cooling of Water below its freezing Point. 1 43 
As chemical combinations all depend upon attractions be- 
tween the fubftances which unite, it is not difficult to conceive, 
that a particle of fait, an acid, or the like, may attraCt a particle 
of water in fuch a manner as (hall oppofeor diminish its attrac- 
tion for the other particles of water. Hence the polarity may 
be fo much weakened, as not to bear the fame proportion to the 
refitting power of the latent heat, till this alfo is diminished 
by a greater degree of cold, which conttitutes the new freez- 
ing point. But when, by increafing the cold, all the powers 
are reduced to a fimilar ttate of equilibrium, exaCt ly the fame 
phenomena take place as belong to the natural freezing point 
of the water. 
To afiift the conception, I have here reafoned upon the par- 
ticles of water as folid, and of a determinate (nape. But it 
feems mott probable, that the particles of matter in general 
are nothing more than centres to certain attractive and repul- 
five powers; on which hypothefis it may beunderttood, that if 
two or more of thefe central points are brought much within 
the limits of their refpeCtive attractions and repullions, thefe 
powers will no longer be equal at equal diftances from their 
common centre. Now fuch a combination of central points 
may be considered as one particle of any particular matter ; 
and the unequal diftances from the common centre at which 
the attractions and repulfions are equal will define what may 
be called the Shape of that particle. And if, at equal diftances, 
the attraction or repulfion is much greater at one point than at 
another, that will constitute a polarity. 
The greateft cold I have been able to make water acquire 
without freezing, is near 12 degrees of Fahrenheit’s Scale 
below its common freezing point. Some diftilled water was* 
boiled about a quarter of an hour in a tin cup, and placed in 
the . 
7 . 
