Annual Report of the Consulting Chemist. 
their rights to export the guano. At first there was hardly a bird 
to be seen on these islands, but, by protection at the breeding 
season, in the course of twenty-three years the birds have multi- 
plied to such an extent that they are now obliged to settle on 
adjacent islands. The birds remain on these islands about nine 
months. They begin to lay as soon as sufficient dung has accumu- 
lated to serve as nests for the eggs. After the hatching season is 
over, and the birds are strong enough to shift for themselves, 
they leave the island — generally about March — and return again 
in June. During the interval the excrements are collected, and 
at once pitted and placed ready for shipment. The nests of 
the guano-birds thus appear to be made by their burrowing in 
the sun-dried and hardened birds'-dung. If, as on very rare 
occasions, rain intervenes, the nests get wet and the eggs are 
destroyed. The present supplies of Ichaboe and Saldanhay Bay 
guano, it will thus be seen, are the dried recent excrements of 
sea-fowls, which feed upon the enormous quantities of small fish 
that frequent the waters surrounding these guano islands. The 
fact that the guano is collected in localities rarely visited by 
rain, and before the recent deposits have undergone deterioration 
by dampness of the air or other influences, explains the presence 
of a high percentage of nitrogen, and the superior fertilising 
value of the present importations of Ichaboe and Saldanhay Bay 
guano. Most shipments are made to Leith, and the guano finds 
a ready sale in Scotland, as it is rich in nitrogen and phosphates, 
and is in a fine and dry condition. Different cargoes of the 
recent dry birds'-dung, I am informed, seldom contain less than 
from 13^ to 16 per cent, of ammonia. 
A sample of Saldanhay Bay guano recently analysed by me had 
the following composition ; — 
Moisture 22-25 
*Organic matter and salts of ammonia 37 '43 
Phosphate of lime 18 • 24 
f Alkaline salts 3*59 
Insoluble siliceous matter 18 - 49 
100-00 
* Containing nitrogen 9 ■ 29 
Equal to ammonia 11 "28 
t Containing soluble phosphoric acid .. .. "99 
Equal to tribasic phosphate of lime . . . . 2 • 02 
Total percentage of phosphoric acid . . . . 9 ' 35 
The guano was dark-brown, and had a strong pungent smell, 
which is partly due to volatile carbonate of ammonia. 
Ichaboe guano, as now imported, has a light-brown or yellow 
colour, and generally is mixed with a good many feathers of the 
birds that produce the deposit. 
