36 



at the angles. If an earthquake take place this ball and rod 

 fall into one of the eight angles, and so mark the general direc- 

 tion of the motion. At the other end is a pendulum with a 

 brass bob, suspended by wire from a brass support, with its 

 point within a little copper bowl which is used to record any 

 vertical movement of the earth. In the centre is a clock whose 

 pendulum is held by a detent, connected with a pair of electro- 

 magnets, until freed by the passage of an electric current. The 

 circuit is closed and the pendulum at liberty to swing as soon 

 as any movement causes either .the wire pendulum or the ball 

 and rod to come in contact with the metal near them. Thus the 

 time of the earthquake is recorded by the starting of the clock. 

 A Leclanche battery and an electric bell to be placed in circuit to 

 call attention to the earthquake are provided with the instrument. 



103. Seismochronograph, or apparatus for determining 

 the exact time of an earthquake. 



Designed by Prof, von Lasaulx, Royal University, 



E. 236. 1877. Breslau. 



This is similar in principle to the last, but is only part of 

 the whole. It consists of a plate in the centre of which stands 

 a rod working in a hollow vertical cylinder, on the top of 

 which is placed a ball. If by an earthquake the ball be 

 displaced it falls into one of the surrounding cups, the 

 particular one showing the direction of the shock, and at the 

 same time the rod rises and sets loose a wire spring, which causes 

 a neighbouring clock to stop, thus indicating the time of the 

 'shock. 



104r. Photographs and drawings of seismic apparatus 

 used at the Vesuvian and Meteorological Observatory, 

 Naples. 



1877. Given ~by Prof. Luigi Palmieri. 



1. Portable seismograph by Palmieri, with a printed 

 description. 



2. Stationary seismograph made by order of the Hydrographic 

 Department of the English Admiralty, by Prof. Palmieri. 



3. Stationary seismograph made for the Vesuvian Observatory. 



105. Photograph of an early seismograph. By Niccolo 

 Cacciatore. 



1877. Given by the Royal Observatory o/ Palermo. 



A circular receiver perforated on the side by eight holes, 

 placed in the direction of the four cardinal points and of the 

 intermediate points. This is placed on a perfectly horizontal 

 plane, and filled with mercury up to the level of the holes, 

 which will therefore spill by running through them on the 

 least oscillation, and in the direction of the oscillation. A 



