372 Transactions. — Chemistry and Physics. 



Note on Resin-oils. 



In a preliminary examination of the crude oil obtained 

 from the refuse, dust, and scrapings of the resin I noticed 

 that it absorbed I from a solution of I in KI when slightly 

 warmed. The method is to take a little of the oil, add starch 

 solution, shake them up, warm slightly, and then add deci- 

 normal I solution drop by drop, with vigorous shaking 

 between each drop, until the blue colour is permanent. 

 Neither linseed-oil nor turpentine will take away the colour 

 produced by even a single drop of decinormal I solution. 

 The sample of kauri-resin oil, however, gave a definite ab- 

 sorption. It seemed probable that all resin-oils would do 

 likewise, thus giving a method of detecting them in linseed- 

 oil or turpentine. I determined the absorption of the sample 

 of resin-oil, which was 1-708. I then made a mixture of 

 2-238 grams of linseed-oil and 0-1064 grams of resin-oil. The 

 calculated percentage of resin-oil in the mixture was there- 

 fore 4-5 per cent. I employed upon this mixture the method 

 given above. The decinormal I solution required to give a 

 permanent blue was 012 c.c. Therefore the percentage of 

 resin- oil in the mixture calculated from the experiment was 

 0-001524 x 100 x 100 _ ^.qq 



N 

 More accurate results could be obtained by using — - 



J ° 100 



1-7 X 2-3444 



More 

 I solution 



Investigation of Oils. 



First I distilled a small portion of the pure resin from a 

 glass flask with a thermometer inserted, in order to get the 

 proportions by weight of the various oils from a given weight 

 of resin : — 



(1.) First portion, 50°-100° ; about half of 



this was water ; light-vellow oil 

 (2.) 100°-190°; a darker-yellow oil 

 (3.) Dark yellowish-green ; 190°-280° 

 (4.) Above 280° ; darker still, fluorescent ... 

 (5.) Pitch left in distilling-flask ... 



Weight of resin taken 



Gas= ... ... ... 0-7542 4-4 



I have described before the class of resin used in my 



distillation. I distilled from a copper still with a copper 



