f 
( $5^ ) 
they have undergone, are loaded with many Fiery Parrt- 
cles which they hold, as it were in Prifon, in their Pores. 
Thefe Igneous Particles regain their Liberty by the Diffo- 
lution of the Sahne Particles. And in the fame time that 
thefe SzVcs ought to flacken the Motion of the Aqueous 
Particles, and cool it, the Igneous Particles being very 
aQ:ive, do augment the Agitation of the Watry particles 
till they make it very hot. 
I obferve next, that S^l Armoniac cools the Water where- 
^psIiA^mmL^^^ more than any other Salt. Its Cold e- 
even to Fretz^ quals that of Water which is ready to Freeze. And it 
'""^ happened one time, that in Diffolving a good quantity of 
this Salt in Water, fome Drops which fell on the outfide 
of the Viol in which I made the DilTolution did Freeze, 
and the Straw upon which the Viol ftood, being wet, was 
faftned to the Glafs Veffel, for fome time, by the Ice. This 
fell out fince the Summer, at a time when the Weather 
wis warm. 
I have many times fince tryed the fameExperiment,in dif- 
ferent ways,but without ever being able to produce thelce. 
Chance had apparently made me meet in this Experiment, 
not only a very exaft proportion between the Salt and the 
Water, bul^alfb a Temperature in the Water befides, which 
I fuppofe neceffary : becaufe the Diflblution being quick, 
the Goldnefs muft alfo be more fuddcn and great : and this 
33 that Degree of Temperature to which I could never af- 
terwards attain. 
lltnJ/'^' The great Coldnefs of the Diflblution of Sal Armoniac 
proceeds not from any difficulty which it has to be DiC- 
folv'd.fince it diflblves fooner than any other. And Sea- Salt, 
whofe Diflblution is difficult and very flow^ is that which 
does leaft cool its Diflblver. On the contrary, it feems 
that the facility and readinefs with which it Diflblves, 
may be the Caufe of this great Cold, in this manner. 
Sal Armoniac^ as every body knows, is a Compofition 
of Sea- Salt and Salt of Urine, the one very eafie, the other 
very 
