The power by which the parts of bodies are kept together. It is a phenomenon the most common, but the least understood. Newton derides the hooked atoms, by means of which it has been attempted to explain coherence; for it still remained to be known why they are hooked, and why they cohere. He treats with no greater respect those who have explained cohesion by rest. “It is,” says he, “an occult quality.”
He has recourse to an attraction. But is not this attraction, which may indeed exist, but is by no means capable of demonstration, itself an occult quality? The grand attraction of the heavenly bodies is demonstrated and calculated. That of adhering bodies is incalculable. But how can we admit a force that is immeasurable to be of the same nature as one that can be measured?
Nevertheless, it is demonstrated that the force of attraction acts upon all the planets and all heavy bodies in proportion to their solidity; but it acts on all the particles of matter; it is, therefore, very probable that, while it exists in every part in reference to the whole, it exists also in every part in reference to cohesion; coherence, therefore, may be the effect of attraction.
This opinion appears admissible till a better one can be found, and that better is not easily to be met with.
Last updated Tuesday, August 25, 2015 at 14:14