— 34 — 



especially in regard to their essential oils" 1 ) H. G. Smith 2 ) gives 

 the indices of refraction and a few other properties of 1 1 8 authentic 

 eucalyptus oils, which with few exceptions had been distilled at the 

 Technological Museum of Sydney from leaves of which the botanical 

 origin had been determined by Baker. Smith determined the re- 

 fractive indices, specific gravities, and solubilities of the oils in 70 per 

 cent. (di5,5o 0,8722) alcohol at 16 , and calculates, apart from the 

 specific refractive power, for the oils rich in eucalyptol, numbers which 

 appear to him useful for valuing the quality of the oils, by multi- 

 plying the value of the refractive index with ten times the value of 

 the vol. 70 per cent, alcohol required for dissolving 1 vol. oil. The oils 

 richest in eucalyptol make the best solutions with 70 per cent, alcohol, 

 and have the smallest index of refraction, so that they stand at the 

 top of the series arranged by Smith; it is clear from the numbers 

 given, that the simple determination of the solubility by itself is at 

 least of equal value, if not more valuable, than this new and more 

 complicated method. Smith arranges his results in tables corresponding 

 to the compositions of the oils. 



The first group consists of oils rich in eucalyptol containing pinene, 

 and usually free from phellandrene, whose refractive index was chiefly 

 found above 1,47 -and below 1,48. To these belong: 



E. amygdalina, E. Behriana, E. bicolor, E. Bosistoana, E. Bridgesiana, 

 E. Cambagei, E. camphora, E. cznerea, E. cneorifolia, E. cornea , E. cordata, 

 E. dealbata, E. dumosa, E. eugenioides, E. Globulus, E. goniocalyx, E. gra- 

 cilis, E. hemilampra, E. intertexta, E. longifolia, E. maculosa, E. Maideni, 

 E. melliodora, E. microcorys, E. Morrisi, E. occidentalis, E. odor a fa, E. oleosa, 

 E. ovalifolia v. lanceolata, E. paludosa, E. pendula, E. polyanthema, 

 E. polybractea, E. populifolia, E. propinqua, E. pulverulenta, E. punctata, 

 E. quadrangulata, E. redunca, E. resinifera, E. Risdoni, E. Rossii, E. rostrata 

 var. borealis, E. salmonophloia , E. Seeana, E. sideroxylon , E. Smithii, 

 E. squamosa, E. stricta, E. Stuartiana, E. viminalis var. 



In the second group are found oils free from phellandrene, con- 

 taining pinene, whose refractive index lies above 1,47 and below 1,48. 

 These are the oils of E. botryoides, E. calophylla, E. dextropinea, E. diver- 

 sicolor, E. laevopinea, E. saligna, E. Wilkinsoniana. 



To the oils of the third group, free from phellandrene, containing 

 pinene and sesquiterpene ( n Di6o above 1,48) belong the oils of E. affinis, 

 E. apiculata, E. Baeuerleni, E. corymbosa, E. eximia, E. intermedia, 

 E. lactea, E. maculata, E. nova-anglica, E. paniculata, E. patentinervis, 

 E. rubida, E. tesselaris, E. trachyphloia. 



1 ) Sydney 1902. Comp. Report April 1903, 40. 



2 ) According to reprint kindly sent to us. Journ. and Proceed, of the Royal 

 Soc. of N. S. Wales 39 (1905). 



