obtained in the Decomposition of Oil. 187 



statement is but little different from the following theoretical 

 one, deduced partly from the former experiments : — 1 volume 

 of vapour requires 7*5 volumes of oxygen for its combustion; 

 6 of the latter combine with carbon to form 6 of carbonic 

 acid, and the 1*5 remaining combine with hydrogen to form 

 water. The hydrogen present therefore in this compound is 

 equivalent to 3 volumes, though condensed into one volume 

 in union with the carbon ; and of the latter elements there are 

 present six proportionals, or 36 by weight. A volume there- 

 fore of the substance in vapour contains 



Carbon 6x6 =36 



Hydrogen 1x3=3 



39 

 and its weight or specific gravity will be 39, hydrogen being 1. 

 Other experiments of the same kind gave results according 

 with these. 



Among the liquid products obtained from the original fluid 

 was one which, procured as before mentioned, by submitting 

 to 0° the portion distilling over at 180° or 190°, corresponded 

 with the substance already described, as to boiling points, but 

 differed from it in remaining fluid at low temperatures ; and 

 I was desirous of comparing the two together. I had no 

 means of separating this body from the bi-carburet of hydro- 

 gen, of which it wovdd of course be a saturated solution at 0°. 

 Its boiling point was very constantly 186°. In its general 

 characters of solubility, combustibility, action of potassium, &c., 

 it agreed with the substance already described. Its specific 

 gravity was 0*86 at 60°. When raised in vapour 1*11 grain 

 of it gave 1*573 cubic inch of vapour at 212°, equal to 1*212 

 cubic inch at 60°. Hence 100 cubic inches would weigh 

 about 91*6 grains, and its specific gravity would be 43*25 

 nearly. In another experiment, 1*72 grain gave 2*4 cubic 

 inches at 212°, equal to 1*849 cubic inch at 60°; from which 

 the weight of 100 cubic inches would be deduced as 93 grains ; 

 and its specific gravity to hydrogen as 44 to 1. Hence pro- 

 bably the reason why, experimentally, the specific gi'avity of 

 bi-carburet of hydrogen in vapour was found higher, than by 

 theory it would appear to be when pure. 



Sulphuric acid acted much more powerfully upon this sub- 

 stance than upon the bi-carburet: great heat was evolved, 

 much discolouration occasioned, and a separation took place 

 into a thick black acid, and a yellow lighter liquid, resisting 

 any further action at common temperatures. 



0*64 grain of this substance was passed over heated oxide 

 of copper: 4*51 cubic inches of carbonic acid gas were ob- 



A a 2 tained, 



