60 ANNUAL OF SCIENTIFIC DISCOVERY. 



it to porno extent. Suppose, however, that this be so, the ques- 

 tion still remains: " WJiat ran^^e of llijzflit could be attained by 

 means of any power now known to us?'' This would of course 

 be limited by the quantity of material (whether petroleum, gun- 

 cotton, or anj^ other sul).stance) wliieli it would be i)ossibl(! to lift 

 into the air; and ex|)eriment alone would determine this point. 

 ^It does not seem very bold to anticipate that a range of llight 

 equal to that of a cannon-ball might be found attainable without 

 much dillieulty; and if once such a i)eginning l)e made, improve- 

 ments might l)e exi>ected to follow, enabling greater distances to 

 be performed. Another question is that of cost; this would, 

 of ct)urse, mainly di-jiend on the nature of the material available 

 for the purposes. Could the desired ol)ject be achieved by the 

 use of petroleum, the cost would be comparatively moderate; 

 wiiile if it were necessary to employ gun-cotton, the inixlure used 

 for rockets, or similar explosive cimipounds, the cost would be 

 very great. It is obvious that in anj' case such a means of loco- 

 motion would be lar more costly than thos(! now jjractised on 

 hind and water, and wholly unlilted to compete with lliem for 

 ordinary i)urposes. At the same time, it is manifest that there 

 are numerous occasions, especially in warfare, where the power 

 of moving in any desired direction througli the air, even for veiy 

 moderate distances, would be of great service ; and cost for the 

 accomplishment of such an object would not be grudged. 



ON THE USE OF STEEL FOR RAILWAY PURPOSES. 



The application of steel to many of the purposes for whieli iron 

 bad been and is now generally us(;d, had been limited b}^ the 

 difficulty in producing steel in sufficiently large masses, at a com- 

 paratively low cost, and free from flaws, with a perfect homoge- 

 neousness of material, — this seemed to present an almost insu- 

 perable difficulty to its general employment. Cast-steel made hj 

 cementation, while possessing superior hardness, lacked tenacity ; 

 if tough, it was soft; if hard, it was brittle. In 1851, however, 

 Krupp, of Essen, Prussia, showed, in the London Exhibition, an 

 ingot of cast-steel wt.'ighing 4,500 lbs., the heaviest then known. 

 In 1862, he exhiijited another one weighing twenty tons, in the 

 form of a solid cylinder, nine feet high and three feet eight in- 

 ches in diameter. It had been broken across to show its fracture ; 

 under a good microscope it Avould not exhibit a single Haw. 

 Since then he has repeatedly produced masses of forty tons 

 weight. 



There can be no reason, at this late day, and in view of the ex- 

 periments made in England and on the continent, for doubting 

 the superior durability, and the ultimate superior cheapness, of 

 steel rails and tires over those of iron. On our railroads it is 

 theoretically correct to say that the weight of a load rests on a 

 point ; but it is not practically correct. Thei-e is comjiression ; 

 much of it in the road, itself, or the rail, but some of it in the 

 wheel or tire. Yet, notwithstanding that it can be demonstrated 



