C 265 ] 
XXXIX. ExtraSi oj Two Letters from Dr* 
Alfton, Bot. Prof, at Edinburgh, to Dr* 
Mortimer, Seer. R. S. The firjl dated 1 7 
March, 1 749 ; the fecotidy Auguft 9, 
I 75°* 
Readoa. 24, 4 PROPERTY of quick-lime, which 
jE\, I believe was not obferved before. In 
June 1743, for foipe experiments in vegetation, I in- 
fufed about 2 pounds of quick-lime in 24 pounds of 
water, refolving to change the lime, fo foon as it did 
not communicate its virtues to the water. I foon 
made ufe of the firft lime-water, and filled the veffel 
with frefh water. When that was exhaufted, I fill’d 
it up a third time ; and fo on for twenty or thirty 
times : for I had no reafon to change the lime for 
three years ; fo long it was good lime-water, gather’d 
crufts on its furface, turned fyrup of violets green, 
vegetable infufions yellow, tailed as at the firft. But 
at the end of the third, it gather’d no more crufts, 
was no more lime-water. 
The quick-lime, which I kept dry, fell foon into a 
powder ; it flood cover’d thefe three years (the vefiel 
with the lime-water in it was an inverted large bell— 
glafs, never cover’d) in the green-houfe. This pow- 
der I infufed in water, but it communicated no vir- 
tue to it whatever. This perhaps you will difficultly 
believe, but it is eafy to make the experiment. The 
calxvive , that I ufed, was made of the common lime- 
ftone. It is alfo a common obfervation of our farmers, 
that the effedt of lime on lands lafts only 3 years. 
L 1 Second 
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