8 



BULLETIN 956, U. S. DEPARTMENT OF AGRICULTUEE. 



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It will be seen, therefore, that the test can is firmly attached to the 

 cover of the retort by means of the brass fitting, and the can may be 

 placed in or removed from the retort in a very few seconds by simply 

 putting on or taking off the cover. Owing to the small size of the 

 retort, equilibrium at an}^ steam pressure desired may be attained in 



10 to 30 seconds. 

 The top of the mer- 

 cury column is al- 

 ways in sight, and 

 th e temperature a t 

 the center of the con- 

 tainer may be read 

 directly at any time. 

 Figure 1 shows the 

 arrangement of the 

 apparatus and the 

 position of the test 

 can in the retort. 



THE BRASS FITTING. 



The accompanying 

 illustrations (fig. 2) 

 show in detail the 

 structure of the spe- 

 cial fitting to which 

 the can is attached 

 for the test. Nu- 

 merous modifications 

 of this are possible, 

 to suit all needs. 

 The original form is 

 shown at A. The 

 threaded stem screws 

 into the cover of the 

 retort until the hex- 

 agonal shoulder 

 presses upon the 

 gasket and forms a 

 steam-tight joint with the retort cover. The threaded portion below 

 the shoulder screws into the hole of the ordinary maximum ther- 

 mometer test can in common use. With suitable gaskets air-tight 

 joints are made, and the can may be attached or removed as desired. 

 Cans of this type were used largely in these investigations. The 

 f-inch hole through which the thermometer is passed is reamed out 



srem/ /vr/9/f£r. 



Fig. 1. — Apparatus designed for making time-temperature 

 tests in canning food products, showing the position of 

 the test can in the retort and the arrangement of the 

 long-stemmed thermometer used in taking can tempera- 

 tures. 



