STEAMING THE SOIL 89 



fuel and labor, two sets of perforated pipes are needed. 

 Estimating 8 pipes to a bed and 30 ft. long, 240 ft. of 

 pipe will be required for one set, and two sets with cross- 

 head pipe will require about 500 ft. of pipe. Pipe such as 

 required, ij^ in. in diameter, can be bought as low as 2c. 

 per ft. from building and wrecking companies, while new 

 i]/2 in. pipe can be bought for 4c. per ft. Estimating the 

 pipe at 3c. per ft. for 500 ft., with connections, crosshead, 

 cost of drilhng holes, and fitting, at $6, the initial cost of 

 two perforated pipe systems will be on an average about 

 $20 or $10 for each one. 



The two sets of pipes are suggested in order to save 

 outlay for labor and fuel. It requires time to dig up 

 and reset a system of pipes, and this resetting of one 

 system may be done while the process of steaming is going 

 on in the other system; thus no labor is idle and steam 

 will not have to be kept up unnecessarily long. In fact, 

 the double system reduces fuel and labor by nearly 

 one-half that required where only one system of pipes 

 is used. 



In the inverted pan method the apparatus consists 

 of a galvanized iron pan, 6 in. deep and 6 ft. by 10 ft. in 

 size, which is inverted over the soil to be sterilized and the 

 steam admitted under pressure. The pan is supplied with 

 steam hose connections, has sharp edges, which are forced 

 into the soil on all sides to prevent the escape of steam, 

 and is fitted with handles for moving it from place to 

 place, the weight of the entire pan being not over 400 

 pounds. 



The soil is prepared as in the first mentioned method, 

 a few Potatoes being buried at a depth of a foot to gauge 

 the degree of heat obtained. A soil thermometer may 

 also be used if desired. The steam should be kept at as 



