352 Dr. Ure on the Ultimate Analysis of [May, 



terms, we shall have 1 atom cyanogen, 6 atoms olefiant gas, 

 2 atoms carbonic oxide, and 6 atoms of carbon in excess." 



"I had intended to pursue, at considerable detail, my researches 

 on this curious azotized product of vegetation, but the subject 

 having been lately taken up, and ingeniously prosecuted by my 

 pupil and friend, Mr. Walter Crura, I was induced to leave it in 

 his hands. He announced to me the presence of hydrogen in 

 indigo, before I had analyzed this substance myself; and drew 

 ray attention particularly to the fallacy occasioned by the hygro- 

 metric water of the peroxide of copper. It is likely that some 

 slight modification may require to be made in my tabular propor- 

 tion of the constituents, for I did not resume the subject of 

 indigo, after I had become most familiar with the manipu- 

 lations." 



" Camphor is very nearly represented by carbon, 10 atoms ; 

 hydrogen, 9 ; oxygen, 1 ; or 9 atoms olefiant gas + 1 atom car- 

 bonic oxide. Napthaline is, in my opinion, a solid bicarburet of 

 hydrogen, consisting of carbon, 2 atoms; hydrogen, 1." 



" Itfis very difficult, even by the best regulated ignition, to 

 resolve the whole carbon of this very volatile body into carbonic 

 acid ; hence, the carbon may come to be underrated in the 

 result." Naphthaline is obtained during the rectification of the 

 petroleum of the coal gas works. It is found encrusting the pipes 

 in the form of a greyish crystalline mass ; and when purified by 

 a second sublimation at the temperature of about 220°, it forms 

 beautiful thin plates, white and glistening. It has a powerful 

 petroleum odour. With brine of the specific gravity 1-048, these 

 plates, when once thoroughly wetted (which is difficult to effect), 

 remain in equilibrium ; that is, float in any part of the liquid. 

 That number, therefore, represents the specific gravity of naph- 

 thaline. It is insoluble in water, but very soluble in ether, and 

 moderately so in alcohol. With iodine, it fuses at a gentle heat 

 into a brown liquid, forming as it cools a solid resembling plum- 

 bago, which dissolves readily in alcohol, and is thrown down by 

 water. Naphthaline is soluble in oils. In water heated to 168° 

 Fahr. it fuses, and remains like oil at the bottom of the liquid ; 

 bat when stirred, it rises, and spreads on the top in little oily 

 patches. At 180° it rises spontaneously from the bottom in oily 

 globules, which, as the temperature is raised, dissipate in the air, 

 undergoing motions similar to those of camphor floating on 

 water. 



" Spermaceti oil is constituted apparently of carbon, 10 atoms; 

 hydrogen, 9 ; oxygen, 1 ; or, in other words, of 9 atoms olefiant 

 gas + 1 atom carbonic oxide. The experimental proportion is, 

 however, more nearly carbon, 10 atoms; hydrogen, 8; oxygen, 1. 

 There is here an atom of carbon in excess."* 



" " This is probably the truer view. The former would make it coincide with cam. 

 phor." 



