[ 479 3 
The feveral folations of common Salty if accu- 
rately repeated, would fhew in what proportion 
the gravities of fluids increafe, upon the addition 
of Salt: and that Sea-Water does not contain one 
twenty-fourth part of Salt. 
I have omitted in this table the three animal 
"fluids, Milk, Serum of Blood, and Urine, as the 
fame may be feen before in the 8 th table, that of 
animal parts ; but it may be noted in general that 
the fpecific gravity of all thefe fluids is nearly the 
fame as that of Sea Water. 
There are in Dr. Freind’s table feveral decoctions 
of Plants, which I have inferted, altho J they are 
not I think of much ufe, nor greatly to be de- 
pended upon. Several of them are lighter than 
common Water, in contradiction to Dr. Juriris ob- 
fervation, that Vegetable Farts are all heavier than 
Water: But it is probable thefe Experiments were 
made before the 'Decoffions were reduced to the 
temper of Common Water. 
What is meant by the Aqua cotta of Dr. Freind 
in his table, I cannot imagine > not having any idea 
of fuch a change by boiling or otherwife, as can 
deprive common water of a full fourth part of its 
weight. 
Since the denflty of the Air is as the force by 
which it is comprefled, it follows that the weight 
of any portion of Air muft vary in the fame pro- 
portion with the weight of the whole Atmofphere : 
which in our climate is not lefs than one tenth of 
the whole weight, allowing the Barometer to vary 
from 28 to 31 Inches. 
R r r 
Again, 
