155 XX.-On an Acid Feed-water from the Coal Field at Stellarton hTova Scotia and the Results of its Use. By Professor HOW,D.C.L. University of King's College Windsor Nova Scotia. INgiving an account of the mineral waters of this province I have mentioned* that a water with anacid reaction is reported to exist near Gair Loch in Picton county. The same county affords the strong brine originally described to the Chemical Society,t and also the subject of the present communication which is made by permission of Jesse Hoyt Esq. General Agent of' the Bcadia Coal Company at whose instance my examination was conducted. While from the nature of the circumstances under which the water is obtained to be detailed presently the results brought forward do not add to our scanty knowledge of the hypogene waters of the province except as indicating the probable origin of acid waters in coal strata they increase the number of facts recorded with regard to the chemistry of waters generally and they especially illustrate the action of impure feed-waters on boilers and the nature of the deposits and incrustations resulting from their use.For these reasons they ma,y not be unacceptable to the members of this Society as furnishing a subject for discussion. Mr. Hoyt sent me the water for analysis because he found it was having a very injurious effect upon his boilers ; he also furnished for examination the deposit and incrustation formed his object being to find a remedy for the evils observed. I speak of a water because although two waters were sent they proved to be so far of common origin that they intercommunicated and the considerable difference in their composition being rather in the quantity than the nature of their constituents probably arose chiefly from dilution by surface-water or from some other temporary cause connected with the weather.The waters were taken in December 1869 from an artificial pond and well respectively at the Acadia coal mines situated at Stellarton a name chosen recently February 1870 by the residents as distinctive for the locality from its furnishing the remarkable stellar-oil coal or stellarite a mineral substance first * Mineralogy of Nova Scotia p. 199. t At the Meeting held Peh. 16 1865. HOW ON AN ACID-FEED WATER described by myself," and at the same time compared with albertite and torbanite as distinct from coals.The pond was made to communicate with the well because the latter did not furnish enough water for the boilers. The pond rests upon the measures immediately underlying the Acadia seam of coal which is 20 feet thick and has the reputation of being remark- ably free from sulphur as are many of the coals of this field. Communication is made with the well which is sunk in the underlying sandstone by means of a tunnel driven through the same rock. With this exception there is no other member of the measures in actual contact with any of the water as the whole surface is covered with a tough red clay-drift of from five to twenty feet in thickness.The character of the water may to some extent be influenced by washings from dirt which is screened from the slack coal and piled in considerable quail- tities in the immediatevicinity of the pond and well. Hence it appears that the water is partly of surface origin. The water from the mine as pumped up is remarkably clear and is used in the neighbourhood for drinking purposes ; it does not mingle with that of the pond or well but is discharged at another point. The water from the pond was colourless and held a little yellow flocculent matter in suspension which was proved to contain hydrated peroxide of iron with a little organic matter and magnesia but no carbonates. It had no odour and no colour was given to lead paper placed in the air above the water aft8er shaking up ; its taste was chalybeate; it gave a black precipitate with sulphide of ammonium ; its reaction was decidedly acid; the gas evolved on boiling did not affect baryta-water.The following were the results of quantitative analysis of the filtered water made soon after collection. The nomenclature used in my report as more generally intelligible to practical men than any of the latest proposed is retained :-* Edin. N. P. Journal and Silliman's Journal 1860. FROM THE COAL FIELD AT STELLARTON ETC. 157 Contents of Pond Water in the Imperiul Gallon. Grains in 70,000. Sulphate of lime ................... 8-81 Sulphate of magnesia ................ 5.91 Sulphate of protoxide of iron.. ........4-96 Sulphate of potash .................. 1-53 Chloride of sodium .................. 0.28 Chloride of potassium ................ 0.67 Silica .............................. 0.25 Ammonia ......................... traces Organic matter ...................... small Free sulpliuric acid (oil of vitriol) ...... 1-92 24.33 Specific gravity at 57" Fahr. ...... 1000*299 The water increased mnch in acidity when boiled down; after about four-fifths had boiled away the amount of deposit was equal to about half a grain to the gallon; the residue on evaporation heated in a porcelain dish became black. The sul-phuric acid of the sulphates and the comparatively large imount of iron may have come chiefly from pyrites in the "djacent coal-dirt and the fi*ee sulphuric acid from the subse-pent alteration of protosulphate of iron.The well-water the actual feed-water of the boilers was very turbid and was constantly depositing a yellow substance mnsisting of hydrated peroxide of iron organic matter and ,uagnesia. Its reaction was distinctly but not strongly acid ; it had a strong chalybeate taste and gave a black precipitate with sulphide of ammonium; it had no odour gave more gas than that from the pond on boiling and the gas in this case also was not carbonic acid. The results of the analyses of the filtered water soon after its collectiou were the following :- 158 HOW ON AN ACID FEED-WATE‘k Contents of Well WLter in the Iinperial Gallon. Grains in 70,000. Sulphate of lime ....................25-69 Sulphate of magnesia. ............... 9.45 Sulphate of protoxide of iron ........ 4-58 Sulphate of potash.. ................ 6-44 Chloride of sodium.. ................ 0.40 Chloride of potassium.. .............. 0.88 Silica.. ............................ 0.52 Organic matter .................... very small Free sulphuric acid (oil of vitriol) ..,. 0.43 48.39 Specific gravity at 57” Fahr. ...... 1000*891 This water deposited the whole of its iron along with some magnesia and no doubt organic matter on boiling down ; when at about one-fifth of the original bulk its total deposit amounted to four grains for the gallon; this deposit contained 120 carbonates. The difference in composition between this water and the preceding may have arisen from their inter- communication being temporarily broken by a hard frost which occurred early in December and the dilution of the pond water during the subsequent “soft spell” in which the waters were collected.The sandstone of the tunnel and well would produce little change. It is evident that a good deal of iron has been removed doubtless by organic matter. The fiee sulphuric acid has probably been partly neutralized by carbonate of lime existing in the well water itself. At my request Mr. Hoyt tested the waters in the pond the well and the boilers with litmus paper and in each case found an acid reaction which I considered on observing the resulting tints of the papers returned to me to be about equal to that I had obtained in the bottled waters as received and as evaporated.The deposit or sediment formed in the boilers was of a bright red colour in dry and soft cakes up to an inch or so in thick- ness apparently uniform in quality. Heated in a tube it gave water with vapours smelling strongly of acrolein arising from the presence of grease introduced of course from the FROM THE COAL FIELD AT STELLARTON ETC. 159 machinery. It contained 110 carbonates and only the merest trace of magnesia; a few minute black specks were observed on solution in acid Analysis gave :- Water and greasy organic matter . . . . . . 9-11 Peroxide of iron and a little alumina . . . 54.34 Anhydrous sulphate of lime . . . . . . . . . . . . 36-55 The incrustation formed on the boilers was described as so compact as to be removed ~vitli much difficulty.As I received it the most solid portions were in cakes nearly a quarter of an inch thick in parts white and red inside as from a mixture of peroxide of iron and sulphate of lime ; some organic matter was also present. As a whole the incrustation was a dry mass of the colour of Turkey umber ; it contained twigs and fibres of roots. Heated in a tube it gave a good deal of water and oily white fumes containing acrolein ; carbonates were absent and a mere trace of magnesia was found with also a few minute black specks remaining as above on solution. The analytical results on selected hard portions were :-Water and greasy organic matter . . . . . 14-43 Peroxide ofiron and a little alumina .. . . 13.30 Sulphate of lime (anliydroiis) . . . . . . . . 72-27 It is not surprising that with such water as has been de- wribed the boilers should be much injured and that so large a quantity of iron should be found in the deposit a quantity which indeed may be called enormous when we find Dr. Phipson quoted as instancing a red deposit containing more than 9 per cent. of peroxide of iron as the result of the action of an impure water such as those contaminated with metallic salts and other kinds of refuse from chemical works and especially liable to induce corrosion." In addition to the simply chemical action of the sulphuric acid originally free and that liberated by the concentration of the Stellarton water which would of course attack even homo- geneous iron and whose influence would be largely increased * Phi pson on Boiler Dposits reviPwPd in Chemical Newa xvi 131.HOW ON AN ACID FEED-WATER ETC. by the electrical relations of the different portions of the boiler plates consisting no doubt of the electrically non-homoge- neous portions found as pointed out by Mr. Mallet in mought-iron and blister steel there would be similar if less injurious results from the action of the alkaline salts classed by Professor Chandler" as electrically corroding agents. If ang brass or copper should be in contact with the metal the electrical action on the iron would of course be intensified. The oxide of iron is derived partly from the water itself; but principally no doubt as a good deal must be deposited in the well from the decouiposition of the iron salts resulting from the action OP the boiler plates.Both in the deposit and incrustation minutc black specks were said to be present ; these were not given in the quantitative results as being too small in amount. They effervesced with nitric and with hydrochloric acid but remained black 60 that they no doubt contained iron a.nd graphitic carbon; and they may have been mechanically detached froni the boiler with the incrustation or have resulted from its occa- sional local burning into seales or from the local corrosion detailed by Mr. Paget in his interesting paper read before the Society of Arts and given in abstract in ths '' Chemical News," xi 219 230 in which he dwells at some length on the electrical relations to which I have only alluded. it Report on Water for Locomotives and Boiler Incrustations New York 1865.