100 VEGETABLE FORCING 
be as thoroughly done as in ordinary spraying. Be sure to have the 
outlet at the faucet end from the formalin entrance at S.” 
Mr. Thorne also gives in the same report the following 
description of a formalin mixer, making it possible to 
apply the solution through the regular water pipes: 
“The formalin mixer is made of two ordinary kitchen range 
tanks, one above and at one side of the other. The upper one holds 
the formalin and the lower one is the mixer. The tops of both are 
connected by a small pipe with a valve in it. This pipe is to equalize 
the pressure in both tanks by the passage of air back and forth. 
“The formalin tank has a glass water gauge at the bottom to show 
when the formalin gets too low, and the lower tank a gauge at the 
top to show when the water gets too high. From the bottom of the 
formalin tank a %4-inch pipe goes down to meet the pipe from the 
waterworks running into the bottom of the lower tank. Connect- 
ing the end of the %-inch pipe with the water-works pipe are a 
needle valve to regulate the flow of formalin, and another glass 
gauge to show that the formalin is running properly. 
“The formalin and water are mixed in the lower part of the lower 
tank by the moving water coming in continuously and the mixture 
runs out about one-third of the way up back into the water-works 
system. The apparatus is connected to the regular watering system 
through a by-pass. 
“In order to get the right proportions of formalin and water, run 
50 gallons of water through the apparatus and time it, and then 
regulate the needle valve to run out two pounds in the same time. 
An air-pump is needed to force air into the upper tank to force 
back the water in the lower tank when it gets too full. With this 
apparatus one man can apply the mixture as fast as the water runs.” 
It is also important to spray walks, benches, flats and 
tools with formalin. 
After sterilizing with formalin, planting should be 
deferred 10 days to two weeks because the plants will be 
injured if set too soon. 
Cost.—So many factors enter into the expense of steril- 
izing with formalin that it is difficult to give definite cost 
figures. When a mixer was used, Thorne claimed that 
the solution and its application cost about two-fifths of a 
