329 
plant, rather than believe it to be drawn awrty by the 
attractive force of the gases to which it was expo- 
sed. 
631. If we may be allowed to venture an opinion 
upon a difficult question in chemical doctrine, we 
would beg to remark, that chemists appear to have 
ascribed too much to the attractive, and too little to 
the repulsive forces, exerted between the particles of 
bodies. In artificial experiments, they generally ef- 
fect decomposition by the employment of agents 
which exert a superior attractive force towards one 
or other of the elements of the compound ; and the 
decomposition may then be truly said to be accom- 
plished by the energy of attraction. But decomposi- 
tion occurs, likewise, spontaneously in bodies, where 
no particular attraction is exerted by the surrounding 
bodies, and where, therefore, the first movements 
towards change must arise in the bodies themselves. 
By these spontaneous movements, the composition of 
the existing compound is subverted, and its separated 
elements are then at liberty to enter into new combi 
nations with each other, or with the bodies which 
surround them. Hence the decomposition of a bo- 
dy may be effected either by the superior attraction 
exerted towards one or more of its elements by some 
other body ; or it may proceed from a spontaneous 
change in the natural affinities of the elements of the 
body itself, in which case the separation of its parts 
may more properly be said to arise from repulsion 
than from attraction. 
632. All the phenomena of spontaneous decompo- 
sition appear to us, indeed, to suggest the belief, that 
