90 Dr. Apjohn on the Potatoe Spirit Oil 



as peculiar to potatoe spirit, occurs also in that which is de- 

 veloped during the fermentation of grain. From this latter 

 source it admits of being procured in great quantity. When 

 first observed by Mr. Coffey at Sir Felix Booth's, there was 

 an inch of it in the faint receiver, and from the diameter of 

 the vessel he estimated its total amount at 50 gallons. This 

 is the quantity produced at that establishment every fortnight, 

 the excise laws compelling the distiller to distil and brew 

 alternately, and a week being generally consumed in each 

 process. 



The whisky manufactured some years ago contained a 

 considerable quantity of this oil, and owed to its presence a 

 great deal of the pungency of taste by which it was distin- 

 guished. 



From its high boiling point, and the nature of the stills at 

 present used, but a very small portion of this substance now 

 passes over, and hence the reason why the spirit at present 

 made is, as compared with the product of the old processes, 

 less disagreeable to the palate, and probably less injurious to 

 the constitution. It is no doubt owing to the same cause, viz. 

 an improvement in the process of distillation, that this oil has 

 at length been noticed in the distillers' faints. Upon the old 

 system of manufacture the greater portion of it was driven 

 over, and was held dissolved by the spirit into which it was 

 thus introduced ; but with the modern stills, particularly that 

 devised by Mr. Coffey, nothing having so high a boiling 

 point as this oil can by possibility pass into the part of the 

 apparatus where the spirit is condensed. With respect to 

 the manner in which the substance originates, whether it ex- 

 ists ready-formed in the materials subjected to fermentation, 

 or is a product of the process, I am not aware of any facts 

 calculated to decide such a question. As, however, it is found 

 in the fermented wash of both corn and potatoes, it may be 

 presumed to be derived from the starchy principle, which is 

 common to both. 



The potatoe spirit oil, as it has hitherto been called, has I 

 find of late attracted much attention. Pelletier from some 

 rough experiments upon it with acids, threw out the con- 

 jecture that it was more analogous to alcohol than to the true 

 volatile oils, and this opinion would seem to have been in some 

 degree adopted by Dumas. More recently {Ann, de Chimic 

 et de Phys., Jan., 1839) M. Auguste Cahours has revived this 

 opinion, and concluded it to be one of the group including 

 alcohol, pyroxylic spirit, and acetone, and has even succeeded 

 in procuring from it a carbo-hydrogen, in which the elements 

 are, as usual, associated in the ratio of atom and atom. M. 



