110 



International Telegraph Company, by means of a *• Chronopher," 

 (Icsii^nccl and constructed l)y C. F. Varley. 



To arrive at the correct mean time for the Clreenwicli normal 

 clock, the error is found from the transit clock that has been pre- 

 viously rated by astronomical observations from certain clock stars, 

 the positions of which arc known with great accuracy ; one of these 

 stars being observed by aid of the chronograph, an apparatus that 

 has been in use at Greenwich since the year l.So4, and part of which 

 consists of a revolving cylinder attached to a clock, on which is fixed 

 a paper which is punctured at the time a star transits over each web 

 of the telescope. This record is then extracted from the chronograph, 

 and the mean of all the webs, or punctures taken ; this mean when 

 corrected for instrumental errors and personal equations, is the 

 difference between the R.A. of the star and the sideral time clock ; 

 a comparison is then made (by the coincidences of beats) between 

 the mean time clock, and sideral clock, from which the correct mean 

 time is ascertained, as at the Cantonal Observatory at Neuchatel to 

 one tenth of a second. 



At Newcastle a clock which is kept adjusted to Greenwich time 

 makes automaically the proper connections for allowing an electric 

 current to arrive at Newcastle to act on relays which transmit 

 currents to discharge the Tyne time gims, one of which is placed 

 on the old Xorman Keep at Xewcastle, the other at North Shields. 

 The gun at Newcastle is a 12 pounder gun, that at North Shields is a 

 24 pounder. Very general reference is made to these guns, not only 

 by the public generally, but also by manufacturers and ship-building 

 companies, for regulating their works, and not less important are the 

 facilities they give for the rating of chronometers. 



The first Glasgow time-gun was supplemented by a second one in 

 St. Vincent's Place on the 29th of October, and these two by a third 

 at the Broomielaw, on the 10th of November, while a fourth gun 

 was added to the system at Greenock on the 21st of November, all 

 four being simultaneously fired through the agency of the electric 

 current from the Observatory. 



At Madras, measures have been taken by the astronomer, Mr. 

 Norman Pogson, with funds supplied to him by the Governor-in- 

 Council, to convert no less than five guns, which are daily fired in 

 and about that city, by counec^ng them electrically with the normal 

 mean time clock of his observatory. Mr. Pogson says that " the 

 smoke by day, and the flash by night of a time-gun, are far better 

 and more conspicuous signals than any time ball." 



I have collected and put together the foregoing facts in order to 

 show that the system of time signals is becoming very generally 

 adopted, and much ingenuity, expense and trouble has been brought 

 to bear for economising time in well-regulated communities. 



In the discussion which arose on this subject at the monthly 

 meeting for ]\Iay last, the object itself was approved of, the only 

 objection raised was the expense, the estimated amount of which 

 was in a great measure fallacious. The 32lb. guns fired on the first 

 Thursday in the month at 4 p.m. were heard at Richmond, Sorell, 

 and Prosser's Plains. It is however the opinion of the Military 

 Officers that a 12 pound brass gun, with Ij or Ipb of powder such 

 Jis the one used at Newcastle, would, be heard, if not quite, nearly 



