PLATE IX 



Fig. I. — Four automatic balances in operation at Akron, Colo., June 19, 1912, with 

 the front of the box containing the mechanism open. The recording device is shown 

 just beyond the first box. A separate recorder is used for each instrument. 



Fig. 2. — Automatic balances, Akron, Colo., July 24, 1912; boxes closed and record- 

 ers covered. Except when being adjusted, this is the condition in which the appa- 

 ratus is maintained. 



