258 Dr Davidson on the Removal of the 



into the atmosphere. There is also considerable economy in 

 combining the Avhole of the chloride of Imie with the oil in the 

 form of a cream, in place of making a clear solution of it ; for, 

 by the latter method, a considerable portion of the liquor does 

 not unite thoroughly with the oil, and, consequently, the whole 

 of its decolorizing power is not made available. Much more 

 acid, however, is required, when the whole of the chloride of 

 lime is combined with the oil, than when the clear solution is 

 employed ; but, as sulphuric acid is much cheaper than chloride 

 of lime, an additional portion of it will be less expensive than an 

 additional portion of the other. This process, with the largest 

 quantity of chloride of lime stated, will render palm oil as 

 white as ordinai-y commercial tallow, provided the oil and chlo- 

 ride have been intimately combined, and provided the mass 

 has been exposed to the air and light for a week or two ; and 

 may be employed in the manufacture of white soap ; but, where 

 it is intended for yellow soap, the bleaching does not require 

 to be so complete, consequently, much less of the chloride of 

 lime and sulphuric acid will be required. 

 71 "West Nile Street, Glasgow, 19rt, April 1838. 



On the Bemovalofthe Fetid Odours of Fish Oils* By William 

 Davidson, M.D,, Glasgow, 



The chief objection to the employment of the common fish- 

 oils for burning in lamps and other purposes, is then disagree- 

 able odour, and this is frequently not in propoi'tion to their other 

 qualities. Pale seal oil, for example, is, in general, very trans- 

 parent, and burns well, although its odour is often almost in- 

 supportable. T noticed, in the Edinburgh Journal of Science, 

 several years ago, a process by which the most putrid fish-oils 

 may be deprived of their fetid odour ; and several experiments 

 which have been made, since that period, with dogfish-oil, «fec. 

 of an extremely putrid odour, have tended to confirm these 

 results. The process is cheap, and consists of the use of the 



* Bead before the Society of Ai'tB for Scotland, 30th June 1838. 



