Fractional Distillation of Kerosene. 495 



is 51 x 10 6 , and even than any of the woods as given in 

 volume iii. of Lord Kelvin's ' Collected Papers.' On account 

 of the thread not being circular, -the calculation of the Rigidity 

 Modulus would of course be valueless. 



A rough trial was made of the Torsional Rigidity ; but as 

 the thread was very much finer than that used by Professor 

 Tanakadate, being about one third the diameter, it was diffi- 

 cult to obtain a light enough twisting-weight. The result 



I'll OO mi 



obtained, however, agreed with that given by Prof. Tanaka- 

 date, in so far as it showed that the torsional rigidity of 

 spiders' thread is considerably less than that of silk fibre. 



XLIX. The Method of Fractional Distillation illustrated by 

 the Investigation of Kerosene. By J. Alfred Wanklyn 

 and W. J. Cooper *. 



A LIQUID known as kerosene, or Russian kerosene, is 

 imported into this country in immense quantities. 

 The liquid is produced by the distillation of crude natural 

 Russian petroleum in Baku, and is conveyed in tank-ships to 

 London. It arrives in this country in the condition of an 

 almost colourless oil, with very little smell, and of sp. gr. 

 0*825 at 15 0, 5 C. Apparently it is very constant in quality 

 and composition. 



The knowledge of it which we owe to former investigators 

 is that it is a mixture of hydrocarbons of the general formula 

 C„H 2 ?i ; that these hydrocarbons are not olefines, but are 

 isomers of the olefines, being not readily attacked by reagents. 

 Very few of the members of the series have been described by 

 former investigators. We have made a study of kerosene as 

 follows : — 



When kerosene is rapidly distilled in a glass retort, 70 per 

 cent, comes over below 250° C, about 20 per cent, between 

 250° and 300°, and the residual 10 per cent, may be almost 

 completely volatilized ; the last 5 per cent, requiring, how- 

 ever, a temperature much above the boiling-point of mercury. 



By careful quantitative experiment, a carefully measured 

 litre of kerosene being distilled in two operations, half a litre 

 at a time, it was ascertained that there is neither expansion nor 

 contraction during distillation. The observation was also made 

 that not until the temperature had risen to 170° C. did the 

 first drop of liquid distil over. 



* Communicated by the Authors. 



