304 Transactions of the American Institute. 



within a few hours after a heavy rain, and, as it comes from the con- 

 ductor with considerable fall and force, it agitates the whole body of 

 water, helping to keep it pure and sweet. In this corner apartment 

 is a block-tin inch pipe leading to the pump. If a quart of water is 

 pumped from this corner, another quart finds its way through the 

 pores of the brick to supply its place, and thus through the day, as 

 water is hourly being used or taken from this corner apartment, there 

 is a conetant circulation or movement of the water passing through 

 the brick to supply the consumption, thereby tending to free it from 

 all impurities. I have used this brick partition for a filter over five 

 years, and give it a decided preference. The water has always been 

 clear, and apparently pure, being made so in part by its almost con- 

 stant motion in connection with the filtering. The bricks appear to 

 be as sound to-day as when first laid." 



Mr. John L. Bridger, Tarboro, N. C, asks the following : In very 

 solid and firm clay, can the walls, other than partition, be constructed 

 without brick ? Can the external water be kept from the cistern 

 water by cement, or by cement and gravel laid upon solid clay walls ? 



The Chairman — I plastered cement directly upon the gravel and it 

 worked well till I left the place, some twelve years after. 



Professor Ii. C. Colton — This matter is one of much moment to 

 the people in the section where this gentleman lives. A great dea A 

 of the spring water there comes through marl, and hence contains 

 lime. I would further remark, Mr. Chairman, that the people of 

 that county (Edgecombe) are probably the best agriculturists in the 

 south. They do more work and use more manure to good purpose 

 than any other section of the south, and much of the credit for it is 

 due to this gentleman and his brother. They make heavy crops of 

 cotton on land where others seldom raise more than 150 or 200 pounds 

 of lint. The superiority of Edgecombe farming is notorious in that 

 section. Much of it is due to this very marl, which makes bad water, 

 but the farmers deserve the credit for using it. He can make his cis- 

 tern, as Chairman Ely says, by making good hydraulic cement and 

 gravel. Pure white sand is the best filter. My experience in Mis- 

 sissippi and elsewhere south leads me to advise that the first runnings 

 from the roofs be not run into the cistern, but off into the yard, or 

 thrown away in any other manner. After the water has run clear, then 

 turn it into the cistern. A good, cheap filter is a tight box half filled 

 with sand. Keep the cistern-top tight, and draw the water from it by 

 a pump. It will keep sweet a great length of time, but it is best to 

 keep a few clean fish in it, such as perch or trout. 



