422 0)1 the Chemical Composition of Phosphatic Minerals 
river deposit. The land phosphate deposit is lighter coloured 
and softer than the river phosphate. It is altogether dug by 
hand with spade, pick, and shovel, a portion being taken from 
the sand that overlies it ; but the main yield is from the clay 
in which it is imbedded, and which is the best land rock. But 
the clay, we are told, is hard to separate, requiring much care 
and time to remove it by washing ; while^ that found in the 
sand readily yields to the action of water, and is less expensive 
to clean. The land phosphate is private property, and mostly 
owned by the parties who work it ; or it is rented by them, or 
worked in shares, or for a subsidy, and they pay no tax or royalty 
to the State for removing the rock. 
The first importations of Charleston or South Carolina land 
phosphate were not washed properly, and generally contained 
a larger percentage of sand than more recent cargoes brought to 
England. 
The following analyses of two samples of Charleston land 
phosphate made in my laboratory show its composition in detail. 
Detailed Composition of Two Samples op South Carolina 
Land Phosphate. 
No. 1. 
No. 2. 
2-78 
5-38 
1-79 
24-15 
24-66 
35-78 
37-18 
•57 
-76 
3-99 
4-15 
3-20 
4-90 
2-91 
4-08 
1-84 
not determined. 
Alkaline chlorides (common salt) 
2-15 
3-50 
2-05 
Insoluble siliceous matter (fine sand) . . 
19-13 
.15-05 
100-00 
100-00 
* Equal to tribasic phosphate of lime . . 
52-72 
53-83 
6-61 
9-27 
Charleston land phosphate is readily ground to a fine powder. 
It contains less carbonate of lime than good Cambridge cppro- 
lites, but rather more oxide of iron and alumina, and siliceous 
matter. The proportion of phosphate of lime in Charleston 
land phosphate seldom exceeds 55 per cent., and frequently it 
is less. When treated with sulphuric acid it makes a good 
superphosphate, and on the whole is preferable to, and rather 
