426 
Reports of the Chemical Committee. 
Genuine bone-dust contains about 48 per cent, of phospliate 
of lime, and yields about 4^ per cent, of ammonia, and no 
appreciable amount of sulphate of lime. Good bone-dust at 
present, I believe, cannot be bought for less than 8/. 8s. per ton. 
The bone-dust sent to me by Mr. Broughton was mixed with 
boiled bones, to which frequently sulphuric acid is added for 
the purpose of arresting decomposition. 
June. 
There is at the present time need of very great caution in the 
purchase of Peruvian guano. Samples have been forwarded to 
Professor Voelcker from all parts of England ; for instance, 
from Devonshire, Staffordshire, Nottinghamshire, and Surrey ; 
in each of which the guano, although in some cases coming 
direct from the importers, and being genuine Peruvian guano, 
was damaged by sea-water, contained a considerable proportion 
of sand and rock, and was inferior in value to the best samples 
by 50s. to 60s. per ton. The great number of these guanos that 
have been forwarded for analysis, prove the truth of the warning 
given earlier in the year, that the qualities of guano now arriving 
are so variable and uncertain, that great caution is necessary in 
making purchases of this manure. The following are examples 
of such inferior guanos : — 
Moisture 16-10 
*Organic matter and ammouiacal salts 43'98 
Phosphate of lime 20-73 
Alkaline salts 10-01 
Sand 9-18 
100-00 
* Containing nitrogen 10-65 
Equal to ammonia 12-21 
This guano was sold as " best Peruvian guano," at 14/. 2s. Qd. 
per ton. It is, however, not best Peruvian guano, for it is 
damaged by sea-water, contains too much sand (rock), and yields 
only 12 per cent, of ammonia, and is worth about 21. less per 
ton than Peruvian of average quality. 
Moisture 17-79 
'Organic matter and ammoniacal salts 46-24 
Phosphates 20-21 
Alkaline salts 10-75 
Sand ■ 5-01 
100-00 
* Containing nitrogen ir49 
Kqual to ammonia 13*95 
