324 SEC. 10. ELECTRICITY. 



It consists of five parts : 



(1.) The float with chain and counter-weight which when acted on by the 

 rise or fall of the water impart their motion to the contact arrange- 

 ment. 



(2.) The contact arrangement which communicates the motion of the float 

 to the recording instrument by opening or closing the circuit. 



(3.) The recording instrument ; this shows the level of the water at all 

 times, the pointer being acted on by the motion to and fro of two 

 electro-magnets. 



(4.) The conducting wire. 



(5.) The battery. 



1695a. Model of Aerial Telegraph, by Chappe. 



Telegraphs Department, Paris. 



1695b. Model of Aerial Telegraph, by Monge. 



Telegraphs Department, Paris. 



1695c. Model of Aerial Telegraph, by Breguet and 

 Bettancourt. (This model belongs to the Conservatoire des Arts 

 et Metiers.) Telegraphs Department, Paris. 



1695d. Model of the First French Electric Telegraph, 



with two needles. Telegraphs Department, Paris. 



1695e. Electric Telegraph, by Morse, with latest improve- 

 ments. Telegraphs Department, Paris. 



1695f. Autographic Apparatus, by Mayer, constructed by 

 Mr. Hardy. Telegraphs Department, Paris. 



1695g. Quadruple Autographic Apparatus, by Mayer. 



Telegraphs Department, Paris. 



1696. Group of Apparatus, consisting of a clock move- 

 ment for showing the height of water ; an electric alarum for 

 indicating the heating of axle bearings by friction. 



C. $ E. Fein, Stuttgart. 



This is intended to show the heating of an axle in its bearings, and for 

 this purpose is placed in an opening in the cap piece, so that its lower end 

 touches the axle. As soon as the temperature rises, contact is made and a 

 bell rings. The metal of the bearings, plummer block, &c. serve instead of 

 return wires, so that only one insulated conductor is required. 



1697. Group of Apparatus, comprising an electric control 

 clock, with six locking signal studs. C. $ E. Fein, Stuttgart. 



This is for use in manufactories, public buildings, &c. The dial is a paper 

 disc, which is changed daily, and revolves once in 12 hours; it contains 

 as many rings as there are stations. By pressing down a knob at any of the 

 stations an electro-magnet inside the clock draws its anchor forward, and a 

 mark is made on the dial. As the dial is very large, minutes can be read 

 off easily. When a new dial is put on, the knob in the centre is to be turned 

 so as to set the clock to the right time. The clock will go for several days, 

 but it is better to wind it up daily. The signalling knobs can be kept locked 

 up, and may be opened by the watchman with a key which is common to the 

 whole apparatus. 



