488 
recorded as attacking the cotton plants. The pests recorded arc 
however records of enemies all over the world and a very large pro- 
portion are naturally not met with in the German colonies. The 
literature of cotton is very large but this little work of 145 pages is 
a useful addition. 
In their African Colonies the Germans have a fine field for the 
extension of one of the most important products of the world, and 
they seem to be making great progress in the cultivation of cotton. — 
Ed. 
PURIFICATION OF BRACKISH WATER ON 
ESTATES. 
M. Kelway Bamber sends us the following letter on the treatment 
(if brackish water from the saline muds and peaty soils, which not 
rarely occur on our lowland country near the sea. This article will, 
we think, be read with interest by those who have estates on the plain 
country along the coasts where the water is often foul. 
“Re brackish water from Selangor muds, I had some sent over 
of the worst kind to make some experiments regarding its purification 
for drinking and manufacturing purposes. I enclose the analysis. 
The water was sour, brackish, muddy, and with a strong smell of 
decomposing organic and sulphur compounds. 
Lime water produced an immediate curdy precipitate which 
settled clear in a few minutes, but the water still had some smell. 
Alum solution caused a similar precipitate even more rapidly 
and the water cleared at lonce, but the smell was intensified and the 
water was still very acid. 
Permanganate of Potash also caused a bulky precipitate and if 
sufficient was added the smell in 24 hours practically disappeared, 
but this alone would be too expensive. 
I then found that a mixture of lime water, Alum and Perman- 
ganate of Potash, gave a clear water with little or no smell and quite 
capable of being used for rubber manufacture or for drinking, the 
cost being only about 2 3 cents per 1000 gallons. 
The method to adopt should be to dig settling tanks in one of 
the main drains passing near the factory site. These should be about 
50' long and 14' wide by 6' deep and can be dug along the drain at 
intervals of 50' or so. Two thirds full they would each hold 17,500 
gallons and they would require 
12 lbs. Quicklime stirred up in cold water 
34 lbs. Alum. 
V2 lb. Permanganate of Potash. 
