— 158 — 



jn the essential oil industry, but also to that wider circle which is 

 theoretically or practically interested in the evaporation of solutions or 

 mixtures of fluids of any kind. The entirely different scope of the work, 

 as compared with the brief chapter dealing with a much narrower field 

 which appeared some years ago, ought alone to constitute sufficient 

 justification for its appearance as a separate book. The separate 

 sections deal with the following subjects: — The practice of distilling; — 

 Dalton's law of Diffusion ; — Distillation of mixtures of mutually insoluble 

 liquids; — Distillation under increased and diminished pressure ; — Distillation 

 by superheating ; — Chemico-physical processes in the distillation of 

 plants; — Distilling on a small scale and itinerant stills; — Molecular 

 association and dissociation: its influence upon evaporation; — Distilling 

 temperatures and steam-pressure of uniform bodies; — General information 

 on solutions; — Distillation of mixtures of liquids which are mutually 

 soluble in a certain degree; — Distillation of homogeneous mixtures with 

 minor boiling temperature; — Distillation of labile additive compounds; — 

 Homogeneous mixtures with major boiling temperature. 



The well-known work on the Volatile Oils edited under our auspices 

 by E. Gildemeister and F. Hoffmann, and published about 11 years ago, 

 has for some time been out of print. A second edition was therefore 

 urgently called for, and we are pleased to be able to report that the first 

 volume thereof, edited by E. Gildemeister under collaboration of several 

 chemists engaged in our laboratories, has now made its appearance 1 ). 

 Owing to the enormous increase of subject-matter, which could no longer 

 conveniently be brought together into a single volume, a two-volume 

 edition has become necessary. The new edition is distinguished from 

 its predecessor in that the history of each essential oil is immediately 

 joined to the account of the preparation of the same oil, thus making it 

 possible to complete the historical part. A chapter on the preparation 

 of the odoriferous principles of plants by the extraction-process has been 

 added, and the principal synthetic odoriferous substances, which were not 

 dealt with in the first edition, are passed under review. In view of the 

 appearance of v. Rechenberg's book, however, the references to the theory 

 of steam-distilling have been omitted. The tables for calculating the ester- 

 and alcohol-contents of essential oils from the saponification numbers 

 obtained before and after acetylation have been extended, and a new table 

 has been added from which the corresponding ester-numbers and other 

 values connected therewith may be directly read-off from the number of 

 cubic centimetres of semi-normal alkali-solution used for 1 ,50 g. of oil. Loose 



*) Die atherischen die (The Volatile Oils), by E. Gildemeister and F. Hoffmann. Second 

 (German) edition by E. Gildemeister, edited under commission from the firm of Schimmel £j Co., 

 Miltitz near Leipzig. Vol. I. Published by Schimmel fy Co., Miltitz near Leipzig 1910, and sold 

 to the book-trade by L. Staackmann, Leipzig. 



