o?§) 
2. The VtoYAtion of the Cold, produc’d by this Experiment , depends upon 
feveral Circumflances - as Firft> upon the Seafon of the year, and prefent tem- 
perature of the Air • For, in Summer and Hot weather the Cold will fooner 
decay and expire. Secondly , upon the Quantity of the Salt and Water : For, 
if both thefe be great, the effed will be as well more Ming, as more confide- 
rab !e.T hkdly Jor 'ought I yet know, we may here add the Goodnefs & Fitnefe 
of the particular parcel ofSalt,that is imploy’d : for, though it be hard to dif* 
cern beforehand, which will be the more, and which the lefs proper • yet fome 
trials have tempted me to fufpedl, that there may be a considerable difparity^ 
as to their firnefs to produce Cold, betwixt parcels of Salt, that are without 
fcruplelook’tupon as Sal Armoniack-.Of which difference it were not perhaps 
very difficult to affign probable reafons from the Nature of the Ingredients 
of this compound Concrete, and the waies of preparing it. But the Duration of 
the Cold may be conceived to depend alfo, Fourthly, upon the Way of putting 
in the Salt int® the Water For, if you caftit in all at once,the Water wil foon- 
er acquire an intenfe degree of Coldnefs- but it will alfo the fooner return to 
its former temper ^ Whereas , ifyou defire but an inferiour degree of that 
Quality, but that may laft !o.nger(which wil ufually be the mod convenient for 
the Cooling of Drinks,) then you may put in the Salt by little and little. Jor, 
keepings long Weather- glafs for a good while in our impregnated Mixture l 
ofcen puipofeiy try'd, that, when the tinned liquor fubfided but f!owly,or was 
at a {land, by putting in, from time totime,2 or 3, fpoonfuls of frefh Salt,and. 
Birring the Water to quicken the DiffoIntion,the Spirit of Wine would begin 
again to defcend,.if it were at a Band or riling, or fubfide much more fwifitly 
than it did before. And if you would lengthen the Experiment, it may not be 
amifs,that part of the Sal Armoniack be but grofly beaten,that it may be the 
longer in diffolving,and confequently in Cooling the Water.Whilfl there are 
dewy drops produced on the outfideofthe Veffel , Tis a fign , that the Cold 
within continues pretty flrong • for,when it ceafes, thefe drops efpecially in 
warm weather, will by degrees vanifh.But a furtr way of meafuring the dura»- 
tion of the Cold, is, by removing from time to time the Seal’d Weather- glafs 
©ut of the Saline Mixture into the fame commonWater,with part of which it 
was made. And though it be not eafie to determin any thing particularly about 
ibis matten- yet it may fomewhat ailifl you in your Eflimates, to be informed. 
That I have in the Spring by a good Weather, gfafs found a fenfible adventi- 
tious Cold, made by a pound of Sal Armcaiack at the utmofl,to lafl about 2. 
or 3, hours. 
3. To cool Drinks with this Mixture, you may put them in thin Gaffes, the 
thinner the better ; which ( their orifices being flopp’d , and.flill kept above 
the Mixture) may be mov’d to and fro in it , and then be immediately pour’d:: 
out to be drunktThoLigh,when the GIafs,I imployed,wasconveniently fhap’d^ 
as, like a Sugar- loaf, or with a long Neck, I found it not amifs to drink it out 
of that, without pouiing it into any other ; which can fcarce be done without 
leffning the Goolnefs. The refrigeration, if the Glafs- vial! be conveniences 
quickly perform'd t And if one have a mind to cool his hands, he may: readily 
do it by applying them to the outfideof the Veflel, that contains the refrige- 
sating Mixture • by, whofe heip^ieces ofChryflaljOr Bullets for the cooling of 
