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COLLECTIONS AND RECOLLECTIONS. 
Elements which constitute Animals, the air, and the 
water. —Animals are formed of oxygen, hydrogen, nitrogen, carbon, 
and earth. Atmospheric air is formed of oxygen and nitrogen, in 
certain proportions, rendered aerial by the expansive power of heat or 
carolic; it also generally holds in combination a small portion of car¬ 
bonic acid gas, or fixed air. Water is formed of hydrogen and oxy¬ 
gen, in certain proportions : and in its common state it always holds 
a certain portion of earth, and sometimes of carbon, in solution. 
Oxygen, hydrogen, and nitrogen are serial substances, which when 
in a state of separate existence, are termed gases, and, like the air 
we breathe, are invisible, and can only be known by their effects; the 
names or designations which are given to them are derived from the 
Greek or Latin languages, and express, or allude to, their nature and 
properties. 
Thus it is found, that by the affinity which certain substances have 
for oxygen, this element, under certain circumstances, is united to 
them in such a quantity as to convert them into acids : hence oxy¬ 
gen is considered to be the acidifying principle, or generator of acids, 
which the term implies. Oxygen is also the vital air of life, as with¬ 
out it neither animals nor plants can live; it is alsQ a general prin¬ 
ciple of combustion, as without it fire cannot exist. 
Hydrogen, the basis of inflammable air, is a component part of 
water, as the term implies; and it is the lightest of all ponderable 
things. It is hydrogen gas which, when burnt in contact with oxy¬ 
gen produces flame, and gives the brilliant gas-light. It is also this 
gas with which air-balloons are filled; and which, from being so 
much lighter than the atmospheric air, enables them to ascend 
through it. 
Nitrogen is one of the elements of nitre: it is also called azote, 
which implies destructive of life. It is the opposite in nature to 
oxygen, that is, it is incapable of supporting combustion or animal 
life. 
Carbon, which is derived from the latin of coal, is clearly proved to 
be an elementary substance; although, like the aerial elements just 
described, it can only be generally known by. its effects ; for from the 
great affinity it has for oxygen, and also for hydrogen, metallic sub¬ 
stances, and the earths, it cannot be obtained in a pure and free state 
but with great difficulty. The diamond, indeed, is considered to be 
pure carbon, in a state of crystallization, and is the only substance in 
which carbon is known naturally to exist in a separate state. The 
purest state in which carbon can be obtained and exhibited, by the 
common processes of nature and art, is that in which it is combined 
