332 Scientific Intelligence. 



within one five hundredth of the whole. Each impurity behaves 

 as if it alone were present. — C. JR.\ cxiii, 531 ; J. Chem. Soc, 

 lxii, 236, February, 1892. G. f. b. 



3. On certain Metallic Hydrosulphides. — On critically examin- 

 ing certain metallic sulphides precipitated in the ordinary way, 

 Linder and Picton found that they contained combined hydro- 

 gen sulphide, forming in some cases definite and stable com- 

 pounds. Moreover, higher hydrosulphides were also obtained, of 

 high molecular mass, which under the influence of acids undergo 

 condensation with elimination of hydrogen sulphide and which 

 form solutions of moderate strength. When neutral solutions of 

 certain metallic salts are allowed to run into a solution of hydro- 

 gen sulphide in excess, a solution is obtained, clear by transmitted 

 light, which in some cases can be freed from its uncombined 

 hydi'ogen sulphide by a current of hydrogen without causing 

 precipitation. Acids, however, and metallic salts of inorganic 

 acids, caused precipitation. To eliminate the production of acids 

 the metallic hydrates or sulphides suspended in water were 

 treated with hydrogen sulphide and solutions were obtained 

 which were clear by transmitted light although strongly fluores- 

 cent. The authors conclude (1) that almost all the metals pre- 

 cipitable by hydrogen sulphide are capable of forming hydro- 

 sulphides, (2) that in some cases they are definite compounds 

 fairly stable though of high molecular mass, (3) that acids cause 

 these hydrosulphides to lose a part of their hydrogen sulphide, 

 thus producing compounds of progressively higher molecular 

 mass, (4) that by dissolving the precipitated sulphides in hydro- 

 gen sulphide water solutions are obtained which show no ten- 

 dency to deposit any precipitate even after months of standing, 

 (5) that these experiments support the conclusion that sulphides 

 themselves are in most cases polymerides of a very high molecu- 

 lar mass, (6) that hydrosulphides of copper (CuS) 7 . H„S, (CuS) 9 . 

 H 2 S, (CuS)„ 2 . H„S, and hydrosulphides of mercury (HgS) 91 . H„S 

 and (HgS) 62 .H 2 S have actually been obtained, and (7) that 

 bismuth seems incapable of forming a hydrosulphide. — >T. Chem. 

 Soc, lxi, 114, February, 1892. G. f. b. 



4. On the Physical Constitutions of certain Sulphide Solu- 

 tions. — PiCTOiSj" has submitted the hydrosulphide solutions, ob- 

 tained as above, to a careful examination in order to test the 

 question whether they are actual solutions or whether they con- 

 tain the solid only in a very fine state of suspension. An arsenide 

 acidified with hydrogen chloride and the liquid allowed to run 

 into hydrogen sulphide water, readily gives a solution containing 

 about five grams of sulphide in the liter; while in the case of 

 mercuric sulphide thus treated, the solution contains ten grams to 

 the litei\ Examined with the microscope, under a power of 1000 

 diameters, the entire field is seen to be filled with exceedingly 

 minute particles in very rapid Brownian movement. On filtra- 

 tion through a porous cell, the liquid came through colorless. 

 Two solutions were obtained with arsenic; one (a) prepared by 



