( 264 ) 



Feport of the Experimental Committee of the Society of Arts 

 for Scotland, on Dr Davidson^ s proposed methods of Decolo- 

 rizing Palm Oil, Bemoving the Bitter Taste and Lichenous 

 Odour of Iceland Moss, and the Fetid Odour of Fish Oils, 

 and for detecting the Adulteration of Fixed Oils* Com- 

 municated by the Society of Arts of Scotland. 



-• I. — Decolorizing Palm Oil. (555.) 



f The method proposed by Dr Davidson was tried with a 

 palm oil, very dark in its colour, and succeeded completely in 

 bleachinf? it to that degree that it may be used in the manu- 

 facture of white soap. 



A specimen of the oil before and after being bleached is sent. 



I can conceive only one objection to the successful practi- 

 cal application of this method. The chloride of lime, when 

 first applied, decolorizes to a certain extent ; and the bleach- 

 uig seems to be afterwards completed by exposure to light ; 

 hence the absolute necessity of breaking the congealed oil to 

 pieces, and frequently stirring it, so as to expose fresh sur- 

 faces to the light. When this is not done, the decolorizing 

 process goes on slowly. With a little oil, the bleaching may 

 be effected in a day or two, — of com-se the time depends on 

 the state of the weather : with sunshine, it goes on rapidly. 

 AVhen the quantity is very large, I suspect it will take a much 

 longer time to complete it than Dr Davidson mentions ; but 

 this is mere conjecture. The quantity on which I operated 

 did not exceed a quarter of a pound, which required nearly a 

 fortnight, with very frequent stirring. The weather, how- 

 ever, with the exception of the three last days, was unfavour- 

 able, there being little sunshine. 



If this objection does not apply when the process is conducted 

 on a large scale, I consider the method proposed well adapted 

 for accomplishing the object in view. 



n. On the Removal of the Bitter Taste and Lichenous Odour of 



Iceland Moss, ^r. (557) 

 Two processes are recommended by Dr Davidson : one by 



the use of solution of potassa ; the other by lime. Both of 



" ':j_ 1 — - i4- 



9B ttiiiJ iiiiti .'i'ti*' Read and approved 10th April 1839. ^,(j ,fji^ 



( 



