128 The Transactions of the South African Philosophical Society 
substance : it purifies and refines it also by recrystallization, until it 
sometimes produces an article as pure as any made by a chemist. 
It may appear somewhat strange that the little rock rabbit should 
have been capable of supplying the raw material for such quantities of 
nitrates and nitrate-bearing soil as occur in these mountains. 
The conditions for the formation of nitrates exist in almost all our 
mountains, not excepting those of the Peninsula. In caves that are 
inhabited by rock rabbits, the nitrification of their refuse is proceeding, 
especially in summer, on Table Mountain as well as in the Karroo and 
on the banks of the Orange River. But the nitrates cannot accumulate 
here, because every winter washes away what was formed during the 
summer. Hence, it is not surprising that samples of such soil from 
Table Mountain usually do not contain more than 4 per cent. of nitrates 
of calcium and potassium. 
In those dry regions, however, the climate allows the accumulation of 
the feces of the rock rabbits from year to year, from century to century, 
from thousands to thousands of years, just as it favoured the preserva- 
tion of the guano on the islands along our western coast. And all this 
time the nitrification, the lixiviation, the crystallization and recrystal- 
lization, went on, until cliffs hundreds of yards long were saturated 
with nitrates, and thousands of tons of nitrate-bearing débris had 
accumulated under their shelter. 
Printed by West, Newman & Co., Hatton Garden, London. 
