266 Kepurt on T>r Davidson s Papers. 



stated, the alcohol is not tinged when shaken with other oils, 

 such as seal oil, whale oil, &c., that one-tenth part of linseed 

 oil mixed with the others, gives to alcohol the yellowish tinge ; 

 so that we may consider the test as an indication of the pre- 

 sence of linseed oil, even though in small quantity ; but, though 

 under certain circumstances it acts as a test, we cannot put 

 confidence in it, for if the oil be previously mixed with a 

 little chloride of lime, as recommended by Dr Davidson in the 

 decolorizing of palm oil, though the colour is not destroyed, 

 yet the alcohol acquires no tinge from it. When oil thus 

 treated with chloride was mixed in the proportion of one-fourth 

 and of one-third with other oils, the mixture did not tinge the 

 alcohol, indeed the oil itself when shaken with alcohol did not 

 communicate colour to it. Though therefore, when an oil is 

 shaken with alcohol, and communicates to it a yellowish-green 

 tinge, we may conclude that it is adulterated ; yet Ave are by 

 no means warranted in concluding that there is no adultera- 

 tion when the alcohol is not tinged. 



Samples of oils, pure and adulterated with linseed oil, be- 

 fore and after admixture with chloride of lime are sent. 



A. Fyfe, Convener. 



Edinburgh, Wlh March 1839. 



List of Specimens re/erred to in the Report. 



Approved by Experimental Committee, adopted, and forwarded to Society. 

 20t/t March 1839. John Scott Russell, Pres. 



