Sous of the South-Western Districts of the Cape Colony. 127 
soils of the locality, and in the following table one may see to what 
extent soil exhaustion had gone on. 
Average composition per cent. of 
Virgin Soils. Cultivated Soils. 
Was aes th veut Ph. 291 194 
@nasiaye ti. leas. "133 127 
Phosphoric oxide... 031 ‘015 
In other words, the soil had been exhausted of 097 per cent. of 
lime, ‘006 per cent. of potash, and :016 per cent. of phosphoric 
oxide. Roughly we may say that cultivation had removed from 
each acre of the surface soil 1,940 lbs. of lime, 120 lbs. of potash, 
and 320 lbs. of phosphoric oxide. To look at the matter from 
another point of view : for every pound by weight of lime removed 
from the soil by a crop of wheat, 4 lbs. of potash, and 3 lbs. of 
phosphoric oxide are needed; relatively to the other plant-food 
constituents of the soil, therefore, as well as absolutely, the amount 
of phosphoric oxide, meagre enough even in the virgin soils, had 
been halved in the process of cultivation; the crops were, in fact, 
starved in respect of this one essential nutritive element, and were in 
consequence quite unfitted to resist the attacks of parasitic diseases. 
Before proceeding with the actual details of the work done it may 
be advisable to say a word or two on the general subject of soil 
analysis. It may possibly appear superfluous to dilate on the use 
and benefits of analyses of soils when addressing a Society such as 
this, and yet I am by no means sure that it is so, for there have not 
been wanting men of scientific repute who have not only cast doubts 
upon, but have even openly ridiculed the worth of such investi- 
gations. Thus a well-known author, who has given much informa- 
tion to the world on agricultural industries as carried on in the 
Australian and South African colonies,* ‘‘does not hesitate to affirm 
that the subject of analysis of soil has occupied quite an exaggerated 
position of importance, not only with the unlearned, but also 
among those who ought to have known better. One individual,”’ 
this author proceeds to observe, ‘‘ often of no repute in the scientific 
world, resolutely and dogmatically takes the lead, and many follow, 
sheep-like, without inquiry. This has been painfully the case in 
connection with soil analyses. . . . It is quite impossible to deter- 
mine with certainty in the laboratory, or by any other test than the 
growth of crops upon it, whether an ordinary agricultural soil is 
good or inferior.””’ Again t—-‘‘ No analyst, using the ordinary processes 
* Wallace: Rural Economy and Agriculture of Australia and New Zealand, 
pp. 167, 168. 
+ Wallace: Op. cit. p. 169. 
