VIII NOTES BY THE EDITOR. 



limits, with a very great improvement iu regard to strength and 

 durability. 



The French Railway Companies are also extensively introduc- 

 ing rails of Bessemer steel upon their roads. These rails, as 

 manufactured at the principal French works, cost from 60 to 70 

 dolhirs per ton. 



There is a growing feeling among engineers and steel makers, 

 that the compound rail, made wholly or partly of steel, will 

 prove more safe and economical than any solid rail, for, if the 

 same durability of track can be obtained with a steel cap as 

 with an all-steel rail, the first cost will be greatly decreased. A 

 rail made in two or three continuous parts, breaking joints, is 

 also a practical insurance against disaster from broken rails. 



It is estimated that in the United States from 40,000 to 50,000 

 tons of steel rails are in use on our various railways. 



The Lehigh and Susquehannah is entirely built of steel. 

 Other railways are using them largely, the Hudson lliver, 

 Erie, and Pennsylvania Railways using 10,000 tons or more 

 each. The last report of the New Jersey Railway and Trans- 

 portation Company says: "It is probable that steel rails will 

 be gradually laid the entire length of the road, the greater 

 durability of these rails overcoming the objection to their in- 

 creased cost." 



The use of steel rails will guarantee greater safety of life 

 and limb, and their introduction, therefore, should be hailed 

 with delight, for the term American rails has become a synonym 

 for the cheapest and least durable rails manufactured. 



Our late war taught us much in regard to ordnance and iron 

 ships. The great advances in the manufacture of steel, and the 

 discoveiy of new explosives, are destined to materially further 

 our knowledge. 



The most noteworthy improvement of this year in fortifica- 

 tions is Captain Moncrief's system. By an ingenious device 

 he lowers his gun upon its rocking carriage after tiring, and 

 thereby does away with embrasures (the weak places in pro- 

 tecting works), while he gains the advantage of reloading his 

 gun in comi)arative of safety. 



What inlluence the new explosives, picrates, dynamite, and 

 ammonia powder will have on warlike operations, remains to be 

 seen. 



Attention has lately been turned to gas as a calorific agent. 

 Profs. Silliman and Wurtz, by their researches, promise to in- 



