314 Mr. Tennant on different Sorts of Lime , &c. 
2.5 grains of spar; so that, 12.5 grains of spar required the same 
quantity of acid as 5.5 grains of magnesia. 
The magnesia used was very pure, and made red hot imme- 
diately before it was weighed. 
Substances examined. 
Quantity of 
spar which 
the acid, re- 
quired to 
take up the 
magnesia, 
would have 
dissolved. 
Quantity of 
magnesia. 
Quantity of 
lime. 
Iron 
and 
clay. 
Mixture of 5.5 grains of mag- 
nesia and 14 grains of cal- 
careous spar - 
12-5 
5-5 
7.8 
O 
25 grains of Breedon lime- 
stone, previously powdered 
5-071 
7-929 
.0 
25 grains from part of the 
same powder 
11.56 
5.082 
7-913 
2 
25 grains of Dolomite from 
Rome - 
12.2 
537 
7-73 
.1 
Dolomite from 
Iona - 
10.1 
4-4 
7.8 
j Imolu- 
1.0 1 ble sub- 
1 stance. 
Vesuvian Dolo- 
mite - 
10.38 
4-5<>5 
8-575 
.06 
A second experiment, from 
part of the same Vesuvian 
Dolomite - 
10.03 
4.411 
8.849 
.06 
25 grains of magnesian lime- 
stone from Wans worth, near 
Doncaster - 
12-75 
5.61 
7-34 
•2 5 
Thorpe arch - 
10.95 
4.84 
7.8 
.6 
Matlock 
12.5 
5-5 
7.388 
• 3 i 
York minster - 
11. 
4.84 
8.26 
.1 
Worksop 
11.6 
5-104 
7-49 6 
.6 
Sherburn - 
11.5 
5.08 
7-56 - 
-56 
— Westminster-hall 
10.1 
4-44 
8-37 
•4. 
