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chemist, viz., capillarity as a property on which a method 
of analysis may be based. Capillary constants of liquids, 
and their relation to chemical composition and constitution, 
have been recently carefully studied by Schiff, who deter- 
mined these constants at the boiling temperatures of the 
liquids. More recently, Traube has investigated the con- 
stants of substances in solution, a practical outcome of which 
has been a method for determining the percentage of fusel 
oil in spirits and wines. This method is fully given in the 
Berlin Berichte, XIX., 892, and the apparatus described in 
the Journ. f. Prakt. Ch. (2) XXXI., 177. Wishing to extend 
this method, and simplify it, if possible, for practical pur- 
poses of rapid analysis, I undertook the determination of 
the capillary constants of benzene, and those homologues of 
benzene which occur in coal-tar. The reason for attacking 
this special line was simply because, as those who are 
acquainted with the coal-tar industry know, the methods at 
present in use for determining the percentage constituents 
of benzene and its homologues occurring in commercial 
coal-tar naphtha, are rough methods, and lack accuracy; 
and there is, especially, no quick method for determining 
the presence and estimating quantitatively carbon-bisul- 
phide, paraffin, or petroleum, which are often found in the 
commercial products. In these determinations I must 
admit, at the outset, that no very great success has attended 
them ; at the same time, the value of the method should 
not be overlooked ; and, as to the results, I have very little 
doubt that those who care to pursue the subject will hit 
upon something which will turn out more useful and suc- 
cessful — for example, in the analysis of mixtures of oils. To 
fulfil the conditions of a practical analytical method, the 
apparatus must be of simple construction, easily manipulated, 
and the determination rapidly performed, consistent, of 
course, with accuracy. For comparative determinations. 
