202 
GUANO, IN CONNECTION WITH FLORICULTURE. 
of pure water for several hours, then pouring the fluid upon a weighed paper filter, 
and washing the substance with more water till the liquid pass free of colour and 
saline taste. This liquid will be of a pale brown, and pungently salt ; and, being 
tested by littnus-paper, ought to produce the red tint to some extent, indicating 
the presence of a little free acid. By the converse of this experiment, substituting 
yellow turmeric paper for the former, if no change of tint to reddish-brown be 
discoverable, the Guano may be pronounced sound, and free from the alkaline 
reaction of ammonia. 
It is not our object to trespass on the reader's patience, by any particular detail 
of the analytic processes : so far we have proceeded in order to show that Guano 
contains soluble salts, and these to the extent of about two-fifths of the whole 
weight, including that of the combined water separable by heat, The other 
three- fifths consist of dry substances not soluble in water. These proportions are 
assumed only as an approximation, for it rarely happens that two samples are 
precisely similar in their constituents. 
The soluble salts, determined by the re-agency of alcohol, nitrate, or acetate of 
baryta, nitrate of silver, nitrate or acetate of iron, and by ammonia, are, first, 
Urea — that peculiar product which gives to urinous excretions their specific 
qualities, — sulphates of potassa and ammonia, muriate of soda (common salt), phos- 
phate of ammonia, and, occasionally, oxalate of ammonia, and a little muriate 
of ammonia. This comprehensive list, subject to multifarious interchanges and 
modifications, under the agency of the electric vital principle of plants, offers not 
a single ingredient which is foreign to the vegetable organisation. In it are 
contained all the elements of those liquid manures which have been of late years 
advertised, and recommended as nutrimental appliances. Guano has furnished the 
type of all : experimental chemists have easily detected the neutral salts therein 
abounding, and some persons have passed off solutions of such salts, prepared in 
the laboratory, as efficient substitutes. But where shall we trace the urea — -the 
animalised organic matters which float in and give colour to the true solution ? 
This question leads to a cursory notice of the second great process in the 
analysis of Guano, or rather of that series of operations by which are detected and 
fully exposed to view, first, a very considerable proportion— say eighteen per cent, 
—of uric acid, (which in itself combines oxygen, hydrogen, carbon, and nitrogen,) 
united with its small, definite equivalent of ammonia. Secondly, a greater 
proportion of undefined, azotised, solid matter, resolvable by heat, and a very 
powerful re-agent, into a considerable volume of caustic ammoniacal gas, and some 
hydro-carbonous gases. Thirdly, another great proportion of bone-phosphate, in 
a state of much finer division than that to which any process of grinding could 
reduce animal bones ; and, therefore, prepared, with the azotised matter of No. 2, 
to fertilise the soil fully and durably. 
When we consider attentively what a substance true Guano really is, and 
bring the mind to realise its constitution ; taking also into the account that it is 
