SCOURING LANDS OF CENTRAL SOMERSET. 
307 
drink such lias water imbibe with it a very large quantity of 
mineral and saline substances, which experience teaches 
disturb the regular functions of the digestive organs, and 
cause the cattle to scour. 
Composition of Spring Water from Ford Farm . 
An imperial gallon was found to contain— 
Organic matter , , 
Sulphate of lime 
Carbonate of lime 
Sulphate of magnesia . 
Chloride of sodium 
Sulphate of potash and soda . 
•56 
109-87 
26-55 
25 80 
6-65 
6-17 
175 '60 grains. 
On comparing the composition of this water with that of 
the Dunball Spring, a general similarity will be noticed. 
Both springs contain an abnormally large quantity of mineral 
and saline constituents which cannot fail seriously to affect 
the health of cattle that drink them. The spring at Ford 
Farm is not quite so rich in mineral matters as that from the 
Dunball cutting, but it nevertheless contains a larger pro¬ 
portion of such matters than many waters which, rising in 
the lias clays, are well known to possess aperient properties. 
The fact, therefore, that certain waters in the lias formation 
scour cattle, finds a full and satisfactory explanation in the 
peculiar composition of the two preceding springs. 
The saline mineral substances in these waters, of course, 
exist in the beds from which the springs rise, or else they 
would not be found in the water. The blue lias clay, there¬ 
fore, must be regarded as the primary source from which the 
scouring properties of the water arise. In this sense it is, 
after all, the land which causes the mischief. The large pro¬ 
portion of sulphates in the springs of the lias clay is worthy 
of notice, for it explains the peculiar and disagreeable smell 
which at times characterises these waters. This smell is 
due to sulphuretted hydrogen—a gas w 7 hich is generated 
w 7 hen sulphates are brought into contact with organic matters, 
free access of air being excluded at the same time. 
It has been asserted that the coldness of certain waters 
may be the reason why cattle who drink them scour. But 
this is not the case; the temperature, as such, has nothing 
whatever to do with the scouring properties of drinking 
water. It is perfectly true, how T ever, that the hard lias 
springs are invariably cold in summer in comparison with 
rain, ditch, or peat water. In winter, on the contrary, they 
are warmer than surface springs. This shows that the lias 
springs, which often issue from clay beds of considerable 
