Memoirs of the Kakioka Magnetic Observatory Vol.04 No.02, p.11, September, 1943
On the Mechanical Collector
Misaki, M.
Abstract
 In summer of 2601, two kinds of mechanical collectors designed by Mr. Y. Yokouti were installed at the observatory. Their constructions and some observed data are reported.
In the first type, the shielding plate is rotated over the two insulated plates which take the surface charge proportional to the existing earth's field when they are exposed. On the contrary, the insulated plate of the second type rotates under the fixed shielding which has two apertures. The former is shown in Fig. 1, and the latter in Fig. 7.