CHEMISTRY. 



105 



coq de Biosbaudran estimated its atomic weight 

 from two characteristic lines in the spectrum 

 at72'31 or 72-27. The position of germanium 

 is that of ekasilicon in Mendelejeff's table, for 

 which he predicted an atomic weight of 72 and 

 specific gravity of 5 '5. The specific gravity 

 of germanium is 5'469. This position is more 

 conclusively indicated by two of the com- 

 pounds of germanium prepared by Dr. Wink- 

 ler. The first is germanium-chloroform, GeH 

 Cls, analogous to the similar compounds of 

 carbon and silicon, which is obtained by gently 

 heating germanium in a stream of dry hydro- 

 chloric-acid gas. The second is germanium 

 ethide, Ge (CH 6 )4, analogous to the ethides 

 of silicon and tin, which is obtained by the 

 action of two volumes of zinc ethide upon 

 one volume of germanium tetrachloride. This 

 disposes of all doubt that the gap in the pe- 

 riodic table must be occupied by germanium, 

 for Dr. Mendelejeff predicted that the metal 

 thus filling up this particular gap would be 

 found to form, if discovered, a tetra3thide ot 

 specific gravity about 0-96, and boiling at 160 

 conditions which germanium ethide fulfills. 



A fine series of new coloring-matters has 

 been discovered by Dr. J. H. Siegler, by the em- 

 ployment of the hydrazine reaction upon ami- 

 do-derivatives of triplienyl-methane. Rosani- 

 )>Njie hydrochloride was first converted by ni- 

 rous acid into its diazo-derivative, and this 

 was then reduced with tin and hydrochloric 

 acid, yielding brilliant green crystals of a hy- 

 drazine salt. This new hydrazine, which the 

 discoverer terms roshydrazine, is itself a color- 

 ing-matter of a somewhat bluer shade than 

 fuchsine, and forms the nucleus of the series. 

 By treatment with aldehyde, acetone, or ben- 

 zophenone, condensation products are obtained 

 possessing brilliant colors, varying from red to 

 violet ; benzaldehyde and aceto-acetic ether, 

 yield beautiful blues ; while grape-sugar forms 

 with roshydrazine a dye of a greenish-blue 

 tint. Numerous shades are further produced 

 by the action of other reagents. The sulpho- 

 derivative of roshydrazine appears to form a 

 second series of colored substances quite as 

 numerous as those of the nucleus itself. These 

 new colors are practically insoluble in water, 

 and a fact of most vital importance about them 

 is that they may be readily prepared in situ 

 upon the fiber ; for it is only necessary to im- 

 merse the material first in a bath of roshydra- 

 zine, and afterward in a second bath contain- 

 ing the condensing reagent. 



Mr. Gary Lea has published a series of papers 

 to show that chlorine, bromine, and iodine are 

 capable of forming compounds with silver ex- 

 hibiting varied and beautiful colors peach- 

 blossom, rose, purple, and black ; that these 

 compounds (except under the influence of light) 

 possess great stability; that they may be ob- 

 tained by purely chemical means, and in the 

 entire absence of light ; that of them the red 

 chloride shows a tendency to the reproduc- 

 tion of colors. It is not improbable that the 



material of the infinitesimally thin films ob- 

 tained by Becquerel, Niepce de St. Victor, 

 Poitevin, and others, may be the red chloride ; 

 and that these substances, formed by purely 

 chemical means, constitute the actual material 

 of the latent invisible photographic image, 

 which material may now be obtained in the 

 laboratory without the aid of light and in any 

 desired quantity. They also form part of the 

 visible product resulting from the action of 

 light on the silver haloids. The salts thus 

 produced are called by the author photo-salts, 

 because of their identity with theproductsof the 

 action of light on the normal silver haloids. 

 Mr. Lea concludes from the results of his ex- 

 periments, that the latent photographic image 

 consists neither of the normal silver haloid 

 modified nor of a subsalt, but of a combination 

 of normal salt and subsalt ; that the salt loses 

 in this way its weak resistance to reagents, 

 and acquires stability, thus corresponding to 

 the great stability of the latent image, which, 

 though a reduction product, shows consider- 

 able resistance to even so powerful an oxidizer 

 as nitric acid ; further, that this combination 

 of normal salt and subsalt, which constitutes 

 the material of the latent image, can be ob- 

 tained by chemical means, and wholly without 

 the aid of light ; that the forms of the photo- 

 salts which correspond to the material of the 

 latent image are colorless or nearly so, but 

 that other forms, possessing beautiful and often 

 intense coloration, also exist. "With the chlo- 

 ride some of these brightly-colored forms show 

 a ready tendency to reproduce color, in some 

 cases with well-marked and beautiful tints. 

 " So that we have here an approach to the 

 solution of the problem of obtaining images of 

 objects in their natural colors from a quite new 

 direction, and probably with better hopes of 

 an eventual complete success than by any of 

 the older methods." 



A new preparation, salol, or phenolsalicylic 

 acid, offered by Professor Rencki as a substi- 

 tute for the unpleasant specific salicylate of soda 

 in rheumatic disorders, has found a ready mar- 

 ket. The new compound is as valuable as an 

 antiseptic and antipyretic as in its more special 

 application. It is a white, crystalline powder, 

 having a weak aromatic odor, but perfectly 

 tasteless, insoluble in water, but easily soluble 

 in alcohol and ether. The pure preparation 

 melts at 42 or 43 0., and is not colored by 

 chloride of iron, which stains its components, 

 phenol or carbolic acid, and salicylic acid 

 deep bluish green or violet. It is prepared 

 by heating molecular proportions of salicylate 

 of soda and phenol-soda with chloride of phos- 

 phorus. Salol is perfectly harmless in its ef- 

 fects on the system, and is used in the same way 

 as the salicylate of soda. 



The theory that microbes are the primary 

 sources of disease has been qualified by the 

 discovery that certain alkaloids which act as 

 violent poisons are the immediate result or ac- 

 companiment of bacterial fermentation. Brie- 



