334 TlMEHRI. 
has been subjected to the action of sulphuric acid and 
thus practically resolved into a mixture of sulphate of 
ammonia and superphosphate of lime. It is difficult to 
ascertain how this preference for highly soluble manurial 
substances has arisen — whether from the results of 
properly conducted experiments, or merely due to 
following a fashion set by European countries. Cer- 
tainly the almost complete absence from scientific 
literature of any experimental records bearing on the 
matter leads to the inference that the system of 
manuring at present practised is mainly empirical.* 
Therefore the point it is desired to draw attention to, and 
to help planters to practically determine, is whether the 
highly soluble and expensive manures hitherto employed 
cannot be replaced by others, equally efficient, but more 
economical and more suitable for use in a country like 
this, where the rainfall is so great, the system of drainage 
so perfect, and the soil so acid and ferruginous. 
* In the last number of Timehri is a paper by Mr. Gilzean giving the 
results of field experiments with most of the principal cane manures 
used in the colony. No less than fourteen of these were subjected to 
comparative trial, but only in one or perhaps two instances were the 
manures other than sulphate of ammonia or superphosphate of lime, 
mixed or separate.or dissolved guano, which, as already stated, consists 
practically of the same substances. The results obtained by Mr. Gilzean 
are of course of great value as showing what the usual manures are 
capable of doing, but much fewer experiments would have sufficed for 
this purpose. It is indeed manifest that Mr. Gilzean has been at im- 
mense pains to carry out a remarkable series of supererogative experi- 
ments simply to ascertain the practical effeft of the same mixtures sold 
under different names ; the comparative value of which, or, in other 
words their richness in nitrogen and phosphorus, could have been 
arrived at with greater accuracy, and infinitely greater ease, by a few 
hours' examination in a laboratory, 
