Essential Oil of Sage. 339 



lation was very probably produced, or at any rate partly pro- 

 duced, by the polymerizing action of heat upon the original 

 constituents of the oil. 



4. That portion of the distillate \yhich boiled from 156° to 

 158° was fractionated until the greater portion boiled con- 

 stantly at 157° to 157°*5 (thermometer surrounded with 

 vapour, and barometer at 760 millims.). The liquid so ob- 

 tained was perfectly colourless ; it had an exceedingly slight 

 odour of sage. 



We have not subjected this liquid to analysis; but the 

 results of a determination of its vapour-density, and a con- 

 sideration of its genera] properties, leave no doubt that it 

 really consists of a terpene, Cio Hi^. 



The vapour-density was determined by a slight modification 

 of Hofmann's method, which we have described in a paper 

 communicated to the Chemical Society*. The method is easily 

 and quickly carried out, and yields results sufficiently accurate 

 for general purposes. 



The followino' numbers were obtained : — 



o 



Height of barometer =755 millims. 



Temperature of air =17°. 



Height of mercury column in barometer tube =561 

 millims. 



Temperature of vapour =185°. 



Tension of mercury vapour at 185° =12 millims. 



Weight of mercury required to occupy space formerly 

 occupied by vapour =1018*4 grms. 



Temperature of mercury = 20°. 



Hence, volume of vapour =73*28 cubic centims. 



Weight of liquid =0-0682 grm. 



Weight of volume of hydrogen equal to volume of vapour 

 under same conditions of temperature and pressure =0'00101 

 grm. 



Hence M=:.^2 =67*46. Calculated = 68. 



5. The specific gravity of this terpene was 0*8635 at 15°. 

 To Dr. Grladstone we are indebted for determinations of 



the refractive indices of this terpene. We desire to give our 

 best thanks to him for his great kindness. 



M=l*4611. yu,D=l*4667. /xH = l*4855 at 24°*5. 



Hence specific refractive energy = 0*0534, and 

 Refraction-equivalent = 72*6. 



6. Dr. Tilden has been so very good as to examine the 



* Chem. Soc. Journ. vol. ii. 1877, p. 140, 

 Z2 



