184. Mr. H. Croft's Abstract ofDv. H. Kopp's Researches 



Atomic volume of S = 53. 



Sulphuret of nickel 

 Iron pyrites 



NiS 

 FeS2 



97 

 150 



5-86 

 4-94 



5-76 

 4-90 



Atomic volume =: 78. 



Galena 



Copper glance 



Molybdenum glance , 

 Bisulphuret of tin ... 



Bismuth glance 



Antimony glance ... 



PbS 



Cu=S 

 MoS= 

 SnS* 

 Bi=S3 

 Sb- Ss 



7-76 

 5-74 

 4-44 

 4-42 

 6-40 

 463 



Atomic volume = 94. 



Sulphuret of copper... 



Manganese glance 



Sulphuret of zinc 



tip 



silver ... 

 Cinnabar 



Silver copper glance* 

 Variegated copper.... 

 Copper pyrites 



CuS 

 MnS 

 ZnS 



SnS 

 AgS 

 HgS 



Fe 

 C 



^e 1 

 :u^] 



S3 



Fe|g, 



Cu 



4-16 

 3-95 

 3-92 



4-85 



6-9 



8-0 



6-26 

 500 

 416 



In this table might also be placed some of the more complex 

 sulphurets, whose calculated specific gravities agree very well 

 with those observed. 



For the sulphurets of cadmium and platinum, it appears 

 necessary to adopt 110 as the atomic volume of sulphur. 



Arsenic is much more closely allied to the metalloids than 

 to the metals, and it seems that in its acids and sulphurets it 

 has the atomic volume = 119, and not its primitive one; in its 

 compounds with metals and their sulphurets, it seems to re- 

 quire the numbers 74. 



Jn water and in peroxide of hydrogen, the hydrogen seems 

 to possess the atomic volume 80, and oxygen 32, which it has 

 in most metallic oxides. 



Dr. Kopp then proceeds to a comparison of the relative 

 merits of the oxyacid and hydracid theories of the constitution 

 of salts, as far, at least, as regards their densities. To enter 

 fully into the reasonings adduced in favour of the hydracid 

 theory would lead us beyond the limits of this abstract : he 

 finds that if the oxyacid theory were retained, a greater num- 

 * Isometric copper glance. — Moks. 



