SCIENTIFIC NEWS. 135 



the enormous expence which would attend it, and is un- Mr. Day's 

 neceflfary when we reflect that the ufual number of men em- watchman's re- 

 ployed, will be fufficient, if any mode can be adopted of fixing 

 and afcertaining their vigilance. The initrument called the 

 zvatchman's noctuary, or labourer's regulator, offers a mode for 

 this purpofe. By one of fuch being placed at each end of a 

 watchman's round, it will be afcertained how the man con- 

 tinued his movements through the night, to a nicety of ten • 

 minutes at any period of the watch — and the flighteft irregu- 

 larity or omiflion will be vifible the next morning to the in- 

 fpector or conftable, whofe office it (hall be to open the machine. 

 The teft of regular and well-fuftained vigilance is given by 

 the Watchman's dropping a token as he paffes, every half 

 hour, quarter, or half quarter, into a receiver or cell ; each 

 half hour or quarter prefenting it's own cell to receive the 

 fame, and each cell, like time itfelf, irrecoverable when 

 paffed. No trick or fraud on the watchman's part can 

 counteract the movement of the horizontal wheel formed of 

 thefe cells, and completing a revolution once in twelve hours. 

 He has no command over it, and each cell (as it moves under 

 the receiver) will be a kind of fpeaking witnefs of his diligence 

 and fidelity in going his rounds, anfwering the next morning 

 to the exact periods he either was or ought to have been 

 there. 



By this means the calls of the Watchmen, which were only 

 militated for the purpofe of his giving notice of being on his 

 duty, will be fuperfeded ; and a coniiderable expence of animal 

 exertion will be faved to the individual, which might better 

 be converted into that of going his rounds twice, where he 

 now only goes once. Warnings to the nightly thief of timely 

 attack or retreat will likewife be taken away, and if inftead 

 of an open the watchman was to carry a dark lanthorn, the 

 robber would have no fecurity whatever in calculating the 

 moment of his depredation, and might be detected in the very 

 outfet of his attack, as the flighteft found would alarm the 

 watchman walking in filence, and not drowning diftant noife 

 by that of his own voice. 



Of the objections to this new mode of ameliorating the 

 watching of cities, the only one feems to the expence of the 

 time pieces, — and confidering the number which the larger 

 parishes will have occafion for, this expence will be im- 

 portant ; 



