1580 
5.1 Several experiments were conducted in which a Speedomax recorder 
was used to record the signal appearing across Ry) Ry at the 6SN7 
outpute (The recorder was made available through the cooperation of 
Mr. A- Bunker's meteorological group.) The Speedomax has ample sensitivity 
and stability for this purpose, and the results were very promising. 
‘Calibrations could be carried out rapidly and conveniently, with pressure 
signals and standard voltage signals being rapidly and continuously 
recorded on the moving paper» The record can be conveniently read and 
the results computed after the paper strip is removed from the recorder. 
One man operation is possible. 
The response time of the recorder is roughly the same as that of the 
Sensitive Research University model microammeters which have usually 
been used in this worke The error due to pyroelectric effect (which is 
greater the longer the response time) would therefore not be any more 
serious with the recorder than with previous devices.e It is therefore 
suggested that the most efficient and convenient calibration technique 
would be to use the electrometer and cathode follower stages of Figure 
19 to feed a Speedomax or Brown recorder as described above. 
Results of calibrations with the Speedomax are shown in Table IV 
and are found to agree well with the values obtained by CTC and by 
means of microcoulometer LH. 
In the preliminary experiments, it was not possible to connect the 
electrometer ground and the Speedomax. This led to some difficulty 
with pick-up when the operator touched the pressure chamber-e The pick- 
up was made negligible by careful isolation of the grounds and in- 
sulation of the operator. In a permanent set-up, suitable modifications 
could probably be introduced to eliminate the grounding difficulties. 
