THE CONSTITUTION OF MATTER. 
411 
are; to seek for other phenomena of a simpler and yet more general nature, 
which are considered to be what are usually denominated the “ causes.” 
To what extent this endeavour has been successful it is difficult to ascertain, 
much more to express. According to all probability, in this search after causes, 
we pursue a will-o’-the-wisp, which possesses no real existence,—a difficulty, in¬ 
deed, presenting itself at the outset, it having even been found impracticable to 
explain or define accurately what is meant by the term “cause.” The philoso¬ 
phers who have through ages applied themselves to the study of effects and 
causes, seem to have neglected this fundamental inquiry. In connection with 
such a study, it would be worth consideration whether the entire universe may 
not be the great proximate and ultimate cause of itself; every fraction of it ex¬ 
ercising such an influence upon every other fraction, and, upon the whole, as to 
be indispensable to the existence aud integrity of the natural order of things. 
However, this may be, the chemists and physicists, even before the departments 
of science which they respectively practise assumed independent existence, 
have ever been looking, like the rest of mankind, for what they suppose to be 
the causes of the phenomena which they specially study. As they occupy them¬ 
selves with matter and its associated qualities, it has arisen that they have de¬ 
voted all available ingenuity to the explanation of the sensible properties of 
matter by speculations as to its ultimate and final constitution. The oldest of 
the theories founded on such speculations is that which has held its ground the 
longest; not altogether because it is perfect and unassailable, but chiefly, as I 
shall endeavour to show, from its possessing this recommendation, that it makes 
use of things which we can see and touch, in order to represent and symbolize 
things which cannot be thus tried by the test of the senses. 
The mind constantly endeavours to account for unfamiliar phenomena, by 
drawing a parallel between them and others which are more perfectly under¬ 
stood. According to the view referred to, all kinds of matter are imagined as 
composed of “ massy, hard, impenetrable, moveable particles, of such sizes and 
figures as best conduced to the end for which they were formed.” this atomic 
theory, in its physical phase, was known, literally, ages ago ; it was a subject 
which occupied the discussions of the Greek, and even the Hindoo philosophers ; 
it is referred to by Newton in the often-quoted passage in his ‘Opticks;’ 
but it was reserved to Dalton, at the beginning of the present century, to revive 
the problem and to perceive how the idea of atoms or finite particles might 
be applied to the explication of the phenomena of chemical combination. Not¬ 
withstanding, however, the great credit due and awarded to Dalton for his 
acuteness, it was only by the discoveries of observers subsequent to him that 
the hypothesis was consolidated into a theory of stability. The only experi¬ 
mental data possessed by Dalton were the facts that the instances then known 
of chemical combination exhibited the definite character, which has since been 
traced out in thousands and tens of thousands of cases. I hey were limited to 
such combinations as the oxides of carbon, nitrogen, sulphur, and those of a few 
of the metals, and were based upon analyses which, although pretty good con¬ 
sidering the state of chemical knowledge at the time, were, nevertheless, ex¬ 
tremely inaccurate. The data for the law of multiple proportions were in the 
hands of several chemists before Dalton’s time, particularly Proust; the law of 
reciprocal proportions was also partially discovered, but never enunciated, in 
the last century by Richter ; we cannot therefore help admiring the clear-seeing 
sagacity, as well as the boldness of Dalton, in giving to the world an explanation 
which so mauy had failed before him to perceive. It must, however, be con¬ 
fessed that the conclusions of Dalton’s own mind were maintained by him some¬ 
what dogmatically, when we consider what is really the truth, that his theory 
does not follow as a logical necessity from the facts known to him. 
We have learnt from observation, and a long series of thousands of experi- 
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