or hinder the artificial Production of Cold by particular Agents, but, which will seem more strange, some unobserv'd, and perhaps hardly observable, Indisposition in the Patient may promote or hinder the effects of the grand and Catholick Efficients of Cold, whatever those be. This suspicion I represent as a thing that further experience may possibly countenance, because I have sometimes found, that the degree of the Operation of Cold has been much varied by latent Circumstances, some bodies being more wrought upon, and others less, than was upon very probable grounds expected. And particularly I remember, that though Oyl of Vitriol be one of the firiest liquors that is yet known, and does perform some of the Operations of fire it self, (as we shall elsewhere have occasion to shew) and will thaw Ice sooner than Spirit of Wine or any other liquor, as I have tried; yet having put about a pound or more, by our estimate, of choice rectifiedOyl
