30 ANNUAL OF SCIENTIFIC DISCOVERY. 



water and dried for two hours." The fact that these fibres thus be- 

 come explosive was first noticed by Professor Otto, about fourteen 

 years ago, but it was not fully explained and brought to public notice 

 till 1845. It is the substance called gun-cotton by Professor Sehon- 

 bein, and xyloidine by M. Pelouz. Considering the very intense 

 power of xyloidine, it is the most easily controlled substance we 

 know of, as by compression its explosion can be retarded or wholly 

 prevented. For an engine of two-horse power, a thread of this in- 

 gredient, not larger than sewing-cotton, is sufficient, so very explosive 

 is it, and the Count expects that it will cause steam-engines to be- 

 come obsolete, as he thinks he can successfully apply his new disco- 

 very to all manners of locomotion, &c. 



THE STEAMBOAT NEW WORLD. 



EVERT year sees some new steamboat constructed which surpasses 

 in size, magnificence, or speed those previously made. There is no 

 doubt that the mechanics of this country excel those of any other in 

 their inland steamboats, and it is also probable that in a few years 

 the same can be said of our sea-going steamships, though it must be 

 allowed that those hitherto produced are, with few exceptions, decided 

 failures. During the present year, the new steamboat New World 

 has commenced running. She is said to be the longest boat ever pujt 

 on the stocks in this country, and the longest ailoat in the world. 

 Her length is 373 feet; extreme width, 69 feet; the engine is 76 

 inches in cylinder, 15 feet in stroke, and the wheels, of iron, 46 feet in 

 diameter. She draws 4 feet of water. The engine is a low pres- 

 sure one, and though the boat is so very long she obeys the helm 

 with great readiness. Her decorations are all of the most superb and 

 costly character. 



[If we ever attain any greater speed either in our inland or sea- 

 going steam-vessels, it will be principally by enlarging their size. 

 Though some improvements will doubtless be made in the engines 

 and in the models of the vessels, yet the great gain will be by in- 

 creasing the tonnage, for the reason that the size, and consequent 

 room for engines and coal, increases much faster than does the op- 

 position caused by the water and the air. Editors.] 



ON THE PADDLES OF STEAMERS. 



THOMAS EWBANK, ESQ., the present Commissioner of Patents, has 

 communicated to the Journal of the FrarJdin Institute an account of 

 some experiments made on the paddles of steamers, for the purpose 

 of ascertaining the best form and material for them. He thinks that 

 there can be little doubt that the greater the velocity of a steamer's 

 wheels the fewer (within certain limits) should be the blades, and 

 that in many of our boats the number might be advantageously re- 

 duced. One blade in the act of plunging, another sweeping under 

 the shaft, and a third leaving the surface, are all that is necessary to 



