Ill 



as far as a 32lb gun. This 121b gun, with l^lbs of powder, at 8d.» 

 for say three signals a week, Monday, Wednesday, and Friday, will 

 amount to £7 16s. per annum. Now, in addition to this, it would be 

 necessary to adopt a similar signal at Launceston, which, without 

 any difficulty, could be switched by the telegraph from the report of 

 the Hobart Town gun. By this means the time would be kept 

 simultaneously from one end of the island to the other for £15 123. 

 per annum I may mention here that the difference of time between 

 Hobart Town and Launceston, by known longitude, is 55.847 seconds, 

 but the clocks frequently vary from ten to fifteen minutes, and some- 

 times more. The time occupied in switching the signal from Hobart 

 Town to Launceston is inappreciable, as the estimated speed of the 

 electric current, according to Wheatstone, is 286,000 miles per second ; 

 Walker makes it 18,000 miles per second, and Fizeau, 62,700, and 

 110,000, according to the material employed. 



If the government expect to carry out the proposed railways, and 

 other public works, a very large number of men will be required, 

 and it is quite clear that if something approaching to correct time is 

 not adopted, a few minutes loss for each man every meal will very 

 soon amount to a much more considerable sum than the cost of a 

 few time signals. 



The system which I have now partly attempted to describe well 

 illustrates the beneficial effects arising from the mutual co-operation 

 of several parties to carry out a common object ; and it is this joint 

 action alone which maintains a system by which a country may uncon- 

 sciously be benefited. I may tell you (says the Astronomer Royal) 

 my friend, Mr. W. De La Rue, estimates the amount annually saved 

 to his firm, by having exact time, and enforcing strict attendance on 

 his work people, at £800 per annum, besides some saving of gas and 

 coals, not taken into account. Think only, says Professor Airy, of 

 £300 per annum being thus saved in one establishment alone, and 

 then consider what would be the saving in London, if all establish- 

 ments of a similar magnitude could save by this system a like 

 amount. 



The Astronomer Royal says in conclusion, that he hopes to see 

 some day soon, an extension of the Greenwich system carried out in 

 the exhibition of hourly time signals at the Start Point, and that he has 

 prepared a complete scheme for the purpose ; the signal by day being 

 the drop of a ball or semaphore arm, and the signal by night a flash 

 of gunpowder. The value of such a system for ships would be very 

 great, since it would enable masters to obtain for their chronometers 

 seagoing rates, which is a thing of great importance 



i 



