\\'II.I.IAM S1EM1-..\S, J'.R.S. 241 



portion of it. In this respect the electric light has every advan- 

 tage, for, by placing an electric lamp in focus to produce a 

 permanent spectrum, series of plants can be placed in different 

 portions of it, and the various results noted for any required 

 period. 



ON THE APPLICATION OF THE DYNAMO-ELECTRIC CURHKXT TO 

 LOCOMOTION. 



I have frequently before this taken occasion to refer to the 

 electric transmission of mechanical energy, and it is not my 

 intention to revert to this subject generally, but to confine myself 

 to an application for the propulsion of carriages along a railway, 

 which has recently been carried into effect by my brother, Dr. 

 Werner Siemens. 



On the occasion of a local exhibition held in Berlin a year ago, 

 a narrow gauge railway was laid down in a circle 900 yards long. 

 Upon this railway a train of 3 or 4 carriages was placed, and 

 upon the first carriage a medium-sized dynamo-electric machine so 

 fixed and connected with the axle of one pair of wheels as to give 

 motion to the same. The two rails, being laid upon wooden 

 sleepers, were sufficiently insulated to serve for electric conductors. 

 Between the two rails a bar of iron was fixed on wooden supports, 

 through which the current was conveyed to the train by means of 

 metallic brushes fixed to the driving carriage, while the return 

 circuit was completed through the rails themselves. At the 

 station the centre bar and two rails were connected electrically 

 with the poles of a dynamo-electric machine similar in every way 

 to the machine on the carriage, and which received motion from 

 one of the engines on the ground. (A diagram was exhibited and 

 explained, showing the arrangement, Dr. Siemens saying that he 

 was indebted to Mr. Shoolbred for it, who had prepared it for his 

 own purposes.) 



Between twenty and thirty persons could be accommodated on 

 the carriages composing this train, the conductor riding on the first 

 carnage, to which the form of a small locomotive engine has been 

 given. Instead of the steam valve used in the latter, this engine 

 is fitted with a commutator, by moving which the stopping, start- 

 ing, and reversing of the engine can be effected. 



VOL. II. K 



