318 SEC. 10. ELECTRICITY. 



1348a. Current-reversing Electrode. 



J. Teller, Munchen. 



This gives a more convenient change of current than the commutators so 

 far as electro-medical apparatus is concerned. 



1349. Double Reversing Key, used for cable testing. 



Elliott Brothers. 



1350. Thomson's Reversing Key, used in connexion with 

 the electrometer, for facilitating the measurement of the electro- 

 static capacity of a cable or condenser. Elliott Brothers. 



1351. Lambert's Key, constructed for charging ordischarging 

 cables and condensers. Elliott Brothers. 



1352. Spottiswoode's Rapid Break, for use with Intensity 

 Coils. Tisley and Spiller. 



By means of this "break the discharge in vacuum tubes can be regulated, 

 and the motion of the stratifications diminished or rendered stationary, as 

 required. See Proceedings Royal Society, June 10, 1875. 



1354. Forms of discharge on making and closing an induc- 

 tion current. Prof. Donders, Utrecht. 



The trial with the noematachograph to have the instant of stimulation 

 registered on the chronoscopic line by the current itself, led to the discovery : 



1. That the discharge can form a long series of sparks. 



2. That the electricity disappears more slowly when the spring rests on 



metal, more rapidly when it rests on a plate of mica, than in the form 

 of sparks making holes in the paper. (Compare Onderzoekingen 

 gedaan in het phys. labor. Ser. 2, T. III. 1870; and Wiedemann, Die 

 Lehre vom Galvanismus tmd Electroinagnetismus, 2 e Auflage, 1874, 

 B. II., s, 360.) 



1355. Drawings showing the patent system of lightning 

 conductors applied to buildings. J. W. Gray $ Son. 



1356. Model of mid-section of a Ship, showing the patent 

 system of lightning conductors applied to vessels in Her 

 Majesty's service, &c. J. W. Gray > Son. 



1357. Indestructible Solid Copper Tape Lightning 

 Conductors. Small and large sizes. Sanderson fy Proctor. 



This form of lightning conductor possesses the greatest conducting surface. 

 Hitherto it has been made in short lengths riveted together ; now it is made 

 in any length without joints, thereby offering less resistance to the free passage 

 of the electric current. 



1358. Copper Rope Lightning Conductors, improved. 

 The smallest and largest sizes. Sanderson fy Proctor. 



1359. ETew Lightning Conductor Apparatus. 



Prof. Carl Wenzel Zenger, Prague. 



