[ i83 ] 
Therefore the fupporting of fait in water is not 
owing to its fuperficies being encreafed. 
A lump of fait, though laid at reft at the bottom 
of a veffel of water, will diflblve therein, and its 
parts move every way till equally diffufed in the waterj 
therefore there is a mutual attradtion between water 
and fait. Every particle of water affumes as many 
of fait as can adhere to it j when more is added, it 
precipitates, and will not remain fufpended. 
Water, in the fame manner, will dilTolve in air,, 
every particle of air affuming one or more particles 
of water j when too much is added, it precipitates 
in rain. 
But there not being the fame contiguity between . 
the particles of air as of water, the folution of wa- 
ter in air is not carried on without a motion of the ' 
air, fo as to caufe a frefh acceffion of dry particles. 
Part of a fluid, having more of what it diflblves, . 
will communicate to other parts that have lefs. 
Thus very fait water coming in contadt with frefh, 
communicates its faltnefs till all is equal, and the, 
fooner if there is a little motion of the water. 
Even earth will diflblve, or mix with air. A , 
flroke of a horfe’s hoof on the ground in a hot 
dufty road, will raife a cloud of duft, that lhall, if 
there be a light breeze, expand every way till perhaps 
near as big as a cemmon houfe. Tis not bv me- 
chanical motion communicated to the particles of dull 
by the hoof, that they fly fo far, nor by the wind 
that they fpread fo wide. But the air near the ground, 
more heated by the hot duff Ifruck into it, is rariiied 
and rifes,^ and in riling mixes with the cooler air, and 
communicates of its duff to it, and it is at length fo 
diffufed i 
