io8 



SCIENCE OF SUCCESSFUL THRESHING 



to straighten, as a hose will do when under pressure. The 

 free end of the Bourdon tube is connected to the hand 



or pointer by means of a seg- 

 ment lever and pinion so that 

 the pointer, which is on the same 

 shaft as the pinion, revolves, in- 

 dicating on the dial the pressure 

 on the inside of the tube, which 

 is the same as that in the boiler. 

 The black dial with white fig- 

 ures and graduations is pre- 



FIG. 33- INTERIOR OF GAGE. ferre( J by many Qn account Q f 



the ease with which the figures are seen at night. 



The Steam-Gage Siphon. In order 

 to prevent the temper of the tube of 

 the gage from being drawn by the 

 hot steam, a device, consisting of a bulb 

 containing two small tubes is placed be- 

 tween the gage and the boiler. The 

 sectional view of this "siphon," as it 

 is called, shows a small tube extending 

 upward to the top of the chamber, and 

 another depending downward towards 

 the bottom. The entering steam will 

 be deflected to the bottom of the cham- 

 ber where it is condensed, thus effect- 

 FIG. 34. SECTION uallv preventing any live steam from 

 entering the gage. 



OF SIPHON. 



