Oct. 5, 1882] 



NATURE 



She is 25 feet in length, and about 5 feet in the beam, 

 drawing about 2 feet of water, and fitted with a 22-inch 

 propeller screw. On board were stowed away under the 

 flooring and ceats, fore and aft, 45 mysterious boxes, each 



555 



a cube of about 10 inches in dimensions. These boxes 

 were nothing else than electric accumulators of the latest 

 type as devised bv Messrs. Sellon and Volckmar, being a 

 modification of the well-known Plants accumulator. Fully 



Fin. 2 — The E'eciric Launch. 



charged with electricity by wires leading from the 

 dynamos or generators in the works, they were calculated 

 to supply power for six hours at the rate of four horse- 

 power. These storage cells were placed in electrical con- 

 nection with two Siemens' dynamos of the size known as 

 D 3, furnished with proper reversing-gear and regulators, 

 to serve as engines to drive the screw propeller. Either 

 or both of these motors could be " switched " into circuit 

 at will. In charge of the electric engines was Mr. Gustave 

 Phillipart, jun., who has been associated with Mr. Volck- 

 mar in the fitting up of the electric launch. Mr. Volckmar 

 himself and an engineer completed, with the writer, the 

 quartette who made the trial trip. After a few minutes' 

 run down the river and a trial of the powers of the boat, 

 to go forward, slacken, or go astern at will, her head was 

 turned Citywards, and we sped — I cannot say steamed — 

 silently along the southern shore, running about eight 

 knots an hour against the tide. At 4.37 London Bridge 

 was reached, where the head of the launch was put about, 

 while a long line of onlookers from the parapets surveyed 

 the strange craft that without steam or visible power — 

 without even a visible steersman— made its way against 

 wind and tide. Slipping down the ebb the wharf at 

 Millwall was gained at 5.1, thus in 24 minutes terminating 

 the trial trip of the Electricity. For the benefit of electri- 

 cians I may add that the total electromotive force of the 

 accumulators was 96 volts, and that during the whole of 

 the long run the current through each machine was 

 steadily maintained at 24 amperes. Calculations show 

 that this corresponds to an expenditure of electric energy 

 at the rate of 3 ru horse-power. 



Fig. 2 gives a general view of the electric launch afloat. 

 The arrangements of the driving machinery are shown 

 in Fig. 3, which is a section of the boat, taken amidships. 

 The accumulators, B B, are stowed as low as possible, 

 and form an admirable ballast. The two Siemens' 

 dynamos are connected by belts with an overhead coun- 

 tershaft, and arranged with a friction-clutch, by means of 

 which one dynamo can be thrown in or out of gear at 



will. From the countei shaft a third belt passes down to 

 a pulley on the axis of the screw. Each of the engines 

 is provided with two pairs of brushes at the commutators, 



Fig. 3. — Section of electric launch showing driving machinery. 



one pair having a lead forward, the other backward, 

 enabling the motion to be reversed by raising or lowering 

 one or other pair of brushes. Cf the practical success 



