Besides these constituents, the fresh manure contains about 2.3 
per cent potash, 3.5 per cent sulphur trioxid, small amounts of iron, 
alumina, lime, magnesia, and silica, and about 83 per cent of organic 
and volatile matter. 
The nitrogen of the fresh manure is present as insoluble organic 
compounds (proteins, chitin), as soluble organic compounds (urea, 
etc.), and as ammonia and nitrates. In the above samples the nitro- 
gen present as ammonia and nitrate averaged 39 per cent of the total 
nitrogen, although it varied between 4.9 and 73.2 per cent. The 
absolutely fresh manure doubtless contains practically no nitrate 
and ammonia, but under certain conditions they are formed rather 
quickly. In absolutely fresh bat manure, urea and insoluble nitrog- 
enous compounds carry most of the nitrogen. 
A certain amount of this fresh material exists in all caves still in- 
habited by bats, the quantity being determined by the number of 
bats and the conditions for conservation obtaining in the cave. In 
most caves the surface inch or 3 inches of the deposit is fresh manure, 
while in certain dry caves where decomposition is slow there is 3 or 
more feet of undecomposed guano in some compartments. 1 In other 
caves the fresh material occurs mainly in piles where the bats congre- 
gate. 
As the fresh bat manure is exposed to water entering the cave, the 
soluble constituents are leached down into the rock (generally lime- 
stone) forming the floor of the cave. The soluble phosphates and sul- 
phates react with the lime, forming the less soluble calcium phosphates 
and sulphate, while the potash and nitrates disappear in the drainage 
water. As the manure decomposes under bacterial action, the or- 
ganic matter is oxidized, with the formation of carbon dioxid, am- 
monia, and nitric, sulphuric, and phosphoric acids. The carbon 
dioxid and some ammonia pass off into the air, while the phosphoric, 
sulphuric, and nitric acids, leached into the underlying stratum, 
react with the lime. When bacterial decomposition and leaching 
are not complete, the resulting product is decomposed guano; when 
they are complete, the resulting product is a phosphatic guano. 
Decomposed guano. — The decomposed guano is generally brown in 
color and pulverulent, with a much higher volume weight than bat 
manure but lower than ordinary soil. It often contains lumps of 
gypsum, organic matter, or fragments of carbonate of lime. The 
composition is intermediate between that of the fresh manure and 
the phosphatic guano. It contains considerable organic matter and 
gypsum. As this is not a well defined material, no maximum and 
minimum figures can be given for the percentages of nitrogen and 
1 All black surface material high in organic matter is not fresh bat manure. In some caves the surface 
1, 2, 3, or 6 inches of material with some undecomposed insects' wings contains only 2, 3, or 4 per cent of 
nitrogen. This shows fairly rapid decomposition of the material in moist caves. 
