Juf't fo it is with the whole fyf'tem of nature. You cannot take up any parcel of matter and fay of it, This has efi'ential feparate properties, which impower it to be a natural agent. A philofopher ought to confider it as a concrete, with a certain difpofition of its parts, liable to be acted upon by the fubtiler parts of the machine, which cannot be ref'trained from it by art. And it may as juf'cly be alledged, that it is the eitential property of animal fubf'tances to live, or of vegetables to fpring, as it can be laid, that it is the efi'ential proper ty of the loadf'tone to attract. Nothing therefore can be more conducive to the promoting a true acquaintance with the operations of nature, than to confider what are, and What are not the efiential properties of the firf't principles of matter.