172 On some new Products [1825. 



In the same way some of the more fixed essential oils may 

 be used, as dry oil of turpentine ; and even a portion of the 

 condensed liquor itself, as that part which requires a tempera- 

 ture of 220 or 230 for its ebullition; care being taken to 

 estimate the expansion of the gas by the vapour of the liquid, 

 which may readily be done by a known portion of common air 

 preserved over the liquid as a standard. 



With reference to the proportions of the different substances 

 in the liquid as obtained by condensation of oil-gas, it is 

 extremely difficult to obtain anything like precise results, in 

 consequence of the immense number of rectifications required 

 to separate the more volatile from the less volatile portions ; 

 but the following Table will furnish an approximation. It con- 

 tains the loss of 100 parts by weight of the original fluid 

 by evaporation in a flask, for every 10 in elevation of tempera- 

 ture, the substance being retained in a state of ebullition. 



100 parts at 58 parts. differences. 



had lost at 70 ... 1-1 - q 



80 ... 3-0 gl 



90 ... 5-3 . 



100 ... 7-7 " 



no ... 10-1 f 7 



120 ... 13-2 * * 



130 ... 16-1 ** 



140 .., 19-3 



150 ... 22-4' *. 



160 . . 25-6 o. 4 



170 ... 29-0 1*7 



180 ... 44-7 il' 



190 ... 68-1 



200 ... 84-2 7: 



210 , . . 91-6 S7 



220 . . . 95-3 ?' 



230 ... 96-6 



The residue, 3'4 parts, was dissipated before 250 with slight 

 decomposition. The third column expresses the quantity vola- 

 tilized between each 10, and indicates the existence of what 

 has been described as bicarburet of hydrogen in considerable 

 quantity. 



