506 



Mr. G. S. Johnson. 



(b.) 1-3302 grams of Hg salt gave 01522 gram H 2 0. 



and 0-4187 „ C0 2 . 

 Equivalent to 0*01681 1 gram of hydrogen, 

 and 0*114191 ,, carbon. 



Hence Hg salt contains ( h ^ r0 ^'i' 26 P er cent ' 

 1 carbon, 8*584 



The nitrogen was estimated in this compound and in all the 

 analyses recorded in this research by a modification of Dumas' method. 

 The substance to be analysed is introduced in a boat behind the copper 

 oxide, instead of being mixed with the latter. By this means the 

 copper oxide can be ignited strongly in a stream of carbon dioxide, 

 before adjusting the measuring tube for the nitrogen. Residual 

 carbon left in the boat at the end of the combustion is burnt off by 

 oxygen generated by heating potassium chlorate in a second boat 

 placed behind that which contains the substance to be analysed. 



The following results were obtained : — 



(a.) 0-7728 gram of Hg salt gave 44'83 c.c. of nitrogen, measured 

 at 0° 0. and 760 mm. P., equivalent to 0*0560385 gram of N. 

 Hence the Hg salt contains 7*25 per cent, nitrogen. 

 (6.) 0*6228 gram Hg salt gave 36*29 c.c. of nitrogen, measured at 

 0° C. and 760 mm., equivalent to 0*0453625 gram of N". 

 Hence the Hg salt contains 7*28 per cent, of TS". 



The mercury was determined in two ways : 1st, by dissolving the 

 Hg salt in HC1 and precipitating the solution by H 3 S ; and 2ndly, 

 by suspending the Hg salt in water and decomposing by H 2 S. The 

 close concordance between the results proves how very completely the 

 mercury salt may be decomposed by hydrogen sulphide under water. 



(a.) 1'0882 gram of Hg salt dissolved in boiling HC1 gave by pre- 

 cipitation with H 2 S 0*7868 gram of HgS, eqnivalent to 

 0*67827 gram of metallic mercury. 

 Hence the salt contains 62*33 per cent, of Hg. 



(b.) 0*8232 gram of Hg salt, suspended in water and decomposed 

 by H 2 S, gave 0*5996 gram HgS, equivalent to 0*5169 gram 

 of mercury. 



Hence the salt contains 62*79 per cent, of Hg. 



The chlorine was determined (1) by decomposing the Hg salt under- 

 water with H 2 S and precipitating the filtrate with AgN0 3 ; (2) by 

 igniting the Hg salt with pure scdium carbonate, dissolving in water, 

 acidulating with HN0 3 , and precipitating with AgN0 3 . The follow- 

 ing results were obtained : — 



(a.) 0*8070 gram of the Hg salt gave 0*5226 gram of silver chloride, 

 equivalent to 0*1285 gram of chlorine, or 15*92 per cent, 

 of 01. 



