488 



recorded as attacking the cotton plants. The pests recorded are 

 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 

 of 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 23 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. 



Vi lb. Permanganate of Potash. 



