DESCRIPTION OF A TELEGRAPH* USED IN SWEDEN. ] Q$ 



In the firfl it is propofed to place a lamp behind each (hut- Firft plan. 

 ter at fuch a diftance as not to obflruct the movements, and 

 rather above the axis. In this method, by doling the fliutters 

 according to the plan indicated above, the lamps correfpond- 

 ing to the fhutters which are railed will difappear, and thofe 

 "which remain vifible will form a fignal the reverfe of that in- 

 tended, the value of which will be found on the right fide of 

 the table of cyphers defcribed before; hence the day fignal 

 will be before the fignification, and the night fignal after it. 

 But as this plan was found to be inconvenient in practice, or at 

 great difiances the following was fubflituted for it, a, b, c, d, Second plan. 

 (Fig. 3.) is a tin lanthorn having only two openings e, to 

 permit the pafiage of the light ; placed on oppofite fides, and co- 

 vered with talc or mufcovy glafs. Between thefe two openings 

 a good lamp is fituated fo as to give light in both directions. 

 g,f, k is a quadrant of tin adapted to each fide of the lanthorn, 

 and moveable on its axis h, in fuch a manner, that by means 

 of a firing attached to the arm 4 it may be raifed before the 

 openings of the lanthorn, but falls again by its own weight 

 when the firing is let go. Ten of thefe lamps are to be fixed 

 on a frame in a fimilar manner to the ten fhutters ufed by day, 

 the firings depending from each are united at the foot of the 

 machine, according to the fame principles and the fame com- 

 binations as in the day telegraph ; but as the weight and fric- 

 tion to be overcome is much lefs, this machine may be worked 

 at all times with the hands alone. One advantage which this 

 eftablifhment poflefles over the day telegraph is, that it does 

 not require to be placed above the horizon, it is even better 

 to be below it. Befides, in every point of view it is more 

 eafily worked and is much fuperior in utility to the telegraph. 



It is known that the fiars rrfay be feen in the middle of the probable vlfibi- 

 day from the bottom of a deep well ; it remains to be proved, Jj ty ,° f thg lamp8 

 if, by a fimilar effect the lamps can be feen in the day-time 

 with the aflifiance of very long tubes : fhould this be practica- 

 ble it will be highly advantageous in many refpe6te, particu- 

 larly in requiring only one eflablifhment for both purpofes. 

 By means of the equatorial telefcopes of Short or Ramfden, 

 the flars may be obferved at noon even clofe to the fun, hence 

 it is probable that if all foreign light is excluded, the lamps 

 will be vifible on a dark ground. Telefcopes which magnify 

 the mofl will be preferable, becaufe they darken the field of 



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