in the apothecary’s shop. You can ease the pangs ofstomach acidity by taking chalk, but this causes constipation; soon after 1700 anew (at first secret) remedy was found in magnesium carbonate, which neutra-lizes acidity effectively and is also a mild laxative. Among the people who mademagnesium carbonate for sale was the apothecary Samuel Glass, who had alittle factory on Cowley Marsh, on the outskirts of Oxford, when ThomasHenry was there as a young man. Thomas later said himself, with devastatingcandour, how he had lived in the neighbourhood of ‘a gentleman .. . celebratedas the preparer of the most genuine magnesia. . . never having been ablemyself to make magnesia comparable to his. . . I was desirous of gainingsome intelligence as to his process; and was at last so fortunate as to obtainsome useful hints’.With the ‘hints’ obtained from Mr Glass, whether with that gentleman’s40 R. I. C. ReviewThomas Henry, j r (left) and his brotherPeter (above).knowledge or not, Henry began the production of magnesia in Manchester in1772. However, the next year, with typical 18th-century rancour, he put out apamphlet entitled Strictures on Glass’s magnesia, alleging that not only did the4 oz bottles contain a mere l i o z , but that the contents ‘so puffed in everynewspaper’ contained a great deal of chalk.This, as Henry no doubt intended,started a battle of pamphlets between himself and the successors to Glass(Glass probably being dead by this time). Much learned-sounding abuse wasflung by both sides; but the interesting thing is this-Henry knew instinctivelywhat he meant by a pure substance. His opponents, who were not chemists,did not. The concepts of ‘chemical purity’ and ‘chemical individuality’ areabsolutely basic to the development of chemistry, and it is fascinating to seethem being hammered out on the anvil of a minor commercial squabble.At first, Henry, like Glass, made magnesium carbonate. But soon he foundthat the oxide was an even more satisfactory product. It was more effective ona weight basis, and caused no distressing evolution of gas on contact withstomach acid.He also found (and this, kept a close secret, was the only genuinediscovery in the whole story) that if the heating of the carbonate was done in acertain way, then the resulting oxide was not fluffy and hygroscopic, but heavyand granular, and would form a dispersion simply by stirring with water. Thiswas Henry’s Magnesia, a product whose real and imaginary virtues were soloudly extolled by Thomas as to earn him the local nickname of ‘MagnesiaHenry’.Thomas Henry had three sons; the two eldest must have been a sad dis-appointment to him. Young Thomas made a promising start, but either he, orperhaps his father, could not decide what he was to do for a living, and he hada bewildering succession of jobs and courses of training.He was also friendlyFarrar, Farrar and Scott 4with Thomas Cooper and James Watt junior, young men of very radicalpolitics; and Manchester, in the 1790s, with the French Revolution going sourafter its early idealism, was an uncomfortable place for radicals. Cooper’snewspaper, the Manchester Herald, had its premises wrecked; Thomas Walker,a most respectable merchant and a member of the Lit and Phil, was tried fortreason (a hanging matter) and only acquitted when the prosecution witnessesadmitted perjury. Old Thomas kept his head well down, but young Thomasmay not have been so prudent; in the end he sailed rather hurriedly forAmerica, though his motives for doing so were not entirely political-he hadbeen engaged in a chemical enterprise in Anglesey, on the edge of the greatcopper mines of Parys Mountain, and had contracted heavy debts which hehad no prospect of paying.In America, he attached himself to the circlearound Priestley, who went into exile about the same time, after the Birming-ham riots had wrecked his house and laboratory. Priestley seems not to havebeen able to do much for young Thomas, who eventually became a ship’ssurgeon, and died of fever in the West Indies in 1798.Of the other son, Peter, we know almost nothing. The other Henrys arecuriously silent about him in their letters, and we suspect that he may havebeen the black sheep of the family. He was trained as a chemist, but joined thearmy, and as Captain Peter Henry died of fever in India in 1808.WILLIAM HENRYThis left only the youngest son, William, who turned out to be the mostimportant, scientifically, of the family.A childhood accident, in which he wasseriously injured by a falling beam, made him an ailing and bookish boy; forthe rest of his life he was seldom free for long from pain and illness, which ledeventually to his tragic death. He went to Edinburgh as a medical student in1797, but after a year his father called him home (this must have been the timewhen he realized that young Thomas and Peter were not going to be of muchuse), took him into partnership, and put him in charge of the magnesiafactory.In 1805, William Henry returned to Edinburgh to complete his studies, andtook his MD.The years between these two periods at university were thebusiest and most productive in his life. He diversified the magnesia business intwo directions which are both interesting. About 1803 the Henrys started tomake soda water (COz in water under pressure) for medicinal use. There isnothing startling about this; many others were doing the same. But it isinteresting to remember that it was a manufacturer of soda water who dis-covered Henry’s Law, which is about the solubility of gases in liquids underpressure. Secondly, from 1799 to about 1802, William Henry was makingalkali (soda) by a process which he was anxious not to disclose. We can,however, eliminate most of the likely possibilities for various reasons, and wethink it probable that he was operating the first Leblanc process in Britain.Outside the factory, he played an active part in the early days of the gasindustry, advising Boulton and Watt when they installed gas lighting into acotton mill for the first time (Phillips and Lee, Salford, 1805).He published thefirst few editions of his successful textbook, The elements ofchemistry ; he ran a42 R. I. C. ReviewWilliam Henry, the youngest son.medical practice; he married and started a large family. Not least, he col-laborated with Dalton during the crucial years when Dalton was thinking outthe atomic theory, and laying the foundations of all subsequent chemistry.Farrar, Farrar and Scott 4When Dalton came to the Manchester Academy in 1793, he was not achemist; he was a meteorologist.Up to 1800 and beyond, his reputation restedon his studies of weather. But it seems that, from his studies of the atmosphere,and the problem of how the different gases in the air stayed mixed, instead ofseparating out into layers, he had begun to entertain vivid and concretespeculations about the particles of these gases and the forces between them. Hewas not the first person to do so; like most English scientists, he was followingreverently in the footsteps of Newton. But Dalton was not content merely totouch his hat to Newton. He had a great simplicity of mind which forced himto ask crude, naive questions about atoms. How big are they? How many ofthem are there? What different kinds exist, and how do they differ from oneanother? His attempts to answer these questions brought him to chemistry,especially the chemistry of gases; and it must have been from his friendsThomas and William Henry, pneumatic chemists both, that Dalton learnt hischemistry-though as a chemist he never became more than barely competent.In his early work on gases, Dalton discovered his law of partial pressures,working hand-in-glove with William Henry, who was doing his solubilitywork at the same time.The interdependence of their work at this period isshown by Henry’s Law, which is very simple (solubility varies as pressure) andwas studied in a very simple apparatus; but the interpretation of the resultswas far from simple. This was because, in those days, pure gases were hardlyto be had. All were mixed with more or less air, which greatly confuses theexperimental results-but they can be brought into order by a knowledge ofthe law of partial pressures.About this time (1803) it seems to have dawned upon Dalton, perhapsthrough talking about chemistry to Henry, that the answer to one of his naivequestions lay ready to hand in analytical chemistry.He had already graspedthe idea that each different element (as recently listed by Lavoisier) consistedof one particular kind of atom, and that these kinds of atom differed inweight. Now he saw that he could determine the relative weights of atoms quiteeasily from the results of chemical analysis. Thus, if a compound AB contains63 per cent by weight of element A, and 37 per cent of B, thenweight of atom Aweight of atom B = 63/37 ~~~and by taking any atom (say hydrogen) as unity, one can construct a table ofatomic weights.Dalton published the first such rudimentary table towards theend of 1803.Now to do this, and to press on with this major breakthrough, he wanted twothings. First, he would want to know all that had been done in chemicalanalysis up to that time, and Henry could tell him. Secondly, publishedanalyses would not be enough; Dalton would want to do his own, and he musthave apprenticed himself to Henry to learn how to do it. We need not go onwith the later development of the atomic theory, leading to the publication ofDalton’s New system in 1808. The point is made; at a vital stage in the evolu-tion of the atomic theory a chemist was needed, William Henry was at hand tohelp, and he helped generously.44 R.I . C. ReviewAfter William Henry finally came back, as Dr Henry, from Edinburgh in1807, he took up research again; but it is clear from his private letters that hismain preoccupations were the magnesia factory and his family-research hadto take a back seat. He did a lot of work on the analysis of coal-gas, how itscomposition varied according to the variety of coal used, temperature ofcarbonization, and so on; tedious stuff, but essential for the industry, and itremained standard work for 40 years or more. His work on controversialmatters, such as the nature of chlorine (some thought it an element, some anoxide) is marred by a sort of intellectual timidity, or perhaps excessive fairmindedness, which is also apparent in his textbook.Seeing both sides of aquestion may be a great virtue, but it seldom makes for productive science.Even on the question of the atomic theory, in whose birth he had played such avital part, he did not fully commit himself until the last editions of his text-book, in the late 1820s.Perhaps William Henry’s best work, certainly the most interesting, wasdone towards the end of his life, during the great cholera epidemic of 1832.There is not space here to describe this work, even in summary fashion. It mustsuffice to say that in those days before bacteria had been discovered, Henrydeveloped a chemical theory of contagion which, though wrong, is ingeniousand plausible, and made sense of a great many confusing medical observations.On the basis of this theory he constructed a steam-heated apparatus for dis-infecting clothes and bedding.If this had been widely used during the epidemicit might have saved many lives. It is what is now called a ‘sterilizer’ but thisword implies the killing of something living, and Henry did not think he wasdoing that; he thought he was isomerizing (by moderate heat) the complexmolecules of the supposed chemical contagions into harmless isomerides. Hewas, in his way, groping towards the structural organic chemistry that came inthe 1860s.At the time of this work on cholera, William Henry was already a very sickman. He spent the last years of his life in almost continual pain; partly due tohis childhood accident, partly to painful tumours on his hands. From certainhints, it seems that he may have had periods of actual insanity. In August 1836,his family packed him off to the British Association meeting in Bristol, alongwith John Dalton, in the hope that’the change and the company might do himgood.But when he came back he was quite distracted; in the early morning ofSeptember 2, 1836, he crept downstairs to the private chapel attached to hishouse and shot himself.LATER GENERATIONSOnly one of William Henry’s sons lived to maturity. This was William CharlesHenry, a young man of great scientific promise, but a rather baffling per-sonality. Unlike his father and grandfather, he was born into a wealthy house-hold with an assured social position, and with a scientific tradition going backtwo generations. He was a pupil of Dalton when at the height of his powers,then he studied medicine at Edinburgh.His earliest research work was on thephysiology of the nervous system but, like Thomas and William before him, heseems to have turned away from medicine to chemistry. In 1835 he went off toFarrar, Farrar amd Scott 4Liebig’s laboratory about 1850.Germany for a year to turn himself into a proper chemist, thus pioneering a trailwhich was to become very well worn as the century went on. He went to Rose’slaboratory in Berlin and, more importantly, to Liebig in Giessen. Germanuniversity life had the same effect on Charles Henry as it did on hundreds ofother young Englishmen-for the rest of his life he looked back on those fewmonths in Giessen as a sort of Arcadia, which could be remembered but neverrecaptured.He came back to Manchester in the summer of 1836, full of enthusiasm forchemical research; there were even plans for Liebig to come to Manchesterand collaborate with him on a study of the effect of pressure on gas reactions.The importance of such a study, if it had ever been carried out, need hardly beemphasized.But he came back to find his father at the end of his tether, andthe laboratory in a shambles; then a few weeks later came the tragic enddescribed above. His father’s suicide shook Charles Henry to the core. In hisletters to Liebig there is no more about plans for research, and he becomessour about science in general; ‘the only science pursued in this town is that ofmaking money, and I do not hear of much that is new in London’.Liebig did come to visit him the next year, and was mightily impressed bythe opulence of the Henry household. He had seen nothing like it in Germany;washbasins in the bedrooms, well-trained servants all over the place, frequentlarge(but not very tasty) meals. But there was no talk of scientific collabora-tion, and Liebig was in fact witnessing the end of an era-the Henrys inManchester.In September 1837, Charles Henry retired, from science and evenfrom business, at the ripe age of 33. The family moved to the house and estateof Haffield in Herefordshire, and there for 55 years Henry lived the life of a46 R.I.C. Reviewwealthy country gentleman, with a dilettante interest in classical literature anda taste for foreign travel. The only noteworthy thing that he did, slowly andwith obvious reluctance, was to write a life of Dalton. As Dalton’s pupil,friend, and medical adviser, he had the opportunity to write one of thegreatest of scientific biographies. All that need be said is that he failed; theresultant book was a very disappointing one.The magnesia factory was left in the hands of a manager, and Henry seldomsaw it again. The stuff evidently sold well, and we know that it brought in aconsiderable income to the family. It must have lived on its reputation (‘brandloyalty’ we call it nowadays) for it was hardly ever advertised. The process wasnever improved, cheapened, or altered in any way; it was carried on by skilledworkmen who were familiar with every detail, but who had no knowledge ofchemistry. When Charles Henry died, the factory passed to his son, Frank, aprofessional soldier (none of his 12 children showed the slightest trace of anyinterest in science), then to Frank‘s sons, Gilbert and Vivian. We have beenfortunate enough to tjace one of the last employees of the factory, Mr DavidDobson, who was able to describe in vivid detail how the place was run in the1920s, a quaint and pleasing survival of an 18th century pharmaceutical firm.About once a year, Mr Dobson would go to the station to meet GilbertHenry, an immensely tall and dignified man in a long astrakhan coat, andconduct him with due ceremony to the factory to inspect the books, and tastethe magnesia for traces of lime, to ensure that the standards of 1772 werebeing kept up.Quaint and pleasing it may have been, but no longer profitable; the com-petition of firms like Boots hit hard. After a pathetic attempt to restore itsfortunes by distributing fancy blotting-pads, T. & W. Henry was finally soldto BDH in 1933 for the derisory sum of E100. After a brief period as ‘Henry’sGarage’ the factory lay derelict for many years. Early last summer a bulldozerlevelled the site; the very end of the story of the Henrys of Manchester.ACKNOWLEDGEMENTThe authors are grateful to Mr Frederick Henry and Mr Gerard Henry for providingphotographs of portraits in the possession of the family. The quotation fromT. S. Eliot is reproduced by kind permission of Messrs Faber and Faber.Farrar, Farrrir and Scott 4