[ I0 5 ] 
ment, was, that it was not furnilhed with a fufficient 
quantity of fixed air, the following mixture was 
made, which contains the lame proportion of earth 
as the former, but a lefs proportion of fixed air: 
4 ^ ounces of the above-mentioned water, containing 
fixed air, were diluted with 6 i. of rain water, and 
then mixed with 6 ounces of limewater. A pre- 
cipitate was immediately made on mixing, which 
could not be re-diffolved on fhaking. 
Experiment IX. 
I made fome experiments to find whether the un- 
neutralized earth could be precipitated from other 
London waters, by the addition of lime water, as well 
as from Rathbone-place water. It is neceffary for this 
purpofe, that the quantity of lime water Ihould be 
adjufted very exactly ; for, if it is too little, it does 
not precipitate all the unneutralized earth ; if it is 
too great, fome of the earth in the lime water re- 
mains fufpended. For this reafon, as I found it al- 
moft impoffible to adjuft the quantity with fufficient 
exactnefs, I added fuch a quantity of lime water, as 
I was well allured, was more than fufficient to pre- 
cipitate the whole of the unneutralized earth ; and 
when the precipitate was fubfided, decanted off the 
clear liquor, and expofed it to the open air, till all 
the lime remaining in the water was precipitated, by 
attracting fixed air from the atmofphere. The clear 
liquor was then decanted and evaporated, which is 
much the molt exact way I know of feeing whe- 
ther any unneutralized earth remains fufpended in the 
water. The refult of the experiments was as 
follows : 
Vol. LVII. 
P 
200 
