傾斜計の製作

Abstract

At the Calamity Research Institute in Oosaka, a tiltometer was constructed which is of new form taken after that of Dr. Wadati's long-period seismograph and its whole body is made of metal.This instrument was designed with following intensions: (1) portable by its small size and weight, (2) easily adjustable for every body, (3) scarcely influenced by temperature change, and (4) able to change photographic paper without any troublesome treatment.It is adopted Zellner's style to hang the horizontal pendulum with thin tungsten wires, and the frame has a symmetrical construction so as to avoid an irregular deformation by the influence of temperature change. The pendulum has a device of magnetic damping. The camera for recording the ground tilting consists of a hollow cube made of brass and has a rotating cylinder enveloped with a sheet of bromide paper in it. This camera can be separable from the other parts, so that the observation is able to be carried on even in a bright room, though the change of paper has to be done in a dark room. The pendulum can be easily brought to the state having a period of more than 30 sec. The experiments were done to obtain the relations between φ and y (inclination of the earth's surface and the displacement of a light spot), S and T0 (sensibility and the proper period), i and T0 (inclined angle of the pendulum axis and ibid.) etc. and all show satisfactory results for the present purpose of routine observation. These results may be seen in Fig. 4, 5, 6 and Table 1, 2.