Mode of redsoning in Chemistry. 351 
heat, to convert solids into fluids. Here he is forced to stop, 
and can assign no reason why heat produces this effect. 
Some, however, not considering that they have done enough, 
and all they can do, when they have traced a phenomenon 
to one of the foregoing ultimate agents, and shown that it is 
analogous to other well known effects of that agent, attempt 
a farther explanation by saying, that heat melts snow because 
it separates its particles so far asunder as to allow of that 
freedom of motion, which is essential to fluidity. But I can 
see nothing satisfactory in explanations of this kind. Fluidi- 
ty is something more than a mere separation of the particles 
of matter.. For, in the first place, such a separation of the 
particles does not uniformly accompany liquefaction. Water 
is denser than ice. In the second place, were liquefaction 
always attended with a diminution of density, we should even 
then be unable to trace any connexion between this eircum- 
stance and the properties of a fluid. There are bodies much 
rarer than water, as cork, which are still solid. 
In the same manner, the only account we can properly give 
of the phenomena of combination and decomposition, is 
point out their conformity with the laws of attraction ; which 
laws are nothing more than the modes in which this ultimate 
agent has been found, by experiment, to operate. — If the che- 
mist supposes that his explanations of individual cases 
ef combination or decomposition amount to any thing 
more than this, he will find himself mistaken. It is a law of 
attraction, that is, it is a general fact, ascertained by experi- 
ment, that bodies have different degrees of affinity for each 
other. This principle is deduced from the fact, that in some 
cases the elements of a compound are so strongly united that 
they can scarcely be separated by any means mn our power; 
while, in other cases, the union is so slight that it is easily 
overcome, or the elements even separate spontaneously. 
Hence, in an individual case of decomposition, as when cam 
hor is precipitated from its solution in alcohol, 
has a stronger attraction for it than the camphor has. vipe 
account, if it be considered as a full explanation of _ 
nomenon, there is something very much of the nature of rea- 
soning in a circle. The only proof we have me water has 
a : whe aha * 
a stronger attraction for alcohol than camphor has, 
fact that it takes it from water. The fact is therefore 
