68 REPORT—1840. 
phite, the author extended the principle here argued to certain other 
substances, considered generally as simple bodies. For example, sul- 
phur obtained by the decomposition of sulphurets by acids, is white in 
colour, and invariably combined with a stable quantity of hydrogen ; 
but obtained from hyposulphites, it is as invariably yellow, and the 
presence of free hydrogen in the slightest quantity bleaches the pre- 
cipitate. The known case of sulphur precipitated under the presence 
of sulphuretted hydrogen, and cautiously mixed with metallic copper 
in its utmost state of minute division, being found to combine directly, 
evolving a dull red heat, has been considered an exception to the law, 
that no two dry bodies unite without the intervention of a third; but 
sulphur precipitated from hyposulphites, will not thus combine, nor will 
pure sulphur, though subjected to the minutest division possible. The 
same sulphur, however, brought into contact with hydrogen, under a 
pressure of four atmospheres, and then quickly mixed, is found to com- 
bine, as in the first instance; but if exposed to the air, its power of 
combination is again lost; thus a third body is proved necessary here, 
as in all cases. And further, the author doubted if one of the two 
different crystalline forms of sulphur is not owing to the presence of 
hydrogen, which he found to be in combination with it in a very per- 
ceptible quantity. These peculiar forms of combination, where a few 
atoms of one body are combined with a high number of atoms of an- 
other, may be considered, perhaps, as forming a class of compounds 
intermediate between the inorganic and the higher organic compounds : 
thus the compounds of arsenic acid form a very striking example. In 
the subarseniate of iron, 50 atoms of iron are combined with only 3 
atoms of arsenic acid and 75 of hydrogen. So again, 24 atoms of 
arsenic with 1 atom of sulphuret of potash in sulph-arseniate of 
potash. By gradually passing from compounds of inorganic chemistry 
to those of organic chemistry, we find di-acetate of copper with water, 
48 atoms of oxide of copper combined with only 1 atom of hydrogen 
and 12 atoms of water. And finally, in the field of organic chemistry 
itself, we have, for example, margaric acid, composed of 67 atoms of 
hydrogen, 35 carbon, and 3 of oxygen only. In the oleic acid, 120 
atoms of hydrogen are combined with 70 of carbon and 5 of oxygen; 
in the stearic acid, 134 atoms of hydrogen with 70 of carbon and 5 of 
oxygen, &c. The author hinted in his paper in the Philosophical Maga- 
zine, thatthe principal circumstance which tended to produce compounds 
of such multiplicity of atoms, or, in fact, organic compounds, was the se- 
paration of the molecules of bodies brought into action by the capillary 
powers of the vessels of organic structures. It was probable that the che- 
mical action of these separated molecules must be a different one from 
their action, when arranged into one definite form; and as proof that 
once-received laws of affinity were exhibited only under peculiar cireum- 
stances, he directed the attention of the Section to H. Rose’s compound, 
formed by direct combination of 29°97 per cent. of ammonia with 70°03 
per cent. of sulphuric acid, which ought to have produced anhydrous sul- 
phate of ammonia; but after combination, neither sulphuric acid nor 
ammonia could be detected in the compound. The same chemist found 
