64 
On Bats' Guano. 
quantity of nitrates together with much nitrogenous organic 
matter is rather remarkable ; the material, however, was light 
and porous, offering free access to air, and, under these cir- 
cumstances, the nitrogen of the fresh excreta would give rise to 
the formation of nitrates. 
The old deposit, although much drier than the fresh, con- 
tained scarcely half the amount of organic matter and salts of 
ammonia, and very much less nitric acid. It was richer in 
phosphates than the fresh deposit, and was unfortunately con- 
taminated with so much sand and valueless earthy matter 
that, unless the cost of transport be moderate, it Avould hardly 
appear worth the expense of exploring the caves in which such 
deposits occur. The fresh deposit, on the other hand, is a valu- 
able manure that probably would realise about 10/. a ton in the 
market. 
I have further submitted to more detailed analyses four other 
samples of Bats' guano, which I have reason to believe were 
taken from caves in Arkansas or Texas, and have obtained the 
following results : — 
Detailed Composition of Bats' Guano. 
No. 1. 
No. 
2. 
No. 
3. 
No. 4. 
27-24 
23 
60 
64 
07 
12-30 
*Organic matter and salts of ammonia . . 
5-83 
8 
26 
21 
57 
30-41 
2-38 
24 
96 
1 
42 
8-33 
8-91 
27 
21 
3 
71 
14-30 
•39 
1 
33 
09 
•34 
3-69 
40 
69 
•45 
2-30 
•44 
4 
03 
99 
5-87 
•80 
6 
75 
3 
20 
9-75 
4-51 
37 1 
'•80 
53 
47 
i-07 
•33 
20 
•48 
•19 
58 
11 
42^19 
2 
15 
3 
31 
16-70 
100-00 
100 
00 
100 
00 
100-00 
•49- 
48 
2 
91 
■ 5-37 
•59 
58 
3 
53 
G-52 
Combining together the acid and basic constituents, the 
composition of these four samples may be represented as 
follows : — 
