Dept. Bull. 1136, U. S. Dept. of Agriculture PLATE 3 
ey 
TO START CLOCK 
MOVE LEVER GENTLY 
TO STOP AND RELEASE 
A RECORDING THERMOMETER 
Changes in pressure produced in the bulb (not illustrated) by changes in the temperature of the 
air surrounding it are transmitted through the tube a to the spiral pressure-sensitive element 6, 
which is made of flattened tubing. ‘The pressure changes cause the free end (the outer one) of the 
element 5 to move back and forth. This movement is transmitted through the link c to the arm d, 
which through its pen records the change on the chart e. The chart is rotated by means of the clock /. 
Seven-day charts are customary in kiln work, although one-day are also used. 
