PS Py 
the Formation of Guano. 231 
oxalate of ammonia in guano, or in the urine of the sea-eagle, 
seems to be like that which it exercises on lithic acid, mois- 
tened with nitric acid, in converting it into the purple com- 
pound—the test of lithic acid. The change, as is well known, 
does not take place at common temperatures—a pretty high 
temperature is required to effect it; but I find that, when 
exposed to the direct rays of the sun, it is rapidly effected, 
and that even when the temperature is kept low, by having 
had the platina capsule in which the mixture was made, in 
contact with water. 
In the experiments in which the urine of the sea-eagle was 
exposed to light, moistened, in a limited portion of atmo- 
spheric air, I have stated that the volume of azote remaining 
at its termination, was 36 only, instead of 79, the proportion 
in which it existed at the commencement,—seeming, conse- 
quently, to indicate clearly an absorption of azote. 
Should such an absorption of azote be proved, by farther 
inquiry, to accompany the conversion of the lithate into the 
oxalate of ammonia, in the instance of the formation of 
guano from the excrements of birds, it will be an interesting 
fact in the economy of nature, and may help, with the gene- 
ration of nitre, to account for there being no change, as far 
as has hitherto been determined by experiments, in the com- 
position of the atmosphere ;—the great principles of equili- 
brium being, on the part of vegetables, the separation of 
carbon, and the evolution of oxygen from carbonic acid gas, 
the product of combustion and respiration ;—on the part of 
disintegrating rocks, such as contain alkali and lime, and of 
the excrements of birds, and probably of animals generally, 
undergoing decomposition, the absorption of azote—its sepa- 
ration from the atmosphere, to form either nitre or ammonia ; 
designed, in their turn, to fertilize the soil, and promote 
vegetation. 
Tue OAKS, AMBLESIDE, 
December 30. 1844. 
