296 
On the Analysis of Guano. 
hydrochloric acid be expelled, and the greater part of the water. Alcohol 
of 0"8S0 is now poured upon the pasty residuum, and the whole, after 
being well stirred, is thrown upon a filter. The phosphoric acid passes 
through, as also the magnesia in union with sulphuric acid. The sul- 
phate of lime, which is quite insoluble in spirits of wine, being washed 
witii them, is dried, ignited, and weighed. From the weight of sulphate 
of lime, the quantity of phosphate of that earth that was present becomes 
known. 
12. Ammonia in excess is now added to the filtrate, which throws 
down the granular phosphate of ammonia and magnesia. After washing 
and drying this powder at a heat of 150°, its w^eight denotes the quantity 
of that compound in the guano. 
13. To the filtered liquor (of 12), if a little ammonia be added, and 
then muriate of magnesia be slowly dropped in, phosphate of ammonia 
and magnesia will precipitate, from the amount of which the quantity of 
phosphoric acid may be estimated. 
14. The proportion of oxalate of lime is determined by igniting the 
washed residuum (of 9), and placing it in an apparatus for estimating 
the quantity of carbonic acid given off in dissolving carbonate of lime. 
The apparatus, either Fig. 1 or 2, described in my little treatise on alka- 
limetry, will serve that purpose well. I have rarely obtained more than 
^gr. of carbonic acid from the insoluble residuum of 100 gr. of good 
guano; and that corresponds to less than IJ percent, of oxalate of lime 
in the guano. Sometimes no effervescence at all is to be perceived in 
treating the washed residuum with acid after its ignition. 
15. The carbonate of ammonia in guano is readily determined by 
filtering the solution of it in cold water, and neutralizing the ammonia 
with a test or alkali metrical acid (See the Treatise on the Alkalimeter 
above referred to). 
16. Besides the above series of operations, the following researches 
must be made to complete our knowledge of guano. The insoluble re- 
siduum (of 10.) which has been deprived by two successive operations 
of its uric acid and ammonia, may contain azotized organic matter. It 
is to be therefore well dried, mixed with five times its weigiit of the 
usual mixture of hydrate of soda and quicklime, and subjected to gentle 
ignition in a glass or iron tube closed at one end, and connected at the 
other with an ammonia-condensing apparatus. The amount of ammonia 
being estimated by a proper ammonia-meter, represents the quantity of 
azote, allowing 14 of this element for 17 of ammonia, being the poten- 
tial ammonia corresponding to the undefined animal matter. In a 
sample of Peruvian guano, I obtained 5 per cent, of ammonia from this 
source. 
n. The whole quantity of ammonia producible from guano is to be 
determined by gently igniting 25 grains of it, previously well dried, and 
then mixed with ten times its weight of the mixture of hydrate of soda 
and quicklime (2 parts of the latter to 1 of the former). The ammonia 
disengaged is condensed and measured as above described. 
18. The ready-formed ammonia is in all cases determined by distilling 
a mixture of 100 grains of it with 50 grains of slaked quicklime, con- 
densing the disengaged ammonia, and estimating it exactly by the meter. 
19. The relation of the combustible and volatile to the incombustible 
