I. ELECTRICAL MACHINES, ETC. 269 



1309. Spark Induction Machine, No. 1, with armature and 

 Geissler's tubes. Reiser and Schmidt, Berlin. 



1310. Spark Induction Machine, No. 2, with armature and 

 Geissler's tubes. Keiser and Schmidt, Berlin. 



1311. Spark Induction Machine, length of spark, six milli- 

 meters. Keiser and Schmidt, Berlin. 



1312. Spark Induction Apparatus, length of spark, one 

 centimeter. Keiser and Schmidt, Berlin. 



1313. Induction Apparatus, length of spark, 4- 5 centi- 

 meters. Keiser and Schmidt, Berlin. 



1314. Induction Apparatus, length of spark, 8 centimeters 



Keiser and Schmidt, Berlin. 



1315. Magnetic-induction Machine. 



Baur and Haebe, Stuttgart. 



1. This apparatus, containing several electro-magnets and a current 

 regulator, is furnished with double coils of wire, and may be used to set in 

 action electric apparatus of very various resistance and with very quick 

 interruption of current, e.g., Ruhmkorrf coils. In general, any experiments 

 may be made with it that are made with batteries of 1-6 Bunseu elements. 

 It is suitable, for medical purposes, galvanocaustics, &c., and, if a part of 

 the rotating electro-magnets be wound with fine wire, for production of a 

 constant current up to 60 Meidinger elements. 



e. MAGNETO-ELECTRIC MACHINES. 



1316. Ladd's Dynamo-Magneto-Electric Machine, with 

 two wires on one armature. William Ladd $ Co. 



Invented March 1867. (See Proceedings of the Royal Society, No. 91, 

 1867.) 



This was the first machine with two armatures, one being employed to excite 

 the electro- magnets and the other to produce an electric current, which may 

 be used for any purpose to which a battery is applicable. 



. 1316a. Ladd's Dynamo-Magneto-Electric Machine, 



with two wires on one armature. This machine will heat 15 

 inches of platinum wire. William Ladd $ Co. 



1317. The first Magneto-Electric Machine, with circular 

 magnets, 1866. William Ladd fy Co. 



1318. Magneto-Electric Machine, with circular magnets, 

 larger form, 1867. William Ladd $ Co. 



1319. Magneto-Electric Machine (direct current). 



James How $ Co. 



1320. Magneto-Electric Machine (Duchenne's form). 



James How fy Co. 



