Pkideaux. — On Kauri-resin. 369 



North Island. Besides being dug out of the ground, a good 

 deal of it is gathered fresh from the standing trees, where it 

 has oozed out of the bark. "When dug from the ground it is 

 scraped free of earth and shipped away in that condition, no 

 attempt having been made to deal with it here to my know- 

 ledge, except by the syndicate mentioned above. 



I have looked up the "Transactions of the New Zealand 

 Institute," 1869 to 1900, and found next to nothing about the 

 chemical properties of this resin. I found a good many 

 articles on the behaviour of other resins in the back numbers 

 of the " Journal of the Chemical Society," of which the years 

 from 1870 to 1872 and 1882 to 1900 were accessible to me ; 

 but, unfortunately, the number which a dictionary of 

 chemistry gave as containing an investigation of kauri-resin 

 was not to be found. 



Among the books which I have most used are Ostwald's 

 " Physico-Chemical Measurements"; Allen's "Commercial 

 Organic Analysis," 1886; "Lubrication and Lubricants," 

 Archbutt and Deeley, 1900; " Destructive Distillation," Mills, 

 1886 ; and Sutton's "Volumetric Analysis." 



There are two main varieties of kauri-resin — the fresh resin 

 as it hardens on the tree, which is generally white or trans- 

 parent, and the fossil resin. The appearance of the latter 

 ranges from transparent to opaque, from white to yellow. 1 

 used for my distillation the purest fossil resin, obtained from 

 carefully scraped lumps roughly powdered. For finding the 

 bromine-absorptions I used the method of Mills,* first making 

 sure of the results by finding the absorption of a known oil 

 (olive). My reason for using the bromine method rather than 

 the iodine was that a solution of bromine in carbon-disulphide 

 is not so complicated to make up as the solution of iodine- 

 chloride. It is doubtful, besides, whether any results could be 

 obtained from a resin in a reasonable time with the iodine 

 solution. Mills has determined the absorption of kauri-resin 

 to be 108-2. He has not stated the variety of resin which he 

 used, but I got values much higher than this for all varieties. 

 Mills has also noticed that hydrobromic acid is always 

 formed, but gives no figures for it. I have given figures in 

 most cases. The method I adopted was to decant the 

 aqueous part of the solution after the reduction with Na 2 S. 2 3 , 

 wash the CS with w r ater two or three times, adding the water 

 to the part first poured off, then add methyl orange and titrate 

 with decinormal NaOH. After this was done I added phe- 

 nolphthalein and titrated with decinormal NaOH for organic 

 acids. The values found were nearly the same with very 



* Allen's " Commercial Organic Analysis," " Resins " ; edition, 1886. 

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