more lax acceptation of the word in reference to some other bodies, in respect of whom 'twas cold before, and then sensibly hot; because this newly gain'd agitation surpasses that of the parts of our fingers. And in this Instance 'tis not to be overlookt, that oftentimes neither the hammer, by which, nor the anvil, on which a cold piece of Iron is forged, (for all iron does not require precedent ignition to make it obey the hammer) continue cold, after the operation is ended; which shews, that the Heat acquir'd by the forged piece of iron was not communicated by the Hammer or Anvil as Heat, but produc'd in it by motion, which was great enough to put so small a body as the piece of iron into a strong and confus'd motion of its parts without being able to have the like operation upon so much greater masses of metal, as the Hammer and the Anvil; though if the percussions were often and nimbly renewed, and the Hammer were but small,this
