118 Report of Schimmel § Co. April/October 1917. 



At the same time its intensity diminishes, so that possibly odourless compounds might 

 be formed if the methylation were pushed far enough. Huijer has ascertained concerning 

 the aniline series that the minimum, perceptibile diminishes for the higher links and that 

 the intensity of odour increases. The smell of the 3 isomeric toluidines varies; o-toluidine 

 has the least, ^-toluidine the strongest smell. When equimolecular solutions of these 

 are atomized the electrical charge shows a great increase in the case of the higher 

 links of the series, and of these 3 o-toluidine produces the smallest and i?-toluidine the 

 greatest charge. 



The maximum tension of the vapour of pure camphor. — Two methods are in use for 

 the determination of the maximum tension of vapours, viz., the barometric method and 

 the evaporation method. P. Datin 1 ) has compared both in relation to their reliability 

 by determining the maximum tension of the vapour of pure camphor. The barometrical 

 method gave the following results (in mm.): 0.46 (18.9°), 0.55 (23.4°), 0.94 (28.4°), 

 1.04 (30.8°), 1.32 (36°), 1.70 (40.2°), 2.22 (47°), 2.72 (52.5°), 3.12 (55°), 4.22 (62°), 5.61 (66:6°). 

 The evaporative method (passing a gas current slowly over a weighed quantity of sub- 

 stance and determination of the loss in weight) gave the following results: 0.39 (18.2°), 

 0.53(23.4°), 1.15(34.2°), 1.71 (40.3°), 2.24 (48.6°), 3.25 (57.8°), 8.66 (77.5°). Accordingly, 

 both methods lead to results which agree satisfactorily. The evaporative method is to 

 be preferred when it is a question of determining low pressures and in point of fact is 

 more suitable for maximum pressures which are lower than 2 mm.; however, it is only 

 really reliable when the air current is passed over for a considerable time. 



Botanical Notes. 



Sweet-smelling plants from German South-west Africa. — Some years ago we discussed 

 a paper by G. Volkens 2 ) on the valuable plants growing in Togo, in which the author 

 has also referred to a number of sweet-smelling ones. Those who care for further 

 information on the aromatic plants of our colonies will find the some particulars in a 

 publication by K. Dinter 3 ) on sweet-smelling plants from German South-west Africa. 

 Of course, the author only makes suggestions, and concerning many plants it will be 

 a doubtful matter if the aroma can be easily obtained and if it would be worth while. 

 Dinter believes that most of the plants. he discusses could be easily cultivated. 



He enumerates first of all the blossoms of some species of acacia, especially because 

 they might most easily be collected in quantities. In point of fact, all of the 28 species 

 which have hitherto been known to originate from this country have an odour, and none 

 of them an unpleasant one, but in no case do any of them even approach the violet- 

 like sweet odour of the camel-tree Acacia-Giraffce, whose delicious scent quite pervades 

 the air of the valleys which bear groundwater at the beginning of the dry and hot 

 early summer, i. e. in September. Acacia horrida has a similar, but not so purely violet- 

 like smell. The Ana-tree, Acacia albitfa, blossoms towards the end of May, already in the 

 cold season, and its odour reminds most of limeblossom. The same applies to Acacia 

 hebeclada which blossoms in September. 



The blossoms of the Thymelacea, Gnidia polycephala. which flower in midwinter in 

 Okahandja possess a wonderfully sweet smell like orange flowers. 



x ) Annul, de Phys. IX. 5 (1917), 218; Chem. Zentralbl. 1916, II. 1915. — 2 ) Notizblatt des Kgl. Bot. Gartens 

 und Museums zu Berlin-Bahlem, Appendix XXII. 3, (Nov. 30 th 1910), 70; Report April 1911, 144. — 3 ) Deutsche 

 Parf.-Ztg. 3 (1917), 53. 



