51 
then proceeds to infer that repulsions, as well as attractions, 
must follow the same law, that a body in equilibrium will re- 
main so, if the bulk be reduced to one-eighth, or the distance 
of all the molecules to one-half ; and hence that matter can 
offer no resistance to compression. The conclusion, he re- 
marks, is absurd. This absurdity, however, does not strike 
him as proving the utter falsity of the premise from which it 
is logically derived. On the contrary, he sets it down merely 
as one added pi’oof that the nature of matter and of force is in- 
conceivable. 
That many other laws of force have been assumed, and their 
mathematical results developed, is one of the most familiar and 
patent facts in the history of dynamics. Five whole sections 
of the first book of the Principia are occupied with calculations 
of this very kind. The premise, then, in this reasoning is a 
clear historical falsehood, and the conclusion, as Mr. Speucer 
himself admits, plainly absurd. In the third edition of his 
work, after fifteen years, the paragraph has been silently with- 
drawn. But no explanation has been given how this double 
inversion of fact and logic was left so long standing sentinel 
in the porch and gateway of the new material philosophy. 
Gravitation, then, is no blind necessity, but a law of natui’e, 
proved by a combination of expei’ience and deductive l’easoning, 
and which thus implies and requires the choice of a Divine Law- 
giver. But is it mediate or ultimate ? If mediate, so as to 
have some other physical cause, what is the medium on which 
it depends ? If ultimate, which is the true conception of it, 
universal attraction, or universal appetency ? Hei’e we find 
the nucleus of certain truth surrounded by a large and ample 
nebula of mere theories and doubtful speculations. 
Newton has been careful to remark that he gives no decision 
on the physical cause of gravity, if such there be. "I use 
the words,” he says, “attraction, impulse, or propensity, 
promiscuously and indifferently one for another. Wherefore 
the reader is not to imagine that by these words I anywhere 
take on me to define the kind or manner of anv action, the 
causes or physical reasons thereof, or atti’ibute forces in a true 
and physical sense to certain centres, when I speak of them 
as attracting, or endued with attractive powers .” 
Gx’avitation, if a mediate result, can hardly be attractive. 
For this would l-equire us to conceive a line physically con- 
necting evex-y pair of masses or atoms in every varying posi- 
tion, and exercising a contractile power to bi’ing them nearer. 
Also that the conti'actile force should be increased, after it has 
brought them nearer, and not, as in every known case of the 
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