ICE-HOUSES. 325 



ing a sufficient area of water. As forty cubic feet of ice 

 make a ton, a space ten by eight feet will yield one ton 

 of ice, if it is six inches thick. A pond, then, one hun- 

 dred by eighty feet, will yield one hundred tons, if of no 

 greater thickness than this. As ice is usually sold on 

 the pond for one dollar per ton, an ice pond will be found 

 an excellent investment in any dairy country. All that 

 is required is a clear running stream, with low banks 

 bordered by flat bottom land. A dam may be thrown 

 across the stream to back the water up to the higher 

 ground on each side. 



The dam must be built upon sound principles, or it 

 will not retain the water. The bottom must rest on 

 solid fresh ground, free from stone, grass, or decaying 



Fig. 60.— SECTION OF DAM AND POND. 



vegetable matter. The following method will be found 

 satisfactory. A trench three feet wide is dug out on the 

 line of the dam down to solid ground, clay, or hard pan. 

 Stakes are then driven in the middle of the trench reach- 

 ing as high as the top of the intended dam, and tongued 

 and grooved or otherwise tightly-fitted planks are nailed 

 to these stakes. Solid earth is then packed and puddled 

 in the trench on both sides of, the planks, and the dam 

 is then raised to the bight desired over this foundation 

 (figure 60). The slope of the dam should be such as 

 to make a six-foot dam nine feet wide at the bottom on 

 the inside and six feet wide on the outside, or fifteen feet 

 in all. This slojDe is needed to prevent leakage and the 

 washing down of the soil. The earth for the dam may 

 be dug out of the intended pond. 



