2 On Lime. 
vegetation, and that it diminishes the fertility of the soil. 
The distinguishing characteristics of these two varieties 
of lime, mentioned by Mr. Tennant, it would seem, . 
can only be discovered either by analysing, (which pro- 
cess farmers are generally ignorant of ;) or by making 
experiments by applying it to the soil. It is said that 
magnesian lime when used in too great quantities ren- 
ders the soil less fertile, and wherever a heap of it has 
been left on one spot, vegetation will be prevented for 
many years; while of the other sort of lime, a large 
quantity is never to be found injurious; and that the 
spots which are entirely covered with it, become re- 
markably fertile, instead of being rendered barren. 
From the above statement it would appear that by far 
the greatest proportion of all the limes used either in 
this country or in Europe are of the magnesian kind, 
or in other words must contain a certain proportion of 
magnesia. For my own part I have never seen pure 
calcarious lime, unless that made from calcined shells 
may be denominated such; though I must own I am 
not chemist enough to be able to discover the magne- 
sian lime, except by its effects upon the soil, as above 
described by Mr. Tennant, and Dr. Darwin. The dis- 
tinctions which some farmers make, of hot and mild 
lime, Mr. Tennant believes to mean magnesian and cal- 
carious lime. And the Doctor says he is informed that 
the magnesian lime is preferred in architecture, and is 
said to go further in making mortar, &c. If this is the 
case I think it will be admitted that all the lime used in 
the United States, either for building or manure, is of 
the hot or magnesian kind ;* as it is well known that the 
lime of this country is generally stronger and of course 
