102 Mr. Faraday oil new Compounds [Feb. 



absorbed in a given time was much diminished ; and in those 

 cases it was hardly appreciable in two hours ; a length of time 

 which appears to be quite sufficient for the removal of any of the 

 peculiar vapours from oil or coal gas. 



My mode of operating was generally in glass tubes over clean 

 mercury,* introducing the gas, vapour or mixture, and then 

 throwing up the sulphuric acid by means of a bent tube 

 with a bulb blown in it, passing the acid through the mercury 

 by the force of the mouth. The following results are given as 

 illustrations of the process : — 



Oil gas from a gasometer. 



in 8' in 1 hour. 2 hours, diminution. 



188 vol. + 9'5 vol. sulphuric acid diminished to 155* 148-5 146*4 22*12 per cent. 



107 +13- 88-5 84-5 82-0 23"33 



138 + 5-2 113-7 1080 1065 22-82 



Oil gas from Gordon's lamp. 



15' 30' 3 hours. 



214 + 6-8 ...... 1833 1808 176- 17-75 



159 +5-9 137-5 136-0 130-4 17-98 



113 +12-2 98-0 96-0 920 18-68 



Coal gas of poor quality. 



54Sfi +27-6 533-3 529-2 529- 3-57 



273-6 +27-8 267-9 266- 266- 2-78 



J906 +13-1 186- 184-2 184-1 3-41 



Oil may also be used in a similar manner for the separation 

 of these vapours. It condenses about six volumes of the most 

 elastic vapour at common temperatures, and it dissolves with 

 greater facility the vapour of those liquids requiring higher tem- 

 peratures for their ebulUtion. I found that in mixtures made 

 with air or oxygen for detonation, I could readily separate the 

 vapour by means of olive oil ; and when olefiant and other gases 

 were present, its solvent power over them was prevented, by 

 first agitating the oil with olefiant gas or with a portion of the 

 gas to saturate it, and then using it for the removal of the vapours. 



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

 used, as (hy oil of turpentine ; and even a portion of the con- 

 densed liquor itself, as that part which requires a temperature 

 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 any thing like precise results, in 



• If the mercury contain oxidizable metals, the sulphuric acid acts upon it, and 

 evolves sulphurous acid gas. It may be cleaned sufficiently by being left in contact 

 with sulphuric acid for 24 hours, agitating it frequently at intervals. 



