

 140 ANNUAL OF SCIENTIFIC DISCOVERY. 



fiat copper wire, some non-conducting substance, as cotton, silk, or gutta- 

 percha, being interposed between the two metals. At each end of the ele- 

 ments short lengths of flat copper wire are made to project, and these are 

 soldered to the ends of the zinc plate of the adjacent element. Any metals 

 capable of inducing voltaic action may be used, and the inside strip may be 

 covered by the outer metal in a variety of ways. In one of the forms adopted, 

 rows of transverse slots are cut out of the enveloping metal. In another are 

 holes, like perforated window-blinds ; while in a third the outside metal is in 

 the form of wire-gauze, which last is said by the inventor to act very well. 

 The elements are soldered together in sets of ten or eleven each, and two or 

 more of these sets are hinged together to form a battery. At each end of the 

 battery is fixed a small socket one being the positive pole, and made of 

 gold ; the other the negative, and made of silver. These sockets project 

 through holes provided for them in the case, and it is to them that the con- 

 ductor cords are attached by a common clasp. These cords have a fine metal 

 wire twisted up with them, and covered by an external braiding of silk or 

 mohair. They terminate in small metal plates, which are provided with slots 

 at the back for the introduction of a tape to bind them to the body. The bat- 

 tery is excited by being slightly moistened by dilute acetic acid, and the 

 conductor-plates are wetted and applied at the parts between which it is 

 wished to pass an electric current. The battery, in its neat case, may be car- 

 ried in the pocket, or worn about the person in any convenient manner. 



APPARATUS FOR DISCHARGING ATMOSPHERIC ELECTRICITY FROM 



TELEGRAPH WIRES. 



An invention, recently patented in the United States by John N. Gamewell, 

 of England, relates to an apparatus for discharging into the earth all atmos- 

 pheric electricity with which the telegraph wires become surcharged when 

 the atmosphere is in a highly electrical state, thereby obviating all danger of 

 injury to the magnet or telegraph instrument, and enabling the telegraph to 

 be operated during the severest thunder storm. The theory on which this 

 instrument is constructed is based upon the established principle that atmos- 

 pheric electricity will leap from one conductor to another, but that a galvanic 

 current will not pass through the smallest space without a continuous con- 

 ductor. 



Mr. Gamewell provides an angular coil of wire, placed near the telegraph 

 instrument or receiving magnet. The wire composing the coil is either made 

 tapering, and diminishes from the size of the telegraph wire to a very small 

 diameter, or in lieu thereof, the elbows of the coil are made of a poorer con- 

 ducting metal than the other portions. This is for the purpose of causing the 

 atmospheric electricity, when it arrives at the elbows, to leap from them on to 

 some conducting points of better metal, which are placed almost in contact 

 with the elbows. The conducting points are all arranged on a metallic bar^ 

 and this is connected with the earth by a rod. The apparatus is placed be- 

 tween the end of the telegraph wire and the telegraph instrument, so that all 

 electrical currents, in approaching the instrument, must pass through the el- 



