12 A MANUAL OF 



the sudden heating of the pipes, so near the 

 furnace, is quite sure to crack them. Common 

 drain-tile may be safely used at a little distance 

 from the fire, and is cheaper than terra-cotta 

 ware. The pipes, of whatever construction, 

 should be at least -six inches in inside diameter. 

 Good terra-cotta pipes of this size can be pur- 

 chased in our vicinity at about twenty-five 

 cents per running foot, and in this item con- 

 sists the main cost of this kind of a bed over 

 a common manure-bed. Of fuel, we have the 

 advantage over many sections of country, in 

 being near enough the anthracite-coal region 

 to enable us to procure a supply at very small 

 cost. We have, however, found one ton of 

 chestnut coal amply sufficient to run a bed 

 seventy-five feet in length for six weeks, and 

 there are few sections of country in which the 

 cost of coal is so great as to compare with the 

 value of a sufficient quantity of horse manure, 

 capable of producing the same amount of heat. 

 When using manure for a bed of this size, we 

 found that, to produce a good and lasting heat, 

 at least one wagon-load for each 3 by 6 sash 

 was required. This would cost here at least $2 

 per load, which, for the twenty-five sashes re- 

 quired to cover the seventy-five feet of bed, 



