11 



acid resins, the potassium salt of one being mostly insoluble in an excess of 

 alcoholic potash, while the other is soluble. 



Dr. Henry's paper (loc. cit. p. 1145), contains the following statement : — 

 " There also appears on the market from time to time a similar resin, which, since 

 it is exported from Australia, is commonly known as ' White Pine resin,' or 

 ' Australian sandarac' This substance is the natural exudation product of 

 Callitris verrucosa, and differs from the common sandarac chiefly in the larger 

 size of the tears and its smaller solubihty in alcohol." 



This statement may be taken as representing the generally accepted idea 

 in Europe regarding Australian sandarac, and Tschirch (" Die Harze und die 

 Harzbehalter," p. 535), also gives similar information. These authors are, however, 

 in error as regards the origin of the resin, because Australian sandarac is not 

 collected from C. verrucosa to any great extent, if at all, for occurring as it does 

 in the far interior of the States, the difficulty of getting the product to market 

 naturally acts adversely to the collection of its resin. 



The sandarac so far exported from Australia has been collected from 

 various species, and this is also indicated by the " larger size of the tears, and its 

 less solubility in alcohol " than ordinary sandarac, as mentioned in the above 

 statement. The resin of C. calcarata is, perhaps, the least soluble in alcohol, of 

 all the Callitris resins, but the exudation of some species is far more soluble in 

 alcohol than is ordinary sandarac, and, as will be seen from the table below, 

 C. verrucosa is one of the more soluble of these resins. 



While Australian sandarac continues to be collected from various species of 

 Callitris, the commercial product will be found to be somewhat variable, particularly 

 as regards solubility. Three samples of resin of C. arenosa in our possession 

 have a striking resemblance to African sandarac, and are even more soluble in 

 alcohol than the Museum samples of African sandarac tested at the same time 

 for comparison. These samples were originally received at the Museum as 

 " sandarac, ist quality," " sandarac, 2nd quality," and " picked Mogadore san- 

 darac." This last specimen is a portion of a " lot " which was sold in London 

 in October, 1894, at 70s. per cwt. It was indeed difficult to detect any 

 difference between this last sample and that of C. arenosa collected at Ballina, 

 Northern New South Wales, either in hardness, density, colour, transparency, 

 reactions with alcoholic potash, or in general appearance ; only that the solubility 

 in alcohol is in favour of the resin from C. arenosa. Supporting the results of 

 solubility in alcohol as shown by the appended table, i gram each of the resin of 

 C. arenosa and Mogadore sandarac in tears, nearly the same size as possible, was 

 added to 20 c.c. go per cent, alcohol, the whole of the tears of C. arenosa were 

 dissolved before those of the sandarac. The acid numbers, too, of the resins 

 closely agreed, that of the Mogadore sandarac being 151, and that of the sandarac 



