— 107 — 



a well-kept plantation the product is about 40 kilos of flowers per 

 1000 plants. 



Eucalyptus. The distillation of eucalyptus leaves is practically 

 not carried on at all, although, at any rate with Eucalyptus globulus, 

 from 90 to 120 fr. per year per hectare might be realised. 



Thyme. The oil is obtained from Thymus algetiensis, a familiar 

 plant in Tunis, which grows rather thickly in the districts of Zaghouan, 

 Pont-du-Fahs, Oudan, etc. The plant is distilled in a similar way to 

 geranium and yields 1,5% of oil. 



Mint. The oils are obtained by distillation of the leaves of penny- 

 royal and peppermint These two very hardy plants can easily be 

 cultivated in Tunis and reed little care. 1000 kilos of leaves produce 

 from 2 to 3 kilos of oil of a value of about 85 fr.(?) per kilo. 



Tuberose. The tubers of Polyanthes tuberosa, N. O. Liliaceae, are 

 planted in rows at a distance of 30 cm. 1000 plants produce from 

 25 to 30 kilos of flowers, which sell at 2 to 2,50 fr. per kilo. 



In 1907 Tunis imported 3423 kilos of essences and essential oils, 

 to the value of 33122 fr.; the exports amounted to 14862 kilos, 

 valued at 46127 fr. 



Bibliography. 



Otto Wallach, the well-known originator of modern terpene 

 chemistry, has published the result of his 25 years' pioneering invest- 

 igations in a comprehensive volume, entitled Terpene una 1 Campher. 

 Zusammenfassung eigener Untersuchungen auf dem Gebiet der alicyclischen 

 Kohlenstoffverbindungen^). (Terpenes and Camphors. Repertory of my 

 own Researches in the Domain of the Alicyclic Carbon combinations.) 

 This work is by no means a mere reprint of every single treatise 

 published by the author, who has written far more than a hundred 

 such, but contains the whole material scattered throughout these pub- 

 lications, arranged systematically in review from uniform points of view. 



In the general part of the work, Wallach first explains the prin- 

 ciples upon which he has proceeded in his investigations, after which 

 he deals with the mutual relations which he has found to exist between 

 the separate members of the terpene series. In addition to the 

 isomerisation processes, which are particularly characteristic of the series, 

 all the numerous conversions which have been observed are recorded, 

 arranged in tabular form as hydrocarbons, ketones, alcohols and oxides. 

 Then follows an exposition of the methods of research which have 

 been applied by Wallach with such extraordinarily prolific results. 

 This section is divided into chapters on addition reactions in saturated 

 and unsaturated combinations; reactions of interchange and abstraction; 



x ) Leipzig 1909, Veit & Co. 



