THE HYDROGEOLOGY OF THE PLYMOUTH DISTRICT. 121 
Dr. Letheby's Analysis, dated 17th December, 1863, of Plymouth 
water as supplied, is as follows : 
PLYMOUTH WATER AS SUPPLIED TO THE INHABITANTS. 
Grains. 
Carbonate of Lime and Magnesia 1.05 
Sulphate of Lime 0.91 
Alkaline Chloride 1.22 
Alkaline Nitrate 0.41 
Silicia and Alumina 0.51 
Organic matter 0.40 
Total Grains in Imperial Gallon 4. 50 
