BETWEEN THE VISCOSITY OF LIQUIDS AND THEIR, CHExMICAL NATURE. 87 
Standards Committee, in the laboratory of the Royal College of Science, by 
Mr. Alfred Greeves. 
The English fasel oil was obtained from potato spirit, the Scotch from spirit 
prepared from a mixture of maize and barley, and the Irish from spirit made from 
barley alone. In each case the fusel oil was fractionated, and the portion boiling’ 
between 128° and 132° was used in the preparation of the isopentane. 
The alcohol was converted into the iodide, which was washed with a solution of 
soda, then with water, and after drying over calcium chloride was carefully 
fractionated. 
The iodide was reduced by means of a copper-zinc couple, and the mixture of 
isopentane and amylene thus produced was placed over excess of bromine for two 
days. The product was then separated from the bromine, washed with an ice-cold 
solution of soda, and then submitted to fractionation, which - affords a ready method 
of separating the isopentane from amylene dibromide. As a further precaution 
against the presence of traces of amylene, amylene dibromide, or amyl iodide, the 
product was treated with fuming sulphuric acid for some hours. As this acid 
attacks isopentane to some extent, on removal from the acid the product was washed 
with dilute soda and then with water to remove sulphur dioxide; it was next dried 
over ordinary sulphuric acid for some days, then over sodium wire, and finally 
submitted to fractionation. 
The observed boiling-points were :— 
I. From English amyl alcohol . . 28°’17 to 28°'27. Bar., 7G5’9 millims. 
IT „ Scotch „ „ . . 28°T0 to 28°-]2. „ 7G2-5 
III. „ Irish „ „ . . 27°-G5 to 27°-70. ., 750-3 
Corrected and reduced boiling-points :— 
I. TI. III. 
27°-99 28°-04 28°-04 
These values are considerably lower than most of the published determinations of the 
boiling-point of isopentane. They are almost identical, however, with that recently 
found by Young, and by Young and Thomas, viz., 27”-95 (‘Proc. Phys. Soc.,’ vol. 13, 
pp. 607 and 666 , 1895). 
Determinations of vapour density :— 
I. IL III. 
Found 36-05 35‘78 35-55 
35*61 35-62 35*63 
The following are the observations for viscosity :— 
Calculated; 35*83. 
