272 SCIENTIFIC RECREATIONS. 



his electric tramway. This was an improvement upon the first Berlin tram- 

 way, for in it the horses frequently received shocks which they resented. In 

 the later application the current comes from the generator by metal rods 

 carried above the heads of the passengers alongside the line. Little rollers 

 upon these are united with an electric machine in the tram-car. The current 

 is sent along the wires, and reconverted into mechanical energy in the second 

 machine, turns the wheels of the cars. In this way, as the car proceeds, the 

 rollers overhead or alongside the track are kept moving by the car, and the 

 connection is never broken. 



But this is a digression. The electric light as applied to lighthouses 

 was also exhibited, and any reader desirous to obtain full information upon 

 the subject of lights and lighthouses will find it in a very pleasantly-written 

 work by Mr. Thomas Stevenson, in which the various systems of lighting by 

 electricity and otherwise are fully recounted, the conclusion being in favour 

 of electricity, which is employed and has been used for years in France and 

 in some English beacons. If its penetrative power can be finally established,. 

 for some authorities maintain that the electric is more easily absorbed 

 by fog than other light, there is no doubt about its being universally 

 adopted. 



It is very interesting to watch the uses to which the electric light is 

 being put. The latest experiment has been made by an Austrian, Doctor 

 Mikerliez. Almost incredible as it may seem, the interior of the human 

 stomach can now be illuminated by means of a wonderful little instrument 

 called the Gastroscope, which is said to be actually in use and to have been 

 favourably reported upon by the medical faculty of Vienna. There is at the 

 end of a jointed flexible tube (which can be passed down the gullet) a 

 miniature lamp, far more marvellous and mysterious than that of Aladdin, 

 in which a strip of platinum is fixed and connected with fine wires conduct- 

 ing the electricity from a small battery. When contact is made, and the 

 " light turned on," the cavernous interior of the stomach is lit up. Still more 

 extraordinary is the fact that the tube can be made to revolve, and the light 

 reflected from the walls of the stomach and directed to the eye of the 

 observer. There is necessarily a bend in the instrument, so that the light 

 has literally to turn a corner before it reaches the surgeon's eye ; here the 

 inventor's skill and thorough knowledge of the laws of optics are brought 

 into requisition. The reflected rays of light fall upon a sort of window 

 situated a little above the lantern, and by means of prisms and a series of 

 lenses, the light is twisted and turned about until it arrives at the eye-piece. 

 No sensation of heat is to be feared, the little lamp being kept constantly 

 cool by a reservoir of water. 



Several contrivances have been invented within the last few years for 

 examining the interior of the body, but they are veiy costly ; the Gastroscope 

 is likely to render great service to medical science. 



The term " magneto-electric machine " is given to a collection of parts 

 of mechanism intended to create or gather together induced electric 



