5i6 



NATURE 



[February i6, 191 i 



be produced; rock-yielding or JTsfortion of this char- 

 acter seems to have been measured in California 

 before the earthquake of 1906, which ruined San 

 Francisco and other towns. 



With properly equipped observatories on two sides 

 of the Straits of Messina, the existence or non- 

 -existence of such brady-seismical movements might 

 be demonstrated and limits be recognised which pre- 

 ceded a crash, Kovislegethy has suggested other 

 lines dependent upon the hysteresis of rock masses, 

 along which we might conduct investigation which 



The extent i)f this damage is shown in the accom- 

 panying figur. s. If it is only on account of the unique 

 position of thi:> observatory I feel certain that it is th(; 

 wish of all seismologists to see it restored and re- 

 equipped to exttnd its useful work. J. Milne. 



The Messina Observatory before and after the Earthquake of December 28, 1908, 



may possibly lead to the prediction of disaster. The 

 <iividing line between Calabria and Sicily is a theatre 

 of hypogenic activity, and is a place above all others 

 in Europe to be watched and studied carefully. As a 

 site on which to make investigations respecting cer- 

 tain changes which are taking place beneath our feet 

 it is of importance not only to Italy but to the world. 

 We see from a paper we have recently received that 

 the observatory at Messina in 1908 suffered severely, 

 the disaster being chiefly due to the fall of a tower. 



NO. 2Tf5, VOL. 85] 



SYNCHRONISATION OF CLOCKS. 

 TOURING the past two years a committee consist- 

 ^-^ ing of the following members of the British 

 Science Guild, Sir Hugh T-U, Bart., Hon. Sir John 

 Cockburn, K.C.M.G. (chairman) 

 Sir Norman Lockyer, K.C.B., 

 F.R.S., Major O'Meara, R.E.. 

 C.M.G. (representing H.M. Post- 

 master-General), Sir Alexander 

 Pedler, F.R.S., Dr. F. Molhvo 

 Perkin, Prof. J. Perry, F.R.S., Sir 

 William Ramsay, K.C.B. , F.R.S., 

 and Mr. St. John Winne, has been 

 engaged upon the consideration of 

 a problem which has often been re- 

 ferred to in the Press, both lay and 

 technical; that is, the question as 

 to how best may be achieved a 

 systematic observance of absolute 

 Greenwich mean time. 



The problem is not altogether one 

 affording opportunities for easy 

 solution, for, as stated in the re- 

 cently published second annual 

 report of the committee, it is 

 apparently beyond the power of 

 human ingenuity to produce two 

 clocks which will go together for 

 one week. Nor is the problem a 

 new one. In past years there have 

 been many endeavours to utilise the 

 services of electricity for the correc- 

 tion of clocks, so that a number of 

 such may be uniform in their indi- 

 cations. Some time about 1840 

 Alexander Bain devised an elec- 

 trically-driven pendulum, the prin- 

 ciple of which was adopted by M' 

 R. L. Jones, of Chester, to cau- 

 the pendulums of a group of clocks 

 to beat in sympathy with a regu- 

 lator, a system of synchronisation 

 which met with some degree of 

 success, but which was very limited 

 in scope. Since that date the 

 problem has been investigated by 

 many with varying degrees of 

 success. 



Greenwich mean time has been 

 for many years, and is yet, the 

 standard time for Great Britain and 

 Ireland, and the facilities afforded 

 bv the network of wires under the 

 control of the Post Office authorities 

 have been made use of for the dis* 

 tribution of standard time to those 

 to whom the possession of means 

 for ascertaining at any moment 

 exact Greenwich mean time is a sine qua non. The 

 distribution over the wires has hitherto resolved itsel 

 into the transmission from Greenwich Observatory-^ 

 where the standard mean time solar clock is corrected 

 dailv about 9 a.m. to accord with the results of the 

 preceding nocturnal stellar observations— of an elec- 

 trical signal to the Central Telegraph Office in 

 London, whence it is radiated over the telegraph wires 

 to offices in distant towns, and thence over direct 

 circuits to the subscribers who require the intelligence. 



