410 ODOROGRAPHIA. 



essential oils \yith any degree of precision; all the English samples 

 possess an odour distinct from that of the foreign, a difference 

 whicli is readily noticed by the most casual observer; the sample 

 of foreign oil of rosemary is " softer," but also of far less " power " 

 and less suggestive of lavender. The sample No. 3 differs 

 somewhat from Xos. 1 and 2, having more the character of 

 No. 4. 



Specific gravity: — Xo. 1 0"911 



„ 2 0-924 



„ 3 0-901 



„ 4 0-8835 



The sp. gr. of foreign oil, as described by various observers, varies 

 from 0-881 to 0-907. 



Rotdtion. Only samples 1 and 4 were examined, the quantity 

 at disposal being insufficient in other cases : — 



Xo. 1 —9^35' 



„ 4 —33"* 



Soluhility in Spirit. The method adopted in applying this test 

 was the same as described in testing Santal wood oil (see above). 

 The temperature of the room was 16^-17^ C. The following 

 results were obtained, using 1 c. c. of oil and 2 c. c. absolute 

 alcohol : — 



Xo. of sample. C. c. diluted alcohol required. 



1 Infinite 



2 Infinite, slightly opalescent with 



8-5 c. c. 



3 2-65 c.c. 



4 0-8 c.c. 



Xo. 1, 3 pts. + Xo. 4, 1 pt.... 4-2 c. c. 

 Xo. 1, 2 xjts. + Xo. 4, 2 pts.... 2-2 c. c. 

 Xo. 1, 1 pt. + Xo. 4, 3 pts. .. 1-1 c.c. 



* The rotation of foreign oils of Rosemary varies greatly, but it is 

 considered that in a state of purity they should he dextrogyre. The tabulated 

 observations of various investigators omit to state whether the oils they 

 examined were distilled from the green or the dried plant, also whether the 

 woody stems were used or not, conditions which doubtless very much affect the 

 result. It is known that the plant is sometimes distilled in the fresh state 

 and sometimes in the dry — as in the island of Lesina, where it is dried for a 

 week or two in the sun. S. 



