96 VEGETABLE FORCING 
inch header with six 1%4-inch outlets or laterals, placed 17 
inches apart, the laterals being 45 feet in length and per- 
forated with %-inch holes 10 inches apart. The header 
is placed crosswise of the bed to be sterilized, with the lat- 
erals running lengthwise. The pipes are buried to a depth 
of about 6 inches and the whole bed is then covered with 
a heavy canvas. The header is connected with the heat- - 
ing system at the center, giving three lines on each side. 
The Irondequoit grower referred to has also found 
ordinary 2-inch corrugated galvanized conductor pipe 
highly satisfactory. The pipes are light, easily forced 
together and they cool very quickly so that shifts may be 
made without discomfort. The perforations may be made 
with a ten-penny nail. It is desirable to turn the pipes 
with the perforations down, or to cover them with 
burlap to keep dirt out of the holes. The perforated pipes 
are simply buried in the ground beds under 6 or 7 inches 
of soil, and the bed is covered with heavy canvas to retain 
the heat. Ina very large range at Ashtabula, Ohio, eight 
gangs of pipe are used to keep quite a large force of men 
busy shoveling soil and shifting the pipes. A 300 horse- 
power engine is used in this establishment. 
Perforated pegs (Figs. 31 and 32) are used successfully 
in some sections. This is sometimes called the “steam 
rake” or the “steam harrow” method. These devices 
may be made of any convenient size and dimensions. 
The feed lines and arms are composed of a series of re- 
ducing nipples with T’s located so that the pegs will be 
about 8 inches apart, giving the appearance of a harrow. 
The arms of the feed lines may start with 34-inch pipe, 
the second joint '%4-inch and the third 34-inch. The 
Y-inch pegs are flattened at one end into the form of a 
wedge with a 3-16-inch perforation at the lower end for 
the escape of steam. A heavy 1-inch hose connects with 
the steam pipe that leads to the boiler. The sterilizer is 
forced into the ground and covered with canvas which 
