MEMOIRS 
OF THE 
AGRICULTURAL SOCIETY 
OF 
PHILADELPHIA. 
Some hints concerning Lime, occasioned by reading Dar- 
win’s Phytologia. By John Lang. 
‘Read August 9th, 1808. 
WE have for some time past heard much talk about 
two varieties of lime, the one useful or favourable to 
the growth of vegetables, when used as a manure; the 
other hurtful or pernicious, and therefore not to be 
used for that purpose; the first is termed calcarious, 
the other magnesian lime. 
The first notice we have of this magnesian lime is 
from a communication of Mr. Tennant, published in 
the London Philosophical Transactions. 
This is doubtless a subject of great importance to 
farmers, and in my opinion deserves to be more fully 
investigated. If all lime which contains magnesia is. 
only useless as a manure, it must be of great importance 
to our farmers to be informed how they may be able to 
distinguish this from the calcarious lime; but much 
more so if it isas Mr. Tennant says, destructive to 
VOL. Il. A 
