6 Prof. W. N. Hartley and A. K. Huntington. 



original volume, it was found to possess exactly the same diactinic 

 quality as santal wood oil. (Diagram 6.) 



" Garraway Hydro carl) on. Boiling-point 350° F., specific gravity 

 0-8466,"* (Dr. Gladstone.) No. 2.— The portion boiling above 173° C. 

 was photographed. This substance, diluted to 1,000 and 5,000 times 

 its volume with alcohol, yielded the same results exactly as the former 

 sample and the oil of Indian geranium. (Diagram 6.) 



Oil of Birch Bark (Dr. Piesse). — The specimen was not re-distilled. 

 It showed a strong absorptive power until diluted to 4,000 times its 

 own volume ; from this point till an additional dilution of 8,000 volumes 

 had been reached its diactinicity rapidly increased. (Diagram 6.) 



MentJwle. Boiling-point 225° C. (Dr. Gladstone.) Prepared from 

 mint oil by means of the hydrosulphate. — After repeated distillations, 

 during which water separated from the first portions, the greater part 

 of the liquid boiled at 215° to 220°. This substance is remarkably 

 adiactinic ; even after diluting 20,000 times all rays from the line 18 Cd 

 onward were absorbed. (Diagram 6.) 



Oil of Juniper (Mr. Parries). — This was not re-distilled. When diluted 

 1,000 times, it transmitted very few of the rays beyond line Cd 12. 

 When diluted 10,000 times it transmitted the spectrum as far as Cd 24. 

 (Diagram 6.) 



Oil of Rosemary (obtained from Italy by Dr. Gladstone). — It boiled 

 between 180° and 200° C. When diluted 1,000 times it fails to trans- 

 mit the rays near line Cd 17, but there is a steady increase in trans- 

 parency on diluting 2,000, 4,000, and 10,000 times. (Diagram 6.) 



" Oil of Rosewood. Boiling-point 480° F., specific gravity=0'9042."* 

 ■ — (Dr, Gladstone.) This is one of the polymerised terpenes, C 15 H 24 . 

 It was found to boil at 250° C, yielding a pale yellow distillate. It 

 increased rapidly in transparency on dilution from 50 to 2,000 times, 

 after which stage up to 20,000 times the transparency did not greatly 

 increase. (Diagram 6.) 



Nutmeg Hydrocarbon.' — This is the specimen specially referred to in 

 Dr. Gladstone's paper. A few crystals resembling camphor were found 

 in the bottle. The liquid was poured off from these. The first distilled 

 fraction condensed in a turbid state and contained water. It boiled 

 between 159 u and 162 0, 5. The second fraction, equal to one-third 

 the whole quantity of liquid, boiled between 162 0, 5 and 164°. The 

 other three fractions boiled at temperatures ranging between 164° and 

 202°, and in addition to these portions there remained a solid residue. 



On dilution 1,000 and 5,000 times it proves to be amongst the most 

 diactinic of such substances. (Diagram 7.) 



Oil of Lavender (Mr. Farries).— It boiled between 170° and 180° C. 

 This oil was very soluble in aqueous alcohol, which at once shows it to 

 be perfectly free from turpentine. (Diagram 7.) 



* Quotation from original label. 



