J O U R X A L OF THE CHEMICAL SOCIETY. ABSTRACTS OF CHEMICAL PAPERS PUBLISHED IN BRITISH AND FOREIGN JOURNALS. General and Physical Chemistry. Refraction and Dispersion of Sodium Chlorate. By F; D WSAUD (C'ompt. rend., 113, 291-292).-The measurements were made with several different forms of refractometer, but the diverg- ences between the results obtained with different instruments did not seem to follow any definite law. The following are the indices of refraction at 2 Y :- a. B. C. n. b. F. 1.51097 1.51163 1.51267 1.51510 1.51933 1.52161 Cdg. Cd,@ Cd,,. Cd12. Cd,,. Cd 1s. 1.53883 1.54242 1.54421 1.54700 1.57203 1.58500 The mean variation of the index of refraction is -0*000057 per dtgree, and seems to be practically the same for all the visible rays. C. H. B. Re1 ation between the Index of Refraction, Density, Molecu- lar Weight, and Diathermanous Power of a Substance.By AYsfoPr'KE'r (Compf. Tend., 113, 418--421).-1f A is tho diathermanous conductivity of a certain substance, A = QMV, where M is the mass contained in unit area of substance of thickness kh, and V is the mean relocity. If k is proportional to the thickness a of a molecule, k = CF, where C is a constant. If the molecule is spherical, E = ( e / d j J , e being themolecu- lar weight. Suppose V = n - I , where n is the index of refraction, then where P is a correction applied on account of reflection. M = kXd, d being the densit'y of the liquid. AY = +Ce4 ds (?a - l)", VOL. LXII. b2 ABSTRACTS OF CHEMICAL PAPERS. The author verifies the above formula by observations with water, alcohol, benzene, chloroform, and carbon bisulphide.H. C. Emission Spectra of Neodymium and Praeseodymium Oxides and of Luminous Solids containing Neodymium. By L. HAITINGER (MonLitslL., 12, 362-367) -Welsbach found that prseseo- dymium oxide gives a continuous emission spectrum, and neo- dymium oxide a discont'inuous spectruin similar to that noticed by Bunsen in the case of didymium oxide. The author confirms Wels- hach's obserrntions with neodymium oxide, iising this oxide mixed with aluiniiiium oxide for the production of the spectrum. The liues are found to vary somewhat, both i n intensity and position, oil long-continued heat,ing of the mixed oxides, and also if magnesium is substituted for aluminium oxide. Prsseodymiuni oxide, which alone l i ~ s no emission spectrum, shows one when mixed with alumicium oxide.This behaviour mav, perhaps, be explnined by assuming that a higher oxide is fornied when the salt is heated alone, but not when mixed with other oxides. No emission spectrum was, however, obtained on heating prxwodymium oxide in a reducing atmosphere. The praence of a trace of neodymium i n calcium sulphide causes a phosphorescence, the spectruni of which is similar to the absorption spectrum of concentrated solutions of neodymium salts. Study of the Chemical Neutralisation of Acids and Bases, by means of their Electrical Conductivities. By D. BERTHELOT (Compt. rend., 113, 261-263).-A summary of the results of the researches previously published. Potassium hydn)xide, a strong base, with hydrochloric acid, acetic acid, or phenol gives compounds which have almost identical conductivities, behave as true salts, are stable in solution, and are not decomposed by water.Ammonia. a feebler base, with hydrochloric acid and acetic acid gives stable compounds, b u t with phenol only an unstable compound with a higher resistance than the normal salts, and, to a large extent, dissociated by water. Aniline, a still feebler base, gives with hydrocliloric acid a stable compound that is a goad conductor; with acetic acid an unfitable compound with a considerablj- higher resistaiice ; and u ith phenol only a lion-conducting mixture without any trace of combination. Experiments with the hydroxybenzoic acids. which unite the functions of an acid and A phenol, sliow that, whilst the presence of the two functions call be readily recognised, they affect, one anotheia in a manner more or less marked according to their relative positions; in the molecule.C. H. B. H. C. Calculation of the Specific Heat of Liquids. By G. HIXRICHS (Conzpt. rend., 113, 46x3471) .-In the liquid state, molecules rotate ~ o u n d the natural axis, for which the moment of inertia is a, minimum. Tf .i is the moment of inertia, M the mass of the molecule, and p the indius of gyration, i = Mpz* The total energs, c, of the molecule of a liyiiid is the snm of tlie energy of rotntioii and of the potential energy, which is a function @ of the absolute temperature T, c = liiT + M@(T) = Me,GENERAL AND PHYSICAL CHEMISTRY. 3 wherz c = 7;p?l' + @(T), the tot'al energy of unit mass.The specific heat, c, of unit mass will be obtained by differentiation of e with regard to T, c = K(rZ + @'(T). The author sbows that a formula of this kind holds i n the case of the ethereal salts of the fatty acids, taking Schiff's observations of the specific heats of salts of this series. H. C. Second Law of Thermodynamics and its Application to Chemical Phenomena. By H. LE CHATELIEE (Bull. SOC. Chilit. [3], 5, 837--840).-Carnot's principle is directly applicable to chemical changes, if all restriction as to the natnre of the equilibihm cstablished by the change is removed. Tlie same reasoning which is applied to the eshblishment of heat equilibrium may then be applied TO chemical eqnilibrium. The available energy obtainable from two different states of the sajme system will be the same for all reversible trausformations of the one state into the other, arid independent of the means emploped f o r rendering this energy available, and will be greater for reversible t h a n for non-reversible transformations. The author shows how from this principle mty b e deduced, in a verg sirriple manney, the iaws of isodissociation which he formerly ob- tained by a far more complicated process-starting from the t w o H.c. New Isot3errhal Curves for Carbonic Anhydride. By E. H. AblAGaT (Conyx!. rend., 113, 446--451).-The author has determined the isotliermals f o r carbonic anhydride for every 10" from 0" t o loo", and also for the temperatures 32", 35", 137", 198", and 258'. The pressures were taken up to 1000 atmospheres, and the method em- ployed was that described in former communications.The results are given in t;lbuli\r form, and the isothermal curves for each of the temperatures taken. The following table is given f w the pressures of liquefaction of carbonic anhydride a t the temperatnres under ex- amiriatioii :- cquivalent principles of Clausius. Temperature.. .. .. . . . . .. . . .. 0" 10" 20' 30" Pressure in atmospheres ,. . . . 35.4 44.4 56.4 70.7 The full discussion of the results is reserved for a future paper. Heat of Formation of Platinic Bromide and its principal Compounds. By L. PIGEON (Cornpi. rend., 113, 476--479).-Pla- tinic bromide, prepared hy carefully heating hydrogen platinic brorn- ide, was dissolved in water, 9.86 Cal. being developed.The solution was then reduced by metallic cobalt, the heat developed being i13.59 Cal. By subtracting tlie heat of formation of the cobalt bromide, 145.88 Cal., we get for the heat of formation of dissolved platinic bromide 32.29 Cal., and from this the heat of formation of the solid salt, 42.43 C d . Solid plaqinic bromide dissolved in hydro- biwrnic acid solution (1 mol. in 4 litres; gives rise to a development of 19.27 Cal., from which the heat of formation of a solution r,f H. c. b 24 ABSTRACTS OF CtEEMMICAL PAPERS. hydrogen platsink bromide from platinum, bromine, and hgdro- bromic acid is 60 7 0 Cal. The formation of the crystalline salt H,PtBr, + 9H,O is attended by the development of an additional 2.86 Cal. The author draws attention to the fact that the heats of fornia- tion of the compounds of p7atislnm nzld bromine are, when gaseous hromine is taken, very nearly-equal to the heats of formation of the similar compounds of platinum and chlorine.€3. c. Heats of Combustion and Formation of Nitrobenzenes. By BERTHELOT and MATIGXOX (Compt. ~ e ~ z d . , 113, 246-249) :- ----- Ortbodinit rohenzene. ........... Met,adinitrobenzeiie ............ Paradinitrobenzene ............ Tiinitrobenzene (1 : 3 : 5 ) . ...... Trinitrobenzene (1 : 2 : 4). ...... Heat of combus- tion, conutiint vol urn e . Cnl. + 704 -6 + 698.1 + 696 -5 + 665.9 + 680 -6 -- Heat of combus- tior., constant pressure. Cal. +703 5 + 697 ‘0 + 696.4 + 663 ’8 + 678 ‘5 -- Forma- tion from elements. -- Cal . + 0 . 5 +6.8 +8*4 + 5 . 5 - 9 . 2 Forrna- tion from nitric acid, --- Cal.+ 58 -3 + 64 ’8 + 66 4 + 90.9 t- 76 ‘ 2 It is clear that although the ralucs for t,he various isomerides are very similar, as i s usually the case, there are distinct diflerences, amounting to 1 per cent. in the case of the dinitro-derivatives, and to 2 per cent. in the case of trinityo-derivatives. The differences are also distinct in the case of the formation from nitric acid, and the heat deyeloped becomes less the niore advanced the substitution. The heat of formation of a nitro-derivative is always but slightly dif-ferent from that of the generating hydrocarbon ; and i t follows that the oxygen of the iiitroxyl group has nearly the same combustible power as if it were in the free state. Since the heah of formation becomes less as nitrakiorn advances, it follows that the combustible energy of the ox-j-gen gradually increases.The hearing of this result on the explosibility of nitro-derivatives is obvious. Calorific Value of Food Constituents and their Derivatives. By I!. STOHMAKX’ aiid H. LANGBEIX (J. pr. Chern. [2], 44, 336-399). --Stohmatin is surprised that Berthelot (Ann. Chiin. Phys. [GI, 22, 5) has not, quoted him as an authority on the thermochemistry of protei’ds and made use of his work on the subject (compare Abstr., 1885, 85’7). The authors have already dealt with the calorific values of animal fats (Abstr., 1831, 11) ; in this paper they summarise the calorific values which they obtain for various prote‘ids and the products of their change. Full data for the results, and details as to source of the compounds, are given.The following tables summarise the valiies, C. H. R.*pc---- N l a h i i ................. Vegetable iibi*iii.. ........ Serum albumin .......... Yynlonin.. .............. H ze inoglo hin ............ %[ilk w ~ e ' h , No. 1 . . ...... .. No. 2 . . ...... yolk of egg.. ............ Leguinin ................ Vitellin ................. u albu1nit~ ............ %& Elesh fibre, No. 5 ........ Crystallised dbun\iii.. .... Flesh, No. 3 ............ .. 3 0 . 1 ............ Blood fibrin ............. hwiiack's albumin ....... Wool fibre .............. Conglutin. .............. Skin fibroh.. ............ Yelit one ............... > Cliotidrin ............... Oaaein .................. Fibt.o.:n. ................Chitin.. ................ Calorific value per grain, cal. -- 5961 '3 5941 *6 5917 -8 5907.8 5885 -1 5867 -0 584!) '6 5840.9 5793 *1 5745 '1 5735 '2 5720 -5 5672 0 5662 -6 5640 '9 5637 * 1 5553 *o 5510.2 5479 -0 5355 -1 5298 8 51 30 *6 5039 *!I 4979.6 4 650 '3 Carbon. 55 '03 54 '39 53 *93 53 *64 54 -73 54 *02 5 4 *14 53 -50 53 -32 50 *27 5'5 -95 52.11 51 -48 52.02 58.93 50 -69 50 -20 50.18 49 -92 50.10 49 *14 48 '63 48-63 45 '15 - Hydrogen. 7 '20 6 '98 7-65 7 -4.4. 6.06 7 *33 6 -85 7.31 7 -17 7 .go 7 '50 7 *lo 6-76 7.30 7 '16 6 *68 6 -72 6 *74 5 '76 6 -45 6 -67 6.64 6.08 6 -4 -- - U1 t iinat,e coin posit ion. Nitrogen. 16 -91 15 -39 15 '15 15.76 16 -50 15 *52 15 '61 15 '26 15 '1.8 16'04 15 -19 16 '44 18' 14 16 '38 16 '36 16'72 14.5 1 16 '54 17 '51 18 -01 16'42 15 '37 46.34 18 *97 --- 6 -86(?) Sulpli iir.--- 0.18 1 '02 1 '18 1 -09 0 '46 0.75 0.78 1'11 0 '46 3'09 1'52 1 '03 0.96 1 '09 1'01 1-13 1 '89 3 *70 0 *79 0'30 1-24 1 *26 0 *95 - - Oxjgen. -- 20 -68 22 -28 22 09 22.07 22 -25 23 *38 22 *62 22 -82 23.97 24 *70 28 '85 23 *32 22 -66 23 -31 %2 *06 23 '67 22-84 24 -18 26 '02 25.79 27 -56 2? '44 26 *32 41.59 - Atomic proportiuns.6 LBSTRACTS OF OHlEMICAL PAPEHS. the atomic proport,ions in Table I being calculated to 720 carbon atoms to avoid decimals ; 72 is the proportion of carbon atoms found i n white of egg by Liebci-kuhn. Glycocine . . . . . . Alanine . . . . . . . . Leucine.. . . . . . . Barcosine . . . . . . Hippuric acid.. . Aspartic acid, . . Urea . . . . . . . . . . Asparagine. . . . . Xreatine (cryst.) Kreatine (an- hydrous).. . . . Uric acid . . . . . . Guanine . . . . . . . Caffe’ine . . . . . . . - Mol. weight . 75 89 131 89 1’19 133 60 132 1 49 131 168 151 194 Calorific value. .--- Cul. 234.6 387 ‘7 855 -8 401 -2 1014 ‘5 385 -2 152 -2 463 *5 553 -3 560 -0 460’5 586 *6 1014.9 - Heat of forma- tion. -- Cal. 125 -9 135 8 156.7 122.3 142 -0 232 a 3 79 -8 188 -5 202 -2 126 5 198 -5 55 *9 82.1 Calorific value tic- :ording t o Berthelot Gal. 234.9 389 ‘0 857.1 1012 ‘9 386 .8 151 -5 448.1 --- - - - 461 *4 - - -- B and A. Band A. B and A. B and A. Band A . Band P. B and A. M. B and A = Berthelot and Andr6, B and P = Bertlielot and Petit, M = Matipon. In connection with the first of these tables, the authors give another table showing the results which were obtained by Berthelot and Andre for some of the prote‘ids in the authors’ table; this table appears to be quoted from Ann. Chim.Phys. [S], 22, 25, which con- tains the same table as appears in Abstr., 1890, 937, but the numbers given here do not quite agree with those in the table referred to. If the valnes for elastin, wool-fibre, skin-fibroyn, chondrin, ossein, fibro’in, and chitin be excepted, the mean calorific value for tt e prote‘ids given in the first table is 5730.8 cal. Berthelot (Abstr., 1E90, 938) found 5691 cal. for this number ; the authors regard the mean, 5i11 cal., as representing the real value. This value would be given by the formula C720H11G1NlbiS502L38 ; Lieberkiihn’s formula is From the values given in the second table, the authors deduce the fol- lowiug generslisations :-(1) The substitution of CH, for a hydrogen atom in homologous series increases the calorific value by 156-157 Cal.(2) The calorific r a l ~ i e of a methyl group ahtached to a nitrogen atom is higher than that of one attached to a carbon atom. (3) The displacement of a hydrogen atom in A CH, group hy NH, raises the cnlorific value by 26.9 Crtl. (4) The displacenient of tbe hgdroxyl in a carboxyl group by NH, raises the calorific value by 78.6 Cal. The heat of combustion of carbnnic acid deduced from that of urea by means of this peneralisation is -5.0 Cal. Lnnguinine (Ann. Chia?. Il’hys. [S], 8, 133) found -4.3 Cal. and -10.75 Gal. for this number. GH,iaN,tSOm A. G. B.GENERAL AND PHYSICAL CHEMISTRY. 7 Maximum Density of Water. By H. N.VERSON (PhiZ. MU,^. [ S ] , 31, 337--392).-The author investigated the rate of cooliiig of quantities of water from 30" down to 0". His thermometer was read to 0.01" by means of a cathetometer. When the water waq not Ptirred, there was a sudden break in the cooliiig curve about 4*7", which is therefore to be considerecl tlie point of maximiim density. No bre*ak appeared when the water was stirred, the natural convec- tion currents not then having free play; but from the form of the curve it would seem that the specific heat of water between 0" find 12' is about 3 per cent. greater than between 16" and 30". Both the increased specitic heat and the maximum density are considered by the author to have their cause in an aggregation of (H,O)? molecules to (H20), molectiles about 4" as the water cools.J. W. Expansion of Water. By C. SCHEEL ( C h m . Centr., 1891, ii, 409-410 ; Inaug. Diss., Bedin).-The author has determined the expansion of water between 0" and 33" by means of a glass apparatuu, the volume being read off on a capillary tuhe. (For a complete description of it, see the original paper.) The absolute expansion of water was found to be 0.0408059, tlie minimuni being a t 4~0.38". Dilatation of Phosphorus and its Change of Volume at the Melting Point. By A. LKDUC (Cornpt. rend., 113, 259--%1).- Phosphorus expands almost regularly up to its melting point, which is M.2" on the mercurial theimometer, aiid 44.1" on the normal ther- mometer. A t this point, without any appreciable change OF tempera- ture, there is a considerable expansion, tlie ratio of the volunie of the solid phosphorus to that of.the liquid phosphorus bein:,. 1 : 1.0345. Kopp's number was 1.0:343. The expansion of either solid or liquid phosphorus can only be represented by a formula with three terms, but the abthor is not able to state the coefficients precisely. The value of the mean coefficients on the normal thermometer between 0" and 44.1" is 0*00037:', acll betwoen 26' and 50°, 0.000560, the latter being calculated on ttie volume a t 0". These values differ considerably from those given by KUPP. C. H. B. Capillary Constants of Salts at their Melting Points. By J. '~'RAURE (Ber., 24, 3U74-:3080).-l'he author has determined the capillary constants of a large number of salts at temperat,ures just above their melting points.The method adopted was that of weigh- ing the drops which fell from a single perforation in ft emnll disc that formed the end surface of a short cvliiider let in to the bottom of i L platinum or porcelain crucible. This crucible was so heated, by means of an ordinary gas flame or by the blowpipe, that the flame did not come in contact with the hanging drop. The salts investigated were potassium and sodium salts, and the ratios (T) of the weight of the drops to the weight of the water-drop at 0" from the same vessel are tabulated. From his results, the author deduces the following conclusions :-- Capillarity may be considered a '' colligntive " property. The con- J. W. L.B ABSTRACTS OF CHEMICAL PAPERS. stants for the salts of the fatty acids are unusually small, diminishing rapidly as the series is ascended. For the otheio salts the constants (T) of the potassium salts of monobasic acids lie between 112 and 157; of bibasic and multibasic acids, between 168 and 231.The limits for the constants of the corresponding sodium salts are 123-16!, and 189-325. The difference T,, - T, incveases with the number of cquivalents of the metal in the salts. It is doubtful if tri- and quadri-basic acids can, in this way, be distinguished from bibasic acids, but the author considers it always possible to distinguish between the latter and monobasic acids. The method points to the following formuh as being correct :-K2FZ, KZPZO,, Na3P206, K2 As~O,~. J. W. Mutual Solubility of Salts in Water. By W. W. J. N~cor, (Phil. Mag.[ 5 ] , 31, 369--387).-Uiider the heading '' The Mutual Solubility of Salts," the author groups the phenomena due to tJhe mutual influence of two salts on each other's solubility in water. IIe gives an historical survey of t h e work done on the subject, and pro- ceeds to communicate his own experiments on the chlorides and n ttrates of sodium and potassium taken in all possible combinations of pairs with a common constituent. The method of experiment adopted was as follows :-A salt was taken, ant1 solutions containing 1, 2, &c., gram-mols. of this salt in 100 gram-mols. of water were prepared. These solutions w e i ~ then satuixted ilf a detinite tempera- ture with the other salt added in excess, and the total salt in solution determined. Precisely similar determinations were made with definite niolecular solutions of the other salt. The solnbility of each salt separately i i i water was then determitied, and finally, the solubility of both salts when simultaneously added in excess to water was alao ascertained.'l'he results are presented in the form of tables, formulae, and curves, In general, the presence of one salt diminishes the solubility of the other, but i n the case of the nitrates of potassinm and sodium, t h e presence of the one in solution increases the solubility of the other.. (Compare Nernst, Abstr., 1890, 3 ; Le Blaric and Noyes, Abstr., 18131, 388.) J. W. Cryoscopic Behaviour of Dilute Solutions. By J. TRAURE (Ber., 24, 3071-3074).-Eykrn:tii1i and Arrheriius have pointed out, (Abstx., 1891, 972 and 1148) that the observations of the auihor on the freezing point of dilute.solutions, in particular of those of cane sugar, are not i n accordance with their own experiments, o r w i t h those of Tanimann end Pickering. The author upholds his numbers, and attributes the discrepancy to the other observers having cooled their solutions too far below tne freezing point before making ohser- vations. J. W. Automatic Replacement of Mercury in Sprengel Pumps. By A. VEIINEUIL (ULIIZ. Soc. Chim. [ ; 3 ] , 5, 748---750).-'l'lie mercury is cmntiiiuously and automatically transferred from the lower to the upper reservoir by t h e action of n water-pressure or similar piirnp,GENER1.L AND PHYSICAL CHEMISTRY. 9 tlie suction.tube of which is attached to the upper end t of a small bulb, connected by tubes a, b to both reservoirs, and placed about 40 cm.above the upper one. The contents of the lower reservoir are thus forced into the bulb by atmospheric pressure, and allow-ccl to fnil into the upper reservoir by their own weight. The tube a is 3 mm. in internal diameter, and is recurred at the lower end, the level of the mercury at that poiIit being so adjusted that much air and little mefcury passes up the tube; the tube b is 6 mm. ininternal diameter. It. is not intended to be used at starting, as it is found niorc convenient to transfer any considerable quantity of mercury by hand than to make the apparatus of unnecessarily large dimensions. An incidental advant,age is t h a t the mercury is bronglit into contact with air under conditions favourable to the oxidation of impurities.The a.pparatus is applicable to most existing mercury pumps. JN. W. Block Support for Tubes. By A. GAWALOVSKI (Zeit. anal. CItern., 30, 581-583).-Two elongated blocks of hard wood, laid side10 ABSTRACTS OF CHEMICAL PAPERS. by side, have rectangular grooves ploughed in their contiguous faces, so as to form a channel, the cross section of which corresponds, approximately, with the shape of the bulbs of R P6ligot’s U-tube. The blocks are then united by screws. Upright pieces of wood, of various heights, shaped so as to fit and slide in the channels, can be inserted to give support to the, .U-tubes, or to carry horizontal tubes on their upper, grooved edges. To these pieces the tubes are attached hy spring clips.A trail1 of tube apparatus can thus be held by a single support. M. J. S. Formation of Mixed Crystals. By H. BUHRESS (Bee. TKUZ.. Chim., 10, 57--64).-1. Double Salts of Menm-;c Thiocyanate with Zhc, Cadmium, Cobalt, and Coppel. Yhiocyanates.-The salts having the following compositions, crystallise well :-Hg( CNS)2,Zn(CNS)2 ; Hg( CNS)2,Co(CNS)2 ; 2EIg(CNS)*,Cd(CNS), ; and Hg(CNS),,Cu(CNS), + H,O. The zinc and cobalt double salts are homogeneous c:-ystals, the former colourleis, and the latter deep-blue. The cadmium salts afford analogous, pale-blue crystals, which, in the case of the double salts of zinc and cadmium, are almost identical in forni with those of zinc mercury thiocyanate ; consequently, two double cadmium mercury thiocyanates should exist and correspond with the formuJz 2Hg( CNS),,Cd( CNS), (Nordstrom’s salt) and Hg( CNS,),Cd(CNS ).respectively, which are analogous to the nmmoniiim salts Hg( CNS),,NH,CNS and Hg( CNS)2,!2SH,CNS. Prom the liquid obtained by the addition of mixed solutions of cobalt and cadmium nitrates, or of cobalt and zinc nitratep, to ti very dilute solution of ammonium mercury thiocyana te, colourless needles separate ; these break up on the addition of ammoniuiii thiocyanate, when the mother liquor affords the large, mixed, deep-blue crystals, noted above. No mixed crystals of cobalt and copper compounds could be obtained. With the blue crystals of the cobalt salt, yellowish-green crystals of mercury copper thiocyanate occur, a result the author ascribes to it reaction induced by the water of crystallisation the double copper salt contains.Addition of mercury ammonium thiocyanate to mixed solutions of copper, zinc, cobalt, and cadminm salts, determines the formation of mercury copper thiocyanat,e, and characteristic brown-violet crystals of mercury zinc copper thiocyanate, which contain no cobalt, and are isomorphnus with the zinc compound. These do not alter wbea heated at lYO”, whereas the dark-green needles of mercury copper thiocyauste become dark and opaque. The author concludes that, in presence of much ziiic, meycury copper thiocyanate loses its water of crystallisa- tion yielding mixed cryst~ls with mercury zinc thiocyanate, whereas when mercury copper thiocyanate crystallises alone, it a1 ways con- t:lins a molecule of water of crystallisation.2. Silrer Chromate tcnd Silver SuEphafe.--The small, sed crystaI3, forming the precipitate produced by the addition of potassium dichi-oulate solution to ft silver nitrate solution acidified with nit,&IN0 RGXNIC CHE M ISTR T. It acid belong, like potassium dicliromate, to tht: clinorhombic system. If silver sulphnte he substituted foia silvc r nitrate, the blood-red crystals yielded a t fir4 are monoclinic, but are succeeded by the deposition of oiaange-yellow, orthorhombic crystals of -the mixed salt Ag,S04 + Ag&r04, with liberation of chromic acid. 3. Phosphates a.n.d Arsenates of the type NHdMgPO, + 6H20.- Salts of this type form hcmimorphic ortborhombs. The correspond- ing hemimorphic double phosphates of magnesium, maiignnese, cobalt, and nickel are known, and the anthor has prepared the analogous arsenates of calcium, zinc, and copper.He describes and figures crystals obtained by him in endeavouring to produce mixed crjstnls of these salts: in order to determine if their constitution was of the same type as the magnesium derivative. Although in this resptct his results are not conclusive, ye:f from the developnient of the crystals he concludes thah neither a central point nor a plane of symmetry is necessa1.y to the dovelopmerit of hemimoi-phic crystals, since they originate equally well from a lateral plane or a summit. T. G. N.J O U R X A LOFTHE CHEMICAL SOCIETY.ABSTRACTS OF CHEMICAL PAPERS PUBLISHED INBRITISH AND FOREIGN JOURNALS.General and Physical Chemistry.Refraction and Dispersion of Sodium Chlorate.By F;D WSAUD (C'ompt. rend., 113, 291-292).-The measurements weremade with several different forms of refractometer, but the diverg-ences between the results obtained with different instruments did notseem to follow any definite law. The following are the indices ofrefraction at 2 Y :-a. B. C. n. b. F.1.51097 1.51163 1.51267 1.51510 1.51933 1.52161Cdg. Cd,@ Cd,,. Cd12. Cd,,. Cd 1s.1.53883 1.54242 1.54421 1.54700 1.57203 1.58500The mean variation of the index of refraction is -0*000057 perdtgree, and seems to be practically the same for all the visible rays.C. H. B.Re1 ation between the Index of Refraction, Density, Molecu-lar Weight, and Diathermanous Power of a Substance. ByAYsfoPr'KE'r (Compf.Tend., 113, 418--421).-1f A is tho diathermanousconductivity of a certain substance, A = QMV, where M is the masscontained in unit area of substance of thickness kh, and V is themean relocity. If k isproportional to the thickness a of a molecule, k = CF, where C is aconstant. If the molecule is spherical, E = ( e / d j J , e being themolecu-lar weight. Suppose V = n - I , where n is the index of refraction,thenwhere P is a correction applied on account of reflection.M = kXd, d being the densit'y of the liquid.AY = +Ce4 ds (?a - l)",VOL. LXII. 2 ABSTRACTS OF CHEMICAL PAPERS.The author verifies the above formula by observations with water,alcohol, benzene, chloroform, and carbon bisulphide. H. C.Emission Spectra of Neodymium and PraeseodymiumOxides and of Luminous Solids containing Neodymium.ByL. HAITINGER (MonLitslL., 12, 362-367) -Welsbach found that prseseo-dymium oxide gives a continuous emission spectrum, and neo-dymium oxide a discont'inuous spectruin similar to that noticed byBunsen in the case of didymium oxide. The author confirms Wels-hach's obserrntions with neodymium oxide, iising this oxide mixedwith aluiniiiium oxide for the production of the spectrum. Theliues are found to vary somewhat, both i n intensity and position, oillong-continued heat,ing of the mixed oxides, and also if magnesium issubstituted for aluminium oxide. Prsseodymiuni oxide, which alonel i ~ s no emission spectrum, shows one when mixed with alumiciumoxide. This behaviour mav, perhaps, be explnined by assuming thata higher oxide is fornied when the salt is heated alone, but not whenmixed with other oxides.No emission spectrum was, however,obtained on heating prxwodymium oxide in a reducing atmosphere.The praence of a trace of neodymium i n calcium sulphide causes aphosphorescence, the spectruni of which is similar to the absorptionspectrum of concentrated solutions of neodymium salts.Study of the Chemical Neutralisation of Acids and Bases,by means of their Electrical Conductivities. By D. BERTHELOT(Compt. rend., 113, 261-263).-A summary of the results of theresearches previously published. Potassium hydn)xide, a strong base,with hydrochloric acid, acetic acid, or phenol gives compounds whichhave almost identical conductivities, behave as true salts, are stablein solution, and are not decomposed by water.Ammonia. a feeblerbase, with hydrochloric acid and acetic acid gives stable compounds,b u t with phenol only an unstable compound with a higher resistancethan the normal salts, and, to a large extent, dissociated by water.Aniline, a still feebler base, gives with hydrocliloric acid a stablecompound that is a goad conductor; with acetic acid an unfitablecompound with a considerablj- higher resistaiice ; and u ith phenolonly a lion-conducting mixture without any trace of combination.Experiments with the hydroxybenzoic acids. which unite thefunctions of an acid and A phenol, sliow that, whilst the presence ofthe two functions call be readily recognised, they affect, one anotheiain a manner more or less marked according to their relative positions;in the molecule.C. H. B.H. C.Calculation of the Specific Heat of Liquids. By G. HIXRICHS(Conzpt. rend., 113, 46x3471) .-In the liquid state, molecules rotate~ o u n d the natural axis, for which the moment of inertia is a, minimum.Tf .i is the moment of inertia, M the mass of the molecule, and p theindius of gyration, i = Mpz* The total energs, c, of the molecule ofa liyiiid is the snm of tlie energy of rotntioii and of the potentialenergy, which is a function @ of the absolute temperature T,c = liiT + M@(T) = MeGENERAL AND PHYSICAL CHEMISTRY. 3wherz c = 7;p?l' + @(T), the tot'al energy of unit mass. The specificheat, c, of unit mass will be obtained by differentiation of e withregard to T,c = K(rZ + @'(T).The author sbows that a formula of this kind holds i n the case ofthe ethereal salts of the fatty acids, taking Schiff's observations of thespecific heats of salts of this series. H.C.Second Law of Thermodynamics and its Application toChemical Phenomena. By H. LE CHATELIEE (Bull. SOC. Chilit.[3], 5, 837--840).-Carnot's principle is directly applicable tochemical changes, if all restriction as to the natnre of the equilibihmcstablished by the change is removed. Tlie same reasoning which isapplied to the eshblishment of heat equilibrium may then be appliedTO chemical eqnilibrium. The available energy obtainable from twodifferent states of the sajme system will be the same for all reversibletrausformations of the one state into the other, arid independent ofthe means emploped f o r rendering this energy available, and will begreater for reversible t h a n for non-reversible transformations.Theauthor shows how from this principle mty b e deduced, in a vergsirriple manney, the iaws of isodissociation which he formerly ob-tained by a far more complicated process-starting from the t w oH. c.New Isot3errhal Curves for Carbonic Anhydride. By E. H.AblAGaT (Conyx!. rend., 113, 446--451).-The author has determinedthe isotliermals f o r carbonic anhydride for every 10" from 0" t o loo",and also for the temperatures 32", 35", 137", 198", and 258'. Thepressures were taken up to 1000 atmospheres, and the method em-ployed was that described in former communications. The results aregiven in t;lbuli\r form, and the isothermal curves for each of thetemperatures taken.The following table is given f w the pressures ofliquefaction of carbonic anhydride a t the temperatnres under ex-amiriatioii :-cquivalent principles of Clausius.Temperature.. .. .. . . . . .. . . .. 0" 10" 20' 30"Pressure in atmospheres ,. . . . 35.4 44.4 56.4 70.7The full discussion of the results is reserved for a future paper.Heat of Formation of Platinic Bromide and its principalCompounds. By L. PIGEON (Cornpi. rend., 113, 476--479).-Pla-tinic bromide, prepared hy carefully heating hydrogen platinic brorn-ide, was dissolved in water, 9.86 Cal. being developed. The solutionwas then reduced by metallic cobalt, the heat developed beingi13.59 Cal.By subtracting tlie heat of formation of the cobaltbromide, 145.88 Cal., we get for the heat of formation of dissolvedplatinic bromide 32.29 Cal., and from this the heat of formation ofthe solid salt, 42.43 C d . Solid plaqinic bromide dissolved in hydro-biwrnic acid solution (1 mol. in 4 litres; gives rise to a developmentof 19.27 Cal., from which the heat of formation of a solution r,fH. c.b 4 ABSTRACTS OF CtEEMMICAL PAPERS.hydrogen platsink bromide from platinum, bromine, and hgdro-bromic acid is 60 7 0 Cal. The formation of the crystalline saltH,PtBr, + 9H,O is attended by the development of an additional2.86 Cal.The author draws attention to the fact that the heats of fornia-tion of the compounds of p7atislnm nzld bromine are, when gaseoushromine is taken, very nearly-equal to the heats of formation of thesimilar compounds of platinum and chlorine.€3. c.Heats of Combustion and Formation of Nitrobenzenes. ByBERTHELOT and MATIGXOX (Compt. ~ e ~ z d . , 113, 246-249) :------Ortbodinit rohenzene. ...........Met,adinitrobenzeiie ............Paradinitrobenzene ............Tiinitrobenzene (1 : 3 : 5 ) . ......Trinitrobenzene (1 : 2 : 4). ......Heat ofcombus-tion,conutiintvol urn e .Cnl. + 704 -6 + 698.1 + 696 -5+ 665.9 + 680 -6--Heat ofcombus-tior.,constantpressure.Cal.+703 5 + 697 ‘0 + 696.4+ 663 ’8 + 678 ‘5--Forma-tion fromelements.--Cal .+ 0 . 5+6.8+8*4+ 5 .5- 9 . 2Forrna-tion fromnitric acid,---Cal. + 58 -3 + 64 ’8 + 66 4+ 90.9t- 76 ‘ 2It is clear that although the ralucs for t,he various isomeridesare very similar, as i s usually the case, there are distinct diflerences,amounting to 1 per cent. in the case of the dinitro-derivatives, andto 2 per cent. in the case of trinityo-derivatives. The differencesare also distinct in the case of the formation from nitric acid, andthe heat deyeloped becomes less the niore advanced the substitution.The heat of formation of a nitro-derivative is always but slightlydif-ferent from that of the generating hydrocarbon ; and i t follows thatthe oxygen of the iiitroxyl group has nearly the same combustiblepower as if it were in the free state.Since the heah of formationbecomes less as nitrakiorn advances, it follows that the combustibleenergy of the ox-j-gen gradually increases. The hearing of thisresult on the explosibility of nitro-derivatives is obvious.Calorific Value of Food Constituents and their Derivatives.By I!. STOHMAKX’ aiid H. LANGBEIX (J. pr. Chern. [2], 44, 336-399).--Stohmatin is surprised that Berthelot (Ann. Chiin. Phys. [GI, 22, 5)has not, quoted him as an authority on the thermochemistry ofprotei’ds and made use of his work on the subject (compare Abstr.,1885, 85’7).The authors have already dealt with the calorific values of animalfats (Abstr., 1831, 11) ; in this paper they summarise the calorificvalues which they obtain for various prote‘ids and the products of theirchange.Full data for the results, and details as to source of thecompounds, are given. The following tables summarise the valiies,C. H. R*pc----N l a h i i .................Vegetable iibi*iii.. ........Serum albumin ..........Yynlonin.. ..............H ze inoglo hin ............%[ilk w ~ e ' h , No. 1 . . ...... .. No. 2 . . ......yolk of egg.. ............Leguinin ................Vitellin .................u albu1nit~ ............ %& Elesh fibre, No. 5 ........Crystallised dbun\iii.. ....Flesh, No. 3 ............ .. 3 0 . 1 ............Blood fibrin .............hwiiack's albumin .......Wool fibre ..............Conglutin. ..............Skin fibroh.. ............Yelit one ...............>Cliotidrin ...............Oaaein ..................Fibt.o.:n.................Chitin.. ................Calorificvalue pergrain, cal.--5961 '35941 *65917 -85907.85885 -15867 -0584!) '65840.95793 *15745 '15735 '25720 -55672 05662 -65640 '95637 * 15553 *o5510.25479 -05355 -15298 851 30 *65039 *!I4979.64 650 '3Carbon.55 '0354 '3953 *9353 *6454 -7354 *025 4 *1453 -5053 -3250 *275'5 -9552.1151 -4852.0258.9350 -6950 -2050.1849 -9250.1049 *1448 '6348-6345 '15-Hydrogen.7 '206 '987-657 -4.4.6.067 *336 -857.317 -177 .go7 '507 *lo6-767.307 '166 *686 -726 *745 '766 -456 -676.646.086 -4---U1 t iinat,e coin posit ion.Nitrogen.16 -9115 -3915 '1515.7616 -5015 *5215 '6115 '2615 '1.816'0415 -1916 '4418' 1416 '3816 '3616'7214.5 116 '5417 '5118 -0116'4215 '3746.3418 *97---6 -86(?)Sulpli iir.---0.181 '021 '181 -090 '460.750.781'110 '463'091'521 '030.961 '091'011-131 '893 *700 *790'301-241 *260 *95-6 LBSTRACTS OF OHlEMICAL PAPEHS.the atomic proport,ions in Table I being calculated to 720 carbonatoms to avoid decimals ; 72 is the proportion of carbon atoms foundi n white of egg by Liebci-kuhn.Glycocine .. . . . .Alanine . . . . . . . .Leucine.. . . . . . .Barcosine . . . . . .Hippuric acid.. .Aspartic acid, . .Urea . . . . . . . . . .Asparagine. . . . .Xreatine (cryst.)Kreatine (an-hydrous).. . . .Uric acid . . . . . .Guanine . . . . . . .Caffe’ine . . . . . . .-Mol.weight .7589131891’19133601321 49131168151194Calorificvalue..---Cul.234.6387 ‘7855 -8401 -21014 ‘5385 -2152 -2463 *5553 -3560 -0460’5586 *61014.9-Heat offorma-tion.--Cal.125 -9135 8156.7122.3142 -0232 a 379 -8188 -5202 -2126 5198 -555 *982.1Calorificvalue tic-:ording t oBerthelotGal.234.9389 ‘0857.11012 ‘9386 .8151 -5448.1------461 *4----B and A.Band A.B and A.B and A.Band A .Band P.B and A.M.B and A = Berthelot and Andr6, B and P = Bertlielot and Petit, M =Matipon.In connection with the first of these tables, the authors give anothertable showing the results which were obtained by Berthelot andAndre for some of the prote‘ids in the authors’ table; this tableappears to be quoted from Ann.Chim. Phys. [S], 22, 25, which con-tains the same table as appears in Abstr., 1890, 937, but the numbersgiven here do not quite agree with those in the table referred to.If the valnes for elastin, wool-fibre, skin-fibroyn, chondrin, ossein,fibro’in, and chitin be excepted, the mean calorific value for tt eprote‘ids given in the first table is 5730.8 cal. Berthelot (Abstr.,1E90, 938) found 5691 cal. for this number ; the authors regard themean, 5i11 cal., as representing the real value. This value would begiven by the formula C720H11G1NlbiS502L38 ; Lieberkiihn’s formula isFrom the values given in the second table, the authors deduce the fol-lowiug generslisations :-(1) The substitution of CH, for a hydrogenatom in homologous series increases the calorific value by 156-157 Cal.(2) The calorific r a l ~ i e of a methyl group ahtached to a nitrogenatom is higher than that of one attached to a carbon atom.(3) Thedisplacement of a hydrogen atom in A CH, group hy NH, raises thecnlorific value by 26.9 Crtl. (4) The displacenient of tbe hgdroxyl ina carboxyl group by NH, raises the calorific value by 78.6 Cal. Theheat of combustion of carbnnic acid deduced from that of urea bymeans of this peneralisation is -5.0 Cal. Lnnguinine (Ann. Chia?.Il’hys. [S], 8, 133) found -4.3 Cal.and -10.75 Gal. for this number.GH,iaN,tSOmA. G. BGENERAL AND PHYSICAL CHEMISTRY. 7Maximum Density of Water. By H. N. VERSON (PhiZ. MU,^.[ S ] , 31, 337--392).-The author investigated the rate of cooliiig ofquantities of water from 30" down to 0". His thermometer was readto 0.01" by means of a cathetometer. When the water waq notPtirred, there was a sudden break in the cooliiig curve about 4*7",which is therefore to be considerecl tlie point of maximiim density.No bre*ak appeared when the water was stirred, the natural convec-tion currents not then having free play; but from the form of thecurve it would seem that the specific heat of water between 0" find12' is about 3 per cent. greater than between 16" and 30". Both theincreased specitic heat and the maximum density are considered bythe author to have their cause in an aggregation of (H,O)? moleculesto (H20), molectiles about 4" as the water cools.J. W.Expansion of Water. By C. SCHEEL ( C h m . Centr., 1891, ii,409-410 ; Inaug. Diss., Bedin).-The author has determined theexpansion of water between 0" and 33" by means of a glass apparatuu,the volume being read off on a capillary tuhe. (For a completedescription of it, see the original paper.) The absolute expansion ofwater was found to be 0.0408059, tlie minimuni being a t 4~0.38".Dilatation of Phosphorus and its Change of Volume at theMelting Point. By A. LKDUC (Cornpt. rend., 113, 259--%1).-Phosphorus expands almost regularly up to its melting point, whichis M.2" on the mercurial theimometer, aiid 44.1" on the normal ther-mometer.A t this point, without any appreciable change OF tempera-ture, there is a considerable expansion, tlie ratio of the volunie of thesolid phosphorus to that of. the liquid phosphorus bein:,. 1 : 1.0345.Kopp's number was 1.0:343.The expansion of either solid or liquid phosphorus can only berepresented by a formula with three terms, but the abthor is not ableto state the coefficients precisely. The value of the mean coefficientson the normal thermometer between 0" and 44.1" is 0*00037:', acllbetwoen 26' and 50°, 0.000560, the latter being calculated on ttievolume a t 0". These values differ considerably from those given byKUPP. C. H. B.Capillary Constants of Salts at their Melting Points.ByJ. '~'RAURE (Ber., 24, 3U74-:3080).-l'he author has determined thecapillary constants of a large number of salts at temperat,ures justabove their melting points. The method adopted was that of weigh-ing the drops which fell from a single perforation in ft emnll disc thatformed the end surface of a short cvliiider let in to the bottom of i Lplatinum or porcelain crucible. This crucible was so heated, bymeans of an ordinary gas flame or by the blowpipe, that the flame didnot come in contact with the hanging drop. The salts investigatedwere potassium and sodium salts, and the ratios (T) of the weight ofthe drops to the weight of the water-drop at 0" from the same vesselare tabulated.From his results, the author deduces the following conclusions :--Capillarity may be considered a '' colligntive " property.The con-J. W. LB ABSTRACTS OF CHEMICAL PAPERS.stants for the salts of the fatty acids are unusually small, diminishingrapidly as the series is ascended. For the otheio salts the constants(T) of the potassium salts of monobasic acids lie between 112 and157; of bibasic and multibasic acids, between 168 and 231. Thelimits for the constants of the corresponding sodium salts are123-16!, and 189-325. The difference T,, - T, incveases withthe number of cquivalents of the metal in the salts. It is doubtful iftri- and quadri-basic acids can, in this way, be distinguished frombibasic acids, but the author considers it always possible to distinguishbetween the latter and monobasic acids.The method points tothe following formuh as being correct :-K2FZ, KZPZO,, Na3P206,K2 As~O,~. J. W.Mutual Solubility of Salts in Water. By W. W. J. N~cor,(Phil. Mag. [ 5 ] , 31, 369--387).-Uiider the heading '' The MutualSolubility of Salts," the author groups the phenomena due to tJhemutual influence of two salts on each other's solubility in water. IIegives an historical survey of t h e work done on the subject, and pro-ceeds to communicate his own experiments on the chlorides andn ttrates of sodium and potassium taken in all possible combinationsof pairs with a common constituent. The method of experimentadopted was as follows :-A salt was taken, ant1 solutions containing1, 2, &c., gram-mols. of this salt in 100 gram-mols. of water wereprepared.These solutions w e i ~ then satuixted ilf a detinite tempera-ture with the other salt added in excess, and the total salt in solutiondetermined. Precisely similar determinations were made with definiteniolecular solutions of the other salt. The solnbility of each saltseparately i i i water was then determitied, and finally, the solubility ofboth salts when simultaneously added in excess to water was alaoascertained.'l'he results are presented in the form of tables, formulae, and curves,In general, the presence of one salt diminishes the solubility of theother, but i n the case of the nitrates of potassinm and sodium, t h epresence of the one in solution increases the solubility of the other..(Compare Nernst, Abstr., 1890, 3 ; Le Blaric and Noyes, Abstr.,18131, 388.) J.W.Cryoscopic Behaviour of Dilute Solutions. By J. TRAURE(Ber., 24, 3071-3074).-Eykrn:tii1i and Arrheriius have pointed out,(Abstx., 1891, 972 and 1148) that the observations of the auihor onthe freezing point of dilute. solutions, in particular of those of canesugar, are not i n accordance with their own experiments, o r w i t hthose of Tanimann end Pickering. The author upholds his numbers,and attributes the discrepancy to the other observers having cooledtheir solutions too far below tne freezing point before making ohser-vations. J. W.Automatic Replacement of Mercury in Sprengel Pumps.By A. VEIINEUIL (ULIIZ. Soc. Chim. [ ; 3 ] , 5, 748---750).-'l'lie mercuryis cmntiiiuously and automatically transferred from the lower to theupper reservoir by t h e action of n water-pressure or similar piirnpGENER1.L AND PHYSICAL CHEMISTRY.9tlie suction.tube of which is attached to the upper end t of a smallbulb, connected by tubes a, b to both reservoirs, and placed about40 cm. above the upper one. The contents of the lower reservoirare thus forced into the bulb by atmospheric pressure, and allow-ccl tofnil into the upper reservoir by their own weight. The tube a is3 mm. in internal diameter, and is recurred at the lower end, the levelof the mercury at that poiIit being so adjusted that much air and littlemefcury passes up the tube; the tube b is 6 mm. ininternal diameter.It. isnot intended to be used at starting, as it is found niorc convenient totransfer any considerable quantity of mercury by hand than to makethe apparatus of unnecessarily large dimensions.An incidentaladvant,age is t h a t the mercury is bronglit into contact with airunder conditions favourable to the oxidation of impurities.The a.pparatus is applicable to most existing mercury pumps.JN. W.Block Support for Tubes. By A. GAWALOVSKI (Zeit. anal.CItern., 30, 581-583).-Two elongated blocks of hard wood, laid sid10 ABSTRACTS OF CHEMICAL PAPERS.by side, have rectangular grooves ploughed in their contiguous faces,so as to form a channel, the cross section of which corresponds,approximately, with the shape of the bulbs of R P6ligot’s U-tube.The blocks are then united by screws. Upright pieces of wood, ofvarious heights, shaped so as to fit and slide in the channels, can beinserted to give support to the, .U-tubes, or to carry horizontal tubeson their upper, grooved edges.To these pieces the tubes areattached hy spring clips. A trail1 of tube apparatus can thus be heldby a single support. M. J. S.Formation of Mixed Crystals. By H. BUHRESS (Bee. TKUZ..Chim., 10, 57--64).-1. Double Salts of Menm-;c Thiocyanate withZhc, Cadmium, Cobalt, and Coppel. Yhiocyanates.-The salts havingthe following compositions, crystallise well :-Hg( CNS)2,Zn(CNS)2 ;Hg( CNS)2,Co(CNS)2 ; 2EIg(CNS)*,Cd(CNS), ; andHg(CNS),,Cu(CNS), + H,O.The zinc and cobalt double salts are homogeneous c:-ystals, the formercolourleis, and the latter deep-blue. The cadmium salts affordanalogous, pale-blue crystals, which, in the case of the double saltsof zinc and cadmium, are almost identical in forni with those of zincmercury thiocyanate ; consequently, two double cadmium mercurythiocyanates should exist and correspond with the formuJz2Hg( CNS),,Cd( CNS), (Nordstrom’s salt) and Hg( CNS,),Cd(CNS ).respectively, which are analogous to the nmmoniiim saltsHg( CNS),,NH,CNS and Hg( CNS)2,!2SH,CNS.Prom the liquid obtained by the addition of mixed solutions ofcobalt and cadmium nitrates, or of cobalt and zinc nitratep, to ti verydilute solution of ammonium mercury thiocyana te, colourless needlesseparate ; these break up on the addition of ammoniuiii thiocyanate,when the mother liquor affords the large, mixed, deep-blue crystals,noted above.No mixed crystals of cobalt and copper compounds could beobtained.With the blue crystals of the cobalt salt, yellowish-greencrystals of mercury copper thiocyanate occur, a result the authorascribes to it reaction induced by the water of crystallisation thedouble copper salt contains.Addition of mercury ammonium thiocyanate to mixed solutions ofcopper, zinc, cobalt, and cadminm salts, determines the formation ofmercury copper thiocyanat,e, and characteristic brown-violet crystals ofmercury zinc copper thiocyanate, which contain no cobalt, and areisomorphnus with the zinc compound. These do not alter wbea heatedat lYO”, whereas the dark-green needles of mercury copper thiocyaustebecome dark and opaque. The author concludes that, in presence ofmuch ziiic, meycury copper thiocyanate loses its water of crystallisa-tion yielding mixed cryst~ls with mercury zinc thiocyanate, whereaswhen mercury copper thiocyanate crystallises alone, it a1 ways con-t:lins a molecule of water of crystallisation.2. Silrer Chromate tcnd Silver SuEphafe.--The small, sed crystaI3,forming the precipitate produced by the addition of potassiumdichi-oulate solution to ft silver nitrate solution acidified with nit,IN0 RGXNIC CHE M ISTR T. Itacid belong, like potassium dicliromate, to tht: clinorhombic system.If silver sulphnte he substituted foia silvc r nitrate, the blood-redcrystals yielded a t fir4 are monoclinic, but are succeeded by thedeposition of oiaange-yellow, orthorhombic crystals of -the mixed saltAg,S04 + Ag&r04, with liberation of chromic acid.3. Phosphates a.n.d Arsenates of the type NHdMgPO, + 6H20.-Salts of this type form hcmimorphic ortborhombs. The correspond-ing hemimorphic double phosphates of magnesium, maiignnese, cobalt,and nickel are known, and the anthor has prepared the analogousarsenates of calcium, zinc, and copper. He describes and figurescrystals obtained by him in endeavouring to produce mixed crjstnlsof these salts: in order to determine if their constitution was of thesame type as the magnesium derivative. Although in this resptcthis results are not conclusive, ye:f from the developnient of thecrystals he concludes thah neither a central point nor a plane ofsymmetry is necessa1.y to the dovelopmerit of hemimoi-phic crystals,since they originate equally well from a lateral plane or a summit.T. G. N