1908.] 



PUBLIC DOCUMENT — No. 33. 



39 



Table shoiving the Relative Heating Efficiency of Tubes of Various 

 Diameters, Sizes, aiid Numbers of Perforations. 



A comparison of one-inch and two-inch iron pipes, each 

 containing four rows, giving a total of forty-four perfora- 

 tions, three sixteenths of an inch in diameter, gave as a 

 heating capacity for two-inch pipe five minutes, and for one- 

 inch pipe eleven minutes ; or, in other words, it requires six 

 minutes longer for the one-inch pipe to heat the same mass 

 of soil than the two-inch pipe. An average of four experi- 

 ments gave for the two-inch pipe nine minutes and for the 

 one-inch pipe seventeen minutes, or nearly the same ratio. 



Two tests were made with one and one-half inch pipe, 

 smiilar in every way to those just described. Since this 

 pipe was mislaid, further experiments with it were discarded. 

 It may be stated, however, that the results obtained by the 

 use of this pipe were better than those with the one-inch, 

 although not so good as those obtained by the use of the 

 two-inch. 



A comparison of the three perforated tin and galvanized 

 u'on tubes (c, d and e) showed little variation in heating 

 capacity. The colander tin tubes, however, had a great 

 many perforations, representing a much larger area for steam 

 to escape. Notwithstanding this, it was not superior to 

 tube d, which was a section of Cartter's sterilizing apparatus. 

 The experiment with tile [f) was, as might have been ex- 

 pected, less satisfactory as a heater than any of the others 

 except the one-inch pipe. The lower end of the tile was 

 not closed, hence practically all the heat which escaped did 



