608 Intelligence and Miscellaneous Articles. 
easy style of exposition: The first chapter is devoted to a careful 
account of the construction of various forms of still, and contains 
many useful practical hints. The next few chapters deal with 
the boiling-point of a pure liquid, the vapour-pressures and 
boiling-points of mixed liquids, and the composition of the liquid 
and vapour phases (considered both experimentally and theoreti- 
eally). In chapter vii. we have detailed directions for carrying 
out a fractional distillation. The next two chapters deal with the 
theoretical relations between the weight and composition of the 
distillate, and the relation between the boiling-points of residue 
and distillate. Chapters x.—x1i. are devoted to a very full account 
of modifications of the still-head ; and in chapter xiii. the subject of 
continuous distillation is dealt with. Fractional distillation with 
an improved still-head is then taken up in chapter xiv., and distil- 
lation on the manufacturing scale in chapter xv. The important 
subject of fractional distillation as a method of quantitative 
analysis is next dealt with. In chapter xvii. we have an account 
of methods by which the composition of mixtures of constant 
boiling-point may be determined; and in chapter xviii. an account 
of the indirect method of separating the components of a mixture 
of constant boiling-point. The concluding chapter is devoted to 
general remarks on the subject. An Appendix containing tables of 
temperature corrections for the height of the barometer, and a 
very copious index form useful additions. A highly commendable 
feature of the.book consists in the numerous bibliographical refer- 
ences given at the end of each chapter. 
LXVII. Intelligence and Miscellaneous Articles. 
AN INSTRUMENT FOR DRAWING CONICS. 


To the Editors of the Philosophical Magazine. 
Trinity College, Dublin, 
GENTLEMEN, 14th April, 1904. 
\ ITH reference to my article in the March number of the 
: Philosophical Magazine, I wish to state that I have since 
received a paper in the Russian language by Prof. Prince 
Kougoushef of Warsaw, which was published in 1899, and is a 
description of a ‘new conicograph’ which is evidently the same 
as that which forms the subject of my paper. Although my 
instrument was constructed in 1895 and shown at the time to 
several scientific gentlemen connected with Trinity College, 
Dublin, I did not previously publish any account of it, and con- 
sequently Prince Kougoushef is fully entitled to claim priority. 
In making this acknowledgment I desire to express my regret 
that, at the time of writing my paper, I was unaware that it had 
been anticipated. | 
Iam, Gentlemen, 
Yours faithfully, 
J. R. Correr. 
