226 Dr Davy on some Experiments tending to illustrate 
4th Experiment. Pendulum-rod baked aud varnished (clock in 
dry atmosphere). 
Fast. Rate. Hygrom. Ther. Barom 
1842. : Ve 3 y e In, 
May 27. Noon. 2.0 |0 2.0 20.0 57.5 29.682 
Steet jee 4:0) 108920 20.0 58.5 29.718 
29 6.0 | 0 2.0 17.0 60.0 29.772 
0 |0 2.0 30.0 59.0 29.626 
0 3.0 31.0 61.0 29.622 
0 3.0 | 33.0 58.5 29.944 
0 2.3 25.1 
5th Experiment. Pendulum-rod baked and varnished (clock in 
moist atmosphere). 
Hygrom., 
1842. 
June 3. Noon. 
BO bO G9 BO 9 O98 
0 
0 
5 
0 
5 
0 
6 
bo 
An Account of some Experiments tending to illustrate the 
Formation of Guano. By Joun Davy, M.D.,F.R.SS. Lond. 
& Ed., Inspector-General of Army Hospitals, L.R. Com- 
municated by the Author. 
From the analysis of guano, both of the South American 
and African kind, it appears that this excellent manure con- 
sists mainly of insoluble phosphates, and of nitrogenous 
compounds,—the one, it may be inferred, derived from the 
feces, the other from the urine, of sea-fowl; with this marked 
difference, however, in regard to the latter, that the oxalate 
of ammonia is more abundant in them than the lithate, of 
which, as it is well known, the solid urine of birds is chiefly 
composed. 
