106 LONDON INSECTS 



easily as straight forward, it can kill right and left, and 

 laugh at such poor fliers as the Swallows. 

 Primitive man having 



' Learnt of the little Nautilus to sail, 

 Spread the thin oar, and catch the driving gale,' 



it has been reserved, we are now told, for this genera- 

 tion to be taught that all such clumsy contrivances as 

 screws and paddles may be dispensed with if builders 

 will only apply to ships the principle of propulsion 

 which young Dragon-flies have known for thousands 

 of years ; from times long before there was a man in 

 the world, for there are traces of Dragon-flies in the 

 rocks of very early dates. 



In The Times of the 17th October 1883 was an 

 account of the trial trip of a new German ship driven 

 by hydraulic reaction on the Elbe, near Dresden. 



' Noiselessly and without any oscillation,' wrote the 

 Berlin correspondent, ' did the large vessel large as 

 compared with the steam-craft plying on that part of 

 the river after the simple turning of a lever by the 

 captain on the bridge, commence its trial- trip, stem- 

 ming the current and keeping an even course under 

 the picturesque right bank of the river. The only 

 noise audible was that of the rushing of the water 

 from the tubes, fixed a little above the level of the 

 river, and nearly amidships, on both sides of the vessel. 

 Another turn of the lever, and the action was reversed. 

 The vessel comes to a dead stop in less than her own 

 length.' 



The larvae of the Dragon-flies shoot themselves 



