SOIL STERILIZATION 99 



gallons, but the weaker solutions do not seem to be 

 effective against many other diseases. 



Application. There is universal agreement that one 

 gallon of the solution should be applied to each cubic 

 foot of soil in order to thoroughly saturate every particle. 

 It may be applied by means of watering cans, sprayers, 

 barrels with hose attachments, overhead system of water- 

 ing, special devices and through the regular water pipes 

 of the house, and at different times, if the soil does not 

 absorb the solution promptly. 



The watering-can method is slow and tedious and 

 should not be used except in small houses. Sometimes 

 barrels are supported on trellises 5 or 6 feet above ground 

 and bibs inserted for hose attachment. A frame 10 feet 

 square may be shifted from place to place, and this will 

 mark each area which should receive a barrel of the 

 solution. In soils that do not absorb water rapidly it 

 will be necessary to return to the same areas two or three 

 times in order to apply the full amount and to avoid 

 puddling the surface. 



The pipes used in the overhead system of watering 

 have been employed sometimes, but the lack of uniform 

 distribution is an objection to this plan. 



B. H. Thorne, in the 1909 Report of the Vegetable 

 Growers' Association of America, gives the following 

 description of the formalin tank which is shown in 

 Fig. 33: 



"In order to get the right proportions, run clear water through 

 the tank into a barrel of known capacity and time it, then run water 

 through the formalin tank under the same pressure as the water, 

 regulating it by the valve at S until the formalin tank runs one pint 

 of formalin to 25 gallons of water. The water tank should be at 

 least ten times the capacity of the formalin tank in order to furnish 

 air to take the place of the formalin used. 



"The apparatus should be pumped full of air before it is used. 

 A bicycle pump attached at A will do it nicely. The mixture will 



