§142. COLOUB-BEACTIONS. 



121 



per cent. These figures are true for fresh oils only, and for tem- 

 peratures ranging from 20° to 22°.i 



I found the following proportions of weaker alcohol necessary 

 to form clear mixtures with the foregoing oils : 



§ 142. Colour-reactions.— I have observed the following colour- 

 reactions with certain ethereal oils :" 



Solution of bromine in chlorofoo-m (1 in 20), in the proportion of. 

 10 to 15 drops to one of oU, gives colourless mixtures with oils of 

 turpentine, caraway, lemon, coriander and cardamoms ; yellow 

 with bergamot, bitter orange and neroli ; slowly turning green with 

 cloves, ginger, lavender, cajeput, cascarilla ; slowly turning greenish- 

 blue with ol. menth. crisp., oils of juniper, pepper and galangal ; 

 greenisMrown or hroum with sweet marjoram, dill, cummin and 

 valerian; a more or less fine rose, red, or reddish-violet tint is 

 gradually produced by rosemary, fennel, anise, star-anise, cinna- 

 mon, nutmeg, thyme, peppermint, mjn-rh and parsley ; brownish- 

 violet with mace; blue, or bluish-violet with cubebs, copaiba, 

 amomum, laurel, sandal-wood and sweet flag ; orange with oil of 

 worm-seed, oil of cedar-wood ; and with camphor. 



' N. Eepert. f. Pharm. xxii. 1, 1872; Pharm. .Tuuru. and Trans. [3], vi. 

 ,541 et sell. ^^^ ^^^ Gfodetfroy nnd Ledermaim, Zeilschr. d. allgem. oesterr. 

 Apotheker "Ver. xv. 381 et seq. ; Jahresb. (. Ph-avui. 3y4, 1877. 



" Pharm. .Tourn. and Trans. [3], vi. 681 ; Archiv d. Pharm. [3], xii. 289. 

 See also Hager, Pharm. Centralblalt, 137, 169, 195, 1870; and yiiiokiger, 

 Sehw«iz. Wochenschr. f. Pharm. 261, 1870. 



