You may remember, that the Spring before the last, I shew'd you a particular Account of a way, wherein by a certain substance obtain'd from _Sal Armoniack_, I could presently produce a considerable degree of _Cold_, and that with odd Circumstances, without the help of _Snow_, _Ice_, _Niter_ &c. But that Experiment being difficult and costly enough, and design'd to afford men _Information_, not _Accomodations_, I afterwards tryed, what some more cheap and facile mixtures of likely Bodies with _Sal Armoniack_ would do towards the Production of Cold, and afterwards I began to consider, whether to that purpose alone (for my first experiment was design'd to exhibite other _Phaenomena_ too) those mixtures might not without inconvenience be omitted: and I was much confirm'd in my conjecture, by an accident, which was casually related to me by a very Ingenious Physician of my acquaintance, but not to be repeated to you in few words, though he complain'd, he knew not what to make of it. Among the several ways, by which I have made infrigidating Mixtures with _Sal Armoniack_, the most simple and facile is this; Take one pound of powder'd _Sal Armoniack_ and about three Pints (or pounds) of Water, put the Salt into the Liquor, _either_ altogether, if your design be to produce an intense, though {257} but a short coldness; _or_ at two, three, or four several times, if you desire, that the produced coldness should rather last somewhat longer than be so great. Stirre the powder in the Liquor with a stick or whalebone (or some other thing that will not be injur'd by the fretting Brine, that will be made) to hasten the dissolution of the Salt; upon the quickness of which depends very much the intensity of the Cold, that will ensue upon this Experiment. For the clearing up whereof, I shall annex the following particulars. [Sidenote: * _In the History of Cold._]