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Description of the Apparatus or Signal-Post Jbr regulating 

 Chronometers. By R. Wauchope, Esq. Captain R. N. 

 With a Plate. Communicated by the Author. 



Mr Dear Sir, 



X HE enclosed drawing will more fully explain the nature of 

 the plan given in the last Number of your valuable Journal, for 

 ascertaining the rates of chronometers by an instantaneous sig- 

 nal. 



In addition to what was there stated, I have only to suggest, 

 that in a situation such as the Calton Hill, for instance, near 

 Edinburgh, where there is an Observatory without a regular 

 observer attached to it, it is not imperative that the true time 

 should be shewn every day ; but when a meridian observation 

 of the sun is taken, the flag may be hoisted at noon, which will 

 intimate that the ball will di'op at one o'clock, or any other time 

 which may be fixed upon. The flag should, as mentioned in 

 the accompanying description, be hauled down precisely one 

 minute before the true time is shewn by the ball. 



By this most simple contrivance, any gentleman belonging to 

 the Astronomical Institution, Avho knew the error of the Obser- 

 vatory clock, might, any day that was convenient, announce the 

 true time to the towns of Edinburgh and Leith, and to the 

 shipping in Lcilh Roads. 



At a foreign port, where a resident observer cannot be ob- 

 tained, a transit instrument may, nevertheless, be fixed in the 

 meridian of the place, and a flag-staff" for the instantaneous sig- 

 nal be erected, and placed under the charge of some careful 

 jierson, to be used by any man-of-war or merchant ship, having 

 time-keepers on board, touching there; as the observation by 

 the transit of the sun over the meridian, is both more accurate 

 and more easily obtained than by the present method in general 

 use, viz. by a sextant and artificial horizon. 



Should this plan for sliewing true time be universally adopt- 

 ed, which, from its simplicity, it bids fair to be, both by this 

 country and by France and America, there will then be no port 

 of any consequence into which a ship can enter, where an accu- 



JANU.MU — MAUCII 1830. T 



