244 
present time, in the same manner as the coal formation refers 
us back to a vastly luxuriant vegetation ? Or, was the Guano 
formed under circumstances perfectly similar to those now 
existing; and was nothing required to produce such immense 
stratification, but a long succession of ages ?” AVhen we look 
back to the countless years that must have passed away before 
such accumulations could have taken place, simply by the 
presence of flamingos and cormorants, it certainly gives rise to 
unbounded astonishment. One fact, related by Garsilaso, a 
Spanish author, should be stated. He acknowledges the 
importance of Guano to Peru, and says that under the govern- 
ment of those rulers called incas, in the fifteenth century, it was 
made a crime, punishable by death, to destroy any of the sea- 
fowl that inhabited the Guano islands. This law has, long ago, 
been laid aside ; it indicates, however, the estimation in which 
the substance was held ; and also throws a gleam of light on 
the means of its accumulation. 
It may be asked, why the manure from sea-fowl, which 
abounds in considerable quantities on some of the rocky islands 
in the north of Britain, may not equal Guano ? or why the pro- 
ducts of our own pigeon cotes and hen roosts may not be of equal 
value ? Each of these is known to be a powerful stimulant to 
vegetation, a circumstance which arises mainly from the com- 
bination of the solid and liquid excretions of birds ; but that 
which has been exposed on rocks in Europe has its most 
valuable portions washed away, by repeated rains ; whereas, in 
that immediate part of the globe whence Guano is brought, it 
never rains. The manure is deposited stratum on stratum, 
where it consolidates, dries, and retains all its powerful amo- 
niacal and other ingredients. Again, a wide distinction exists 
between the excrements of carnivorous and granivorous 
animals; between that of marine birds, which live on fish, and 
poultry, which live on vegetables. Who amongst us does not 
know the difference between the offensive gasses arising from 
decaying animal matter, and that of hay, or similar vegetables ? 
These gasses, which have hitherto been suffered to escape, 
and are thereby lost, but which it should be the object of 
the agriculturist to retain — to fix, as it is called, are the very 
essence of manures, and that which, more than any thing else, 
is required for the luxuriant growth of agricultural crops. 
