9 



were often attacked and injured by the mob and their instruments 

 broken. 



The hydrauHc railway, or " Chemin de Fer Ghssant," which 

 was inaugurated at the Paris Exhibition, and in which Sir Edward 

 Watkin takes so great an interest, is an ideal mode of travelling 

 as regards swiftness of motion ; the sensation resembles that of 

 travelling in a sledge over ice in perfect condition, and is, in fact, 

 similar in method, the carriages being mounted c n sledge plates, 

 between which and the rails a thin film of water is interposed. 

 The propulsion of the train is effected by horizontal columns of 

 water from hydrants placed at intervals along the lines. M. Barre 

 claims for his invention that the speed of 140 miles an hour can be 

 obtamed ! Sir F. Bramwell considers the experiment highly 

 interesting, but his opinion, in which the majority of our leading 

 engineers coincide, is that it will hardly answer for long distances 

 or for heavy commercial traffic. When we remember, however, 

 that sixty years ago George Stephenson was the only engineer in 

 this country who believed in the ultimate triumph of the steam 

 locomotive, we shall beware of asserting that any new invention or 

 suggested improvement is an impossibility. 



One of the most important factors in the Naval warfare of the 

 future, is to be, we are assured, the pneumatic dynamite gun, 

 which was recently tested in the novel American torpedo craft, 

 the Vesuvius. Captain Zalinski's invention displayed in its trial 

 performance a capacity of throwing projecti'es beyond even the 

 claims of the contract, which stipulated that 15 shots should be 

 fired in 30 minutes, whereas tlie actual result was, that 15 shells, 

 each eight feet in length, and 15 inches in diameter, and holding 

 respectfully 2001bs. of explosives, were discharged in 16 minutes 11 

 seconds. The pneumatic pressure used in throwing these shells 

 was 7501bs., but the air reservoirs are capable of contaiuiug a 

 volume of 2,000 lbs. The range is obtained by varying the pressure 

 of air behiud the projectile. Although many of these guns are 

 ordered by the American government, the Vesuvius is, at present, 

 the only vessel where they are mounted. She is a large torpedo 

 boai of 246 feet in length, and 26 feet in breadth, and carries as 

 her chief armament three of these Zahnski guns, fixed parellel 

 with one another, at an angle of 16 degrees above the horizon. 

 The guns are capable of throwing shells containing 100, 200, or 

 6001bs. of explosives, and can thus fire a broadside of over 1,500 

 lbs. of dynamite per minute. With weapons of such deadly power, 

 a few shells would suffice to wreck any vessel or tort which came 

 within their range, and as the Vesuvius has a freeboard of only 

 5 feet, she does not herself afford a prominent target to the enemy. 



In our own country, considerable advance has been made in the 



