PHYSICAL ann LITERARY. 381 
Havinc filtered the lime-waters of N° 2. 
and 3, into the fame bottle, befor I fufpected 
that any thing of the lime remained in them, 
it became impoffible to know, which of them 
afforded moft of the calcarious powder preci- 
pitated by the alcaline falt, or whether it did 
not proceed wholly from N°3.; in which 
cafe, fixteen ounces of it muf{t have contain- 
ed 17 gr. of the earthy part of the lime, and 
and N°2. only 12 gr. 
Since N°2. and 3. were not quite free of 
the lime, altho’ they had ftood expofed to 
the open air rg days, and had loft above 7 
‘by evaporation ; it follows, that the fureft 
way of knowing the quantity of calcarious 
earth, contained in lime-water, is to evapo- 
rate it, as Dr Langrifh did*: and, if it be 
objected to this, that all water affords fome 
earth, when evaporated; the quantity of 
this may be determined by experiment: tho’ 
in many waters, it may well be neglected, on 
account of its fmallnefs. 
Iv has been argued that quick-lime muft, 
after many repeated affufions of water, yield 
- as {trong lime water as at firft; becaufe, as 
long as there remains any virtue in the lime, 
the 
* Phyfical experiments on brutes. P. It. 
