374 Quarterly Reports of the Chemical Committee, 1881. 
Fourteen per cent, of sulphate of ammonia, the minimum 
quantity guaranteed, contains 3"6 per cent, of ammonia, or 
1 per cent, more than was found in the sample analysed by 
Dr. Voelcker ; the percentage of soluble and insoluble phos- 
phates satisfy the demands of the guarantee, it being understood 
that the lower figures alone are binding. Attention also is 
directed to the statement that the vendor guarantees nitrogen 
equivalent to a minimum of 14 per cent, of sulphate of ammonia, 
or 17 per cent, of nitrate of soda, but not both together. 
Measuring its value by the minimum figures quoted above, 
this manure is not worth more than from 5/. 5s. to 5Z. 10*. 
a ton. 
2. Mr. Robert Lake, Oakley, Rochester, sent Dr. Voelcker 
a sample of British guano, of which he bought, without a gua- 
rantee, two tons at 3/. per ton from Messrs. Jones and Co., 
Mark Lane, manufacturers. 
The following is the composition of this sample of British 
guano : — 
Moisture 15 "15 
"Organic matter 31 " 55 
Phosphate of lime 2 "84 
Oxide of iron and ahimina 4 "25 
Carbonate and sulphate of lime, &c 27 "83 
Insoluble siliceous matter 18 • 38 
100-00 
* Containing nitrogen 1 • 50 
Equal to ammonia I '82 
A better manure than this British guano would be obtained 
by adding 25 per cent, of mineral superphosphate to one ton 
of shoddy. Good shoddy, yielding from 5 to 6 per cent, of 
ammonia, can be bought at about 50s. to 60s. per ton ; and 
superphosphate, guaranteed 25 per cent, soluble phosphate, at 
4/. per ton. 
Accordingly, one ton of shoddy, costing 50s., and 5 cwt. of 
superphosphate, costing 20s., will give a manure which costs 
2/. 16s. per ton, and which contains about 5 per cent, of ammonia 
and 6 per cent, of soluble phosphate of lime. In other words, 
one ton of the mixed shoddy and superphosphate would be 
worth fully as much as two tons of British guano. 
3. Mr. Robert Lake also sent a sample of Davis's Patent 
Manure, of which ho bought three tons at 6/. per ton from Messrs. 
Henry Wright and Son, Town Wharf, Maidstone, agents in 
Kent for Davis and Co.'s Patent Manures. 
On analysis, the sample sent by Mr. Lake showed the follow- 
ing composition : — 
