t '95 ]

CHAPTER XIV.

Experiments and observations tending in their progress to Jhow, thatthe subtile fluid, which has been discovered in all bodies, is probablynothing more than the particles of that matter, which is diffused innever-ceasing rays from the fun to the earth, and likewise to every

part of the solar system.

XPERIENCE and observation, the two great guides to

. JLL/ human knowledge, have convinced us, that there is dif-fused within the substance, and on the surface of all bodies, whe-ther animal, vegetable, or mineral, a certain flu'd, which somehave called æther, some phlogiston, others the sulphureous prin-ciple, the inflammable substance, the electric fluid, or the ele-mentary fire.

It has been a dilpute of some standing, whether fire be a lpe-cific substance, originally distinct from all other bodies, or whe-ther it be only common matter put in motion.

Lord Verulam, from a variety of particulars, maintains, thatheat in bodies is acquired by motion ; and that to produce heat,you have only to cause a friction ' between bodies.

Boyle follows this great man, and maintains that fire may bemechanically produced, by a violent agitation of the parts ofbodies -, and he endeavours to maintain his doctrine, with manyexperiments and observations a .

This

To come to the productions of heat, wherein there appears nothing on the part

1 Bacon’s Treatise, De forma Calidi, &c.1 Shaw’s Boyle, vol. i. p. 564.

of