84 HATCH EXPERIMENT STATION. [Jan. 



from each side to the depth of 1 foot or more was placed 

 upon it. The cost of this appliance was about $20, though 

 Mr. C. R. Learned, who devised it, thinks that he could 

 make a duplicate of it for about $17. It took three days to 

 treat a house 300 feet long and 36 feet wide, and, from the 

 estimated cost of labor, fuel, etc., the treatment was made 

 at the rate of $5.92 per 1,000 cubic feet. This work was 

 done in the summer, when labor was probably more expen- 

 sive than it would be in winter. Mr. Learned informs me 

 that he expects better results the next time. 



A sterilizing machine used by Mr. Cartter is made of 2 

 inch galvanized-iron tubing, of 20 ply, with %6 or Vl mcn 

 holes, 1 inch apart each way. The headers are 2 to 3 

 feet long and 3 inches in diameter, and are made up of the 

 same material and perforated in like manner. Galvanized- 

 iron nipples are soldered on both sides of the headers, 8 

 inches apart. The ends of the 10-foot length pipes are 

 made to fit on to the nipples and also into one another, so 

 that any desired length or width of appliance can be ob- 

 tained (Fig. 1). This apparatus contains more perforations 

 to the linear foot than any we have seen, and for this reason, 

 and owing to the diameter of the tubing used, it is the most 

 effectual as a heater. We observed one test with this appa- 

 ratus in which 400 cubic feet of soil were treated at the rate 

 of $2 per 1,000 cubic feet. This includes the cost of labor 

 at 10 cents per hour, which was required to place the ap- 

 paratus in position and cover it with soil ready for use, 

 and replace the same when heated ; also the amount of fuel 

 burned during the treatment, together with the amount of 

 coal it required to bring the same amount of water in the 

 boiler to the same degree of temperature, and the steam to 

 the same pressure as before the treatment was started. 

 Whether this rate of sterilization by the use of this appa- 

 ratus is actually attained when applied on a large scale, we 

 have not learned. 



When soil can be sterilized at $2 per 1,000 cubic feet, or 

 even at $5, there is no longer any question concerning the 

 practical application of this method to rid greenhouses of 

 some of its worst enemies, which interfere! with the produc- 



