TWENTV-1-1VI-: ^I'lAUS OF CHEMICAL IXVESTIGATIOX. 95 



were smbjectecl to chemical analysis, into the details of which it 

 is impossible to enter here. A few of these latter may be re- 

 ferred to more particularly later on. All branches of the Public 

 Service were aided and all classes of the community. 



Wati:r. 



The water samples analysed— they number, it will be seen, 

 close on 2,000— alTtord an instance not oidy of the value of 

 laboriously adding analysis to analysis, in the plodding way that 

 has already been spoken of, but also of the manner in which 

 the results of analyses of isolated samples, which come to the 

 Government Laboratories from quite extraneous sources, ulti- 

 matel}' become, by careful conservation and methodical collation, 

 aggregated into an investigation of the greatest practical worth. 

 The direct objects of these water analyses have been for the 

 most part to ascertain the suitability of the water eitlier for 

 potable purposes or for use in engine boilers. Of mineral or 

 irrigation waters there have been comparatively few. As to their 

 localities, these waters were procured from places distributed all 

 over the Cape Province, and as to their respective sources, they 

 may be divided into three classes : surface waters, subsoil waters, 

 and deep-seated waters. The results of these many water 

 analyses are card-indexed in the Cape Town Laboratory, and 

 the bulk of them still await the requisite leisure for compilation, 

 comparison, and interpretation, and then codification of the facts 

 revealed. With the records of the potable waters there has 

 hitherto been no opportunity of dealing, and of the boiler waters 

 the indexed results of analyses of the surface and subsoil waters 

 also remain unsystematised. To the figures given by the deep- 

 seated waters alone had there been sufiicient leisure to attend, 

 and the inferences which they enabled me to draw were published 

 in my Presidential Address to the Cape Chemical Society in 

 1908. Of the waters belonging to this class somewhat over 350 

 had been analysed, and comparing the localities whence these 

 were procured with their apparent depth of origin, and so with 

 the geological formation whence they took their rise, the fol- 

 lowing general conclusions were arrived at : — 



1. That the purest deep waters in the Cape Province are those of 

 the Table Mountain and Stormberg series. 



2. That lime and magnesia compounds are far more abundant in 

 the waters of the Karroo system than in those of the older rocks, the 

 Bokkeveld series apparently excepted. 



3. That the Stormberg and more recent Karroo rocks, namely, those 

 of the Burghersdorp series, yield waters containing considerably smaller 

 proportions of chlorides than those of the older Karroo deposits- 



4- That the most saline waters appear to be those of the Uitenhage, 

 Dwyka, and Bokkeveld formations. 



5- That from the waters of the Table Mountain series sodium car- 

 bonate and sulphate are absent, and also, as a rule, magnesium car- 

 bonate ; but that calcium sulphate, on the other hand, is generally present, 

 as well as magnesium sulphate and chloride. 



6. That the waters of the Alalmesbury beds differ from those of 

 the Table Mountain series in containing a larger all-round proportion 

 of salts and in the more frequent presence of magnesium carbonate, 

 and consequent absence of calcium sulphate- 



