30 PRESIDENTIAL ADDRESS. — SECTION II. 



ment, Pretoria ; Mr. H. Ingle, late of the Agricultural Laboratory 

 at the same place ; Mr. J. S. Jamieson, of the Government Labora- 

 tory, Durban, Natal ; and my own colleagues, Messrs. J. Lewis 

 and J. G. Rose. 



Investigations in agricultural chemistry have likewise not been 

 barren of results. Dr. W. F. Sutherst, of Uitenhage. has been 

 busy investigating the stimulating action of manganese compounds, 

 when applied to the soil, on plant growth. In my own laboratory 

 investigations into the composition of Colonial cereals have been 

 undertaken by Mr. Lewis, who has also begun some experiments 

 with a view to ascertain any peculiarities of chemical composition 

 arising in the bones of animals affected by " lamziekte." To 

 another phase of that subject Mr. Ingle, of Pretoria, also devoted 

 some attention, and deduced very interesting results. Mr. Ingle 

 has also shown the insufficiency of Dyer's method of soil extraction 

 as an adequate gauge of the fertility of different soils, inasnmch 

 as it takes no account of the rapid renewing of immediately avail- 

 able plant food after it has been extracted by growing crops.* 

 Personally I have resumed — although, it must be confessed, rather 

 tentatively — a long-dormant investigation into the food values of 

 various fodder plants grown in the Cape Colony. All these, and 

 there are others besides, are but as a drop in the bucket, and out 

 of all comparison with what still awaits doing. 



If we turn to mineralogical chemistry, to judge from the published 

 records, the amount of original work done in South Africa has been 

 sparse indeed. Occasionally a previously undescribed mineral is 

 found and analysed, but even of these analyses the greater number 

 have been performed in Europe. As typical of the class of analysis 

 that I am now referring to may be mentioned the melilite-basalt 

 from Spiegel River, Cape Colony, which was analysed by Mr. 

 Lewis some years ago.f and the saltpetre from the cave sandstone 

 of the Stormberg beds.t Mr. Lewis has also analysed a zeolite 

 which is found in a lava near Barkly, in vesicles of which its v/hite 

 fibrous radiating crystals occur. This is one of the minerals that I 

 have alluded to as probably new to science, and it possesses the 

 same composition as scolecite (CaO.ALOs (Si02)3 4-3H.20). although 

 differing from the latter mineral physically and optically. § 



There is one branch of analytical chemistry wherein a fair 

 amount of work is being done in this country, albeit of a more or 

 less routine character. The chemistry of foods is for mankind 

 undoubtedly of paramount importance, all the more on account 

 of the ingenuity with which sophistication is practised at every 

 turn. Dr. W. Ledlie, now of Surrey, was the first to take up the 

 work of regular food analysis in South Africa, nearly twenty years 

 ago, a work which, in the adjacent colony, devolved on myself 

 about four years later. Since then many thousands of comestibles 

 of all sorts have been analysed, with results not alwa^-s apparent 

 on the surface, but be\'ond a doubt most salutarj' in their effects 



* Trans. Chem. Soc, 1905, Vol. S/, p. 43. 



t ^-G.H. Geol. Commission Report, 1903, p. 51. _ 



X Ibid., 1904, p. 106. 



§ Vide C.G.H. Geol. Commission Report, 1904, p. 134. 



