Oct. 10, 1881] 



♦ KNOWLEDGE ♦ 



299 



Fi?. 1. — New French Stem-Wheel Gunboat. 



( c^UJ^DLea 



FiL'. 2.— Plan of the Vessel. 



not the slightest evidence of a shock having been imparted, 

 we, or rather doctors, are still toUilly at sea in explaining 

 the disaster. 



There is, however, sufficient evidence to enable us to 

 determine what does and what does not constitute a danger. 

 Where there is a low electro-motive force, say, of 100 volts 

 (as in machines for supplying incandescent lamps), 

 however low the resistance of the dynamo, even if it be 

 " decimal nought, nought, nothing," do harm can accrue 

 because of the high resistance offered by the human body. 

 Consequently it matters little, so far as personal safety is 

 concerned, what the connections are or where they are 

 made. With machines of high electro-motive force, how- 

 ever, the case is different. Bare wires should rarely if 

 ever be permitted. The Paris accident above quoted clearly 

 establishes thi;'. Further, a complete metallic circuit should 

 be insisted on, that is to say, the circuit should never be 

 completed through the earth, otherwise danger attends 

 every operation. 



With proper care in planing and fitting, supplemented 

 by average intelligence on the part of attendants or users, 

 there is not more — nay, rather there is even less — danger 

 to be apprehended from the adoption of the electric light 

 than from gas. Nothing is here said about the many other 

 advantages pertaining to illumination by electricity, my 

 object being rather to point out what dangers really exist, 

 and how easily they may be counteracted. 



NEW STERN- WHEEL GUNBOATS. 



OUR engraving gives a general view of one of the ne^v 

 stern-wheel gunboats that the Minister of the Navy 

 and Colonies has lately built for service on the rivers Ton- 

 kin and Gaboon. These vessels, five in number, were con- 

 structed by the Societe des Anciens Etablissements Clara- 

 pede. They bear the names of Henry Riviera, Carreau, 

 Gamier, Berthe de Villers, and Pionnier. As they are de- 

 signed to run upon Chinese and African rivers, whose 

 waters are often very low, their maximum draught is 

 70 m., and their minimum speed is nine knots. They are 

 provided with a 250 h.p. motor. 



Each vessel consists of a flat-bottomed float of Bessemer 

 or Siemens-Martin steel, of the first quality, thoroughly 

 zinced. It is provided with three false keels, and the 

 deck is surrounded with a rail. Upon the deck, and under 

 a roofing are established cabins for the commander and 

 crew. Above the roofing there is a platform arranged in 

 such a way as to receive all the vessel's armament. The 

 latter consists of two 90 mm. guns, one fore and one aft, 

 and four Hotchkiss revolving guns. There are six places 

 provided on the platform for three of these revolving guns, 

 the fourth being stationed at the top of a hollow steel mast 

 located amidship. The interior of the float is divided 

 into twenty-eight compartments that contain the various 

 store-rooms and magazines, as shown in the plan in Fig. 2. 



