[ 47 8 ] 
“ diftant from one another. I found the difference 
between their fpccific gravities far lefs than almoft 
any body would expert. And if I be not much 
<£ deceived by my memory (which I muft have 
recourfe to, becaule I have not by me the notes 
<c I took of thole trials) the difference between 
waters, where one would expcft a notable difpa- 
riry, was but about the thoufandth part (and 
fometimes perchance very far lefs) of the weight 
“ of either. Nor did I find any difference con- 
tc ftderable in reference to our queftion, between 
“ the weight of divers waters of different kinds, as 
ec fpring-water, river- water, rain-water, and fnow- 
ic water $ though this laft was fomewhat lighter 
<c than any of the reff. And having had the curio - 
l( fity to procure fome water brought into England , 
if I much mifremember not, from the river 
“ Ganges itfelf ; I found it very little, if at all, 
“ lighter than fome of our common waters." 
The heaviefi: fluid we are acquainted with, next 
to Mercury , is Oyl of Vitriol , or water impregnated 
with the Vitriolic Acid in the higheft degree we 
can obtain it, being almofl double the weight of 
Water. 
The next is probably the Jaturated folution of 
the fix d Salt of V egetahles ; being a ponderous 
Salt, and diffolving freely in Water. 
The next to this is Spirit of Nitre. Spirit of 
Salt is lighter, and inferior in weight to the fiatu - 
rated folution of Salt itfelf. 
It is obfervable, that marine or common Salt 
and Nitre differ little in gravity, contrary to the 
nature of their Spirits. 
The 
