iv Transactions of the South African Philosophical Society. 



Note on the Discussion of the errors of certain types of minimum 

 spirit thermometers in use at the Eoyal Alfred Observatory, Mauritius, 

 by A. Walter, F.E.A.S., Chief Assistant. 



The conclusions arrived at are : — 



(1) The minimum thermometers (even the so-called '' sensitive ") 

 should never be used as ordinary thermometers. 



(2) The errors from comparisons at certain temperatures may be 

 as much as 2°. 



(3) The absolute minima obtained with the spherical bulb thermo- 

 meters may amount to as much as + 3°. 



Dr. B. VAN DER EiET read a paper on *' The Chemical Composition 

 of Berry Wax." 



In this paper the author drew a comparison between constants 

 found for berry wax (from berries of Myrica cordifolia) and those 

 quoted for myrtle wax (from berries of various species of Myrica), 

 by Dr. J. Lewcowitsch in his treatise on the Chemical Analysis of 

 oils, fats, and waxes. Seeing that for berry wax the iodine value was 

 found, by Hiibl's method, to be nil, the possibility was suggested that 

 the former had based his statement that myrtle wax contained oleic 

 acid, as well as the glycerides of stearic, palmitic and myristic acid, 

 on a bromine value, and not on a directly obtained iodine value 

 which alone would be conclusive proof of the presence of unsaturated 

 acid, such as oleic acid. He recommended berry wax for use in the 

 oil bath on account of its stability at high temperatures (300° C) 

 and high flash-point. 



Note on " Crushed Granite as Fertiliser." 



Dr. VAN DER EiET Said, with regard to the value of crushed granite 

 as fertiliser, that as yet no full analyses of granites of the Western 

 Province had been published, although granitic soils had been analysed 

 by special methods for determining amount of available plant-food. 

 He hoped to be able to give the Society on a later occasion the results 

 of certain analyses of granites which he had in hand. The report 

 that granite dust had been successfully employed as a fertiliser in the 

 U.S. of America w^as to be received with caution, at any rate as 

 regards the statement that a ton of crushed granite would contain 

 fertilising substance valued at £20. Granite usually contained at 

 most Q'b per cent, potash, which would be the valuable ingredient, 

 the potash being present in orthoclase felspar. Even a ton of 

 crushed orthoclase would not contain more potash than could be 

 bought for £3 or £4 in Cape Town. The report regarding crushed 

 granite as a fertiliser was possibly a twisted version of Bulletin 

 No. 92 of the Bureau of Chemistry of the U.S. Department of 

 Agriculture, there being a very interesting article in that Bulletin by 

 A. S. Cushman on " The Effect of Water on Eock Powders." 



