CHEMISTRY. 



85 



and is, like gold, only attacked by aqua regia 

 and those fluids which generate chlorine ; it is 

 moreover unaffected by sulphuretted hydrogen 

 or any of the hydrosulphurets, and as a paint 

 is practically imperishable. 



Its composition appears to be very peculiar, 

 though a sufficient number of analyses has not 

 yet been made to settle that question beyond the 

 range of doubt. Nevertheless, it seems to con- 

 sist of one atom of mercury (202), three atoms 

 of sulphur (48), one atom of carbon (6), and 

 one atom of hydrogen (1) ; thus making 257 as 

 its atomic equivalent, and leading us to con- 

 clude that it is a hydro-erythride of the proto- 

 sulphuret of mercury, whence we may infer 

 that it might be made by a very different pro- 

 cess to that above described, and, indeed, we 

 may naturally expect many improvements in 

 the mode of its production. 



As we have seen, the first effect of passing 

 coal-gas through an alkaline solution of bicya- 

 nide of mercury is a white precipitate. If we 

 arrest the process at this point we obtain, in the 

 usual way of washing and drying, a gray-white 

 powder, which on applying heat explodes with 

 great violence. In all probability it consists 

 of two substances, one containing sulphur and 

 the other cyanogen united to some form of 

 hydrocarbon ; it is to this last that the name 

 " cyanon " has been provisionally given. 



As procured in the way described, cyanon is a 

 white powder having a greenish-gray tint, and, when 

 a few grains of it are heated in a test-tube, it ex- 

 plodes at a heat of about 400 Fahr. with much 

 force and the production of a considerable quantity 

 of soot or carbon, while the mercury is thrown out 

 of the tube to a considerable distance, so that cya- 

 non may truly be said to combine the qualities of 

 both gunpowder and shot. The cyanogen com- 

 pound, which in cyanon is united to mercury, has 

 been transferred to copper with the production of a 

 copper salt having an explosive quality quite equal 

 to the mercurial compound; and in all likelihood 

 this copper salt is the substance which has fre- 

 quently caused explosions during the repairing of 

 old gas-meters by soldering them. This explosive 

 quality is, however, destroyed by the action of hy- 

 drosulphate of ammonia, and no doubt common gas- 

 liquor would answer the same end, so that it would 

 be a wise precaution to bathe old gas-meters in gas- 

 liquor before attempting to apply a heated soldering 

 iron to them. 



To obtain cyanon it is not necessary that there 

 should be an excess of caustic alkali present in the 

 liquor, for this is needed only to insure the forma- 

 tion of ponsselion ; consequently we have merely to 

 boil a solution of the cyanide of potassum upon an 

 excess of peroxide of mercury, and, after filtering 

 the cold liquor, pass a current of purified coal-gas 

 through it until a sufficient quantity of white precip- 

 itate has been formed, which must then be washed 

 and dried in the usual way. 



New Compounds of Chromium and Manga- 

 nese. A paper of considerable interest in 

 theoretical chemistry was communicated to 

 the Glasgow Philosophical Society by J. B. 

 Hannay, on certain new compounds of chro- 

 mium and manganese. He observes that, on 

 examining any general list of carbon com- 

 pounds, however complicated their structure, 

 they are not as a rule decomposed by water ; 



on the other hand, complex compounds of 

 other elements are as a rule decomposed by 

 this substance into two or more simpler com- 

 pounds. Mr. Hannay was therefore induced 

 to examine whether carbon is or is not the 

 only element capable of forming series of 

 bodies of complicated structure ; and whether 

 the existence of water on this earth is the 

 reason of our not having complex bodies with 

 other elements than carbon for their basis. 

 The plan adopted was to take some compli- 

 cated substance containing no carbon which is 

 decomposed by water, find a solvent for it, and 

 act on it with other reagents out of contact of 

 air and moisture. The substance used was 

 oxychloride of chromium (CrO 2 Cl 2 ), and the 

 solvents employed were carbon disulphide and 

 carbon tetrachloride. Mr. Hannay has devised 

 an apparatus which allows of the substance 

 being precipitated, filtered, washed, dried, and 

 weighed off for analysis without coming in 

 contact with air or moisture. The following 

 is a list of the chromium compounds prepared 

 by him : 



Cr 2 Cl 4 S0 3 . Cr 4 Cl 6 S 3 . Cr 3 Cl 6 P 2 Br 6 O . 



Cr 2 Cl 4 S0 2 . O 4 C] 6 S 3 4 . Cr 3 Cl 6 P 4 6(H 2 0). 



Cr 2 Cl 4 Br 2 . Cr 4 Cl 6 S 3 Oi 2 . Cr 3 Cl 6 P 4 . 



Cr 2 Cl 4 S 2 2 . CrCl 2 S 2 H 2 0. Cr 3 Cl 6 PCl. 



Cr 2 ClS. CrCl 2 S 2 . O 3 Cl 8 PBr. 



Cr 2 Cl 4 Br 2 S. CrCl 5 PSO. (Cr 3 Ol 6 P) 2 O. 



Cr 2 Cl 4 S 2 . Cr 3 Cl 6 P 4 6 . Cr 3 Cl 6 P. 



Cr 3 Cl 6 P 4 2 . 



Mr. Hannay has prepared some analogous 

 manganese compounds, but the analyses of 

 these have not yet been finished. 



The Luminosity of Flame. Heumann con- 

 siders the luminosity of hydrocarbon flames to 

 be due to the presence in them of solid parti- 

 cles of incandescent carbon. The grounds on 

 which this opinion is based are thus briefly 

 summed up in the "American Journal of Sci- 

 ence " : "1. The increased luminosity which 

 chlorine gives to weakly luminous or non-lumi- 

 nous flames is due to its well-known property 

 of separating the carbon as such. 2. A rod held 

 in a flame is smoked only on the lower side, 

 the side opposed to the gas stream. Were the 

 carbon there as vapor, as Frankland assumes, 

 it would be condensed by a cooling action, and 

 so all around the rod. 3. A body held in the 

 flame is smoked even when it is in a state of 

 ignition ; this, therefore, can not be conden- 

 sation of a vapor 4. These particles can be 

 actually seen in the flame when it is made to 

 strike against a second flame or an ignited 

 surface, the particles aggregating together to 

 form visible masses. 5. The luminous portion 

 of a flame is not very transparent, no more so 

 than the layer of smoke of the same thickness 

 which rises above a flame fed with turpentine. 

 6. Flames which unquestionably owe their lu- 

 minosity to the presence of solid particles give 

 a shadow with sunlight, precisely as do hydro- 

 carbon flames; while luminous flames com- 

 posed only of ignited gases and vapors give no 

 such shadow in sunlight." 



Alum in Baking-Powders. Dr. Henry A. 



