Reviews — Prof. G. Vicentini — Earthquakes. 277 



A. Monthiersi, A. citharella, A. Ludovici, A. Douvillei, A. Houdasi; 

 Scarabus Bonneti ; Ophicardelus sinuosus ; Marinula labrosa ; Sipho- 

 naria Tournoueri, S. granicosta. Gasteropoda (Opisthobranchiata) : 

 Actaon Octavii, A. Dumasi ; Crenilabium suturatum ; Scaphander 

 tenuistriatus ; Bullinella brachymorpha, B. Bideli ; PlicobuUa (subgen. 

 nov.) Dumasi; Cylichnella Bourdoti ; Amphisphyra subcylindrica ; 

 Bingicula Morleti. 



III. — Prof. G. Vicentini on Earthquake-Pulsations. 



(1) " Osservazioni e Proposte sullo studio dei Movimenti Micro- 

 si smici " : Atti della R. Accad. dei Fisiocritici (Siena), v, 1894. 



(2) " Microsisinografo a registrazione continua ; Cenno sui movi- 

 menti sisinicidei giorni 14 e 15 Aprile, 1895 " : Bullettino della Soc. 

 Veneto-Trentina di Scienze Naturali (Padova), vi, 1895, pp. 5-12. 



(3) "Microsismografo a registrazione continua " : Bollettino della 

 Soc. Sismologica Italians, i, 1895, pp. 66-72. 



(4) " Osservazioni sismiche " : Atti della R. Accad. dei Fisiocritici 

 (Siena), v, 1894. 



(5) "Movimenti sismici registrati dal microsismografo nella prima 

 meta del luglio 1894" : ibid. 



(6) " Intorno ad alcuni fatti risultanti da osservazioni micro- 

 sismiche " : Atti e Memorie della R. Accad. di Scienze, etc., in Padova, 

 xii, 1896, pp. 89-97. 



In the first three of these papers, Prof. Vicentini describes the 

 instrument with which his investigations have been made at Siena 

 and Padua ; the fourth and fifth contain an account of the records 

 at Siena from February 17 to July 14, 1894, and are accompanied 

 by copies of some of the more interesting diagrams ; the last and 

 most valuable of the series summarizes the conclusions at which he 

 has so far arrived. 



The microseismograph is a heavy pendulum, about 1^ metres (or 

 a little less than five feet) in length. The centre of the base of the 

 mass which forms the bob of the pendulum is connected with the 

 upper end of the short arm of a light vertical lever, so that every 

 movement of the mass is magnified by the lower end of the lever. 

 A further magnification is obtained by means of two horizontal levers 

 at right angles to one another, the shorter arms of which are con- 

 nected with the lowest point of the vertical lever. The other ends 

 of the horizontal levers consist of sharp points, which rest lightly on 

 a strip of smoked paper driven underneath them by clockwork. 

 When the pendulum is at rest, these points trace straight lines upon 

 the paper. When it is disturbed in any manner, the path of the 

 centre of the heavy mass is determined by combining the curves 

 traced by the two points. 



The cost of the paper on which the records are made being very 

 small, an unusually rapid movement can be allowed, and thus the 

 diagrams are to a great extent free from that confusion caused by 

 overlapping which can hardly be avoided when the more expensive 

 process of photographic registration is employed. 



The character of the diagrams is found to depend on the strength 



