306 
SCOURING LANDS OF CENTRAL SOMERSET. 
In the face of these well-authenticated facts we cannot 
reasonably doubt that certain waters in the lias formation 
possess scouring properties. 
I was anxious, therefore, to ascertain whether lias-waters 
have an abnormal constitution, and to this end I myself 
collected some of the water from the lias-cutting at Dunball, 
and from the spring at Ford Farm, to which reference is 
made in Mr. Poole's note. Both were submitted to careful 
analysis, which furnished the following results: 
Composition of Water from the Lias-cutting at JJunball. 
An imperial gallon evaporated to dryness gave— 
202'02 grains of solid residue (dried at 300° F.) 
This residue contained— 
Organic matters 
•96 
Mineral saline matters 
. 20P64 
Consisting of— 
Lime ..... 
. 60-48 
Magnesia .... 
. 12-20 
Potash .... 
2 39 
Soda ..... 
. 12-29 
Sulphuric acid 
. 91-40 
Chlorind .... 
. 11-20 
Carbonic acid and loss 
. 10-10 
These constituents, united together in 
the compounds 
which in all probability existed in the water, 
give the follow- 
ing results: 
An imperial gallon of water from lias cutting at Dunball contains— 
Organic matter 
•96 
Sulphate of lime 
. 104-77 
Carbouate of lime 
. 30-91 
Sulphate of magnesia (Epsom salt) 
. 36-60 
Sulphate of soda (Glauber salt) 
5-93 
Sulphate of potash 
4-42 
Chloride of sodium (common salt) 
. 18-45 
202-02 
It will be seen that the water contains an enormous quan¬ 
tity of mineral mater, and in this mineral matter a consider¬ 
able proportion of Epsom salt, Glauber salt, and other 
aperient saline substances. It is an extremely hard water, 
and essentially differs in composition from ordinary hard 
drinking waters ; for in very hard waters we seldom find 
more than 40 to 50 grains of solid matter in the imperial 
gallon, or only one fourth of the quantity contained in the 
lias water. In good drinking water, of average degree of 
hardness, the amount of mineral matters varies from 20 to 
30 grains in the gallon, and soft waters contain only from 
5 to 10 grains in the gallon. 
During the dry and hot summer months, cattle which 
