. DESCRIPTION OF A LARUM FOR A WATCH. 22?^ 



tvatch is put to the larum, was parallel to the horizon ; its 

 distance from the centre of motion was one eighth and 

 three fourths of an inch. I hunj^ a slender thread upon the 

 pin, with ten grains troy weight tied to it^ which moved the 

 crew. 



This larum maybe seta week before-hand, if the watch May be set as 

 would go as long, by increasing the number of threads of hand as the 

 the screw. watch will go. 



When a watch is made to wind up the contrary way, it is Left hand 

 necessary only to take out the pin in the axis of the detent, ^^^^ * 

 and turn the lever the other side up, and then it will drop off 

 at the other end of the screw to disengage the laru'^. 



By taking notice at what hour you wind up your ^'atch, Number of 

 and by winding it up again at twenty-four hours, you v, ill ^£^i^J^(^^qq^^ 

 ascertain how many hours are contained in one turn of the 

 fusee, the most common are four, five^ six, hours for each , 

 turn. I have divided the common index into 120, which 

 does for three concentric circles. That next the centre is 

 for a watch fusee of four hours a turn ; the next five, and the 

 last six. While the hand of the larum passes over one of the 

 "jdi visions, it will be equal to two minutes to the four hours 

 «ircle, two and a half to the five hours, and three minutes to 

 the si!t hours circle, all shown by the same hand. 



Before a v/atch is put to the larum, it must be fitted with A particular 

 n key that will not drop off when the watch is turned with ^^^ i^ecess^ry. 

 the key-hole downward, something like that which I have 

 sent ; then hang up the watch by the pendant to the holder, 

 which may be turned while the key end on the watch is 

 opposite to the axis of the screw, and the face of the 

 watch parallel to the plate. Then turn the sliding pieces 

 any way, as may suit the watch in that situation, and 

 screw it fast. 



Supposing the watch is four hours in making a turn of the Method of set- 

 fusee, turn back the hand of the larum while one of the pins ^i"§ ^^« 

 touches the pin in thew^atch key, and if the han^ is not at 

 top, turn it back till it is. If the larum is required to go off 

 4n foui* hours, lift the lever into the first turn of the screw ; if 

 in fi^e hours, turn back the larum hand one hour; if in six 

 horn's, two back; if in seven hours, three back ; and if in 



eight 



