282 CJironides of Science. [April, 



6. ENGINEERING— CIVIL AND MECHANICAL. 



A GRADUAL change seems to be creeping over the minds of railway- 

 engineers, the result of which may not improbably be that some 

 long-acknowledged principles will soon become obsolete. There 

 can be no doubt that the best hne of railway, and that which is 

 most cheaply and economically worked, is the one with easiest 

 gradients and longest curves, a perfectly level and straight Ime 

 being of course the acme of perfection. It is, however, possible 

 that such advantages as to working expenses may be too dearly 

 purchased at the expense of capital, in consequence of the more 

 numerous cuttings, viaducts, and timnels that would be required, 

 and the greater breadth of land that, in the case of cuttings and 

 viaducts, would have to be purchased; attention is consequently 

 now being directed to the possibility of constructing sm-face lines, 

 the cost of which would be very small compared with that of our 

 present systems of railways. The Mont Cenis Railway has clearly 

 solved the problem as to the possibihty of working up inclines of 

 1 in 12 and round curves of only two chains radius ; and this, it 

 may here be stated, is quite practicable without the aid of the 

 central rail, the use of which is beginning to be seriously doubted. 

 Trains have indeed been worked on the Baltimore and Ohio Railway 

 up inclines of 1 in 10, where coupled engines drew alter them a 

 load equal to their own weight; on the Jefiersonville, Madison, and 

 Indianapolis Railway there is an mcline of 1 in 16^ of 1\ mile 

 in length; whilst in South Wales some of the mineral lines near 

 Aberdare are regularly worked with locomotives on inclines of 1 

 in 18. The steeper the incline, the less is the adhesion of the 

 locomotive wheels to the rails, and consequently it is capable 

 of drawing only a lighter load : under similar circumstances also 

 the resistance of a train is considerably increased; thus, on a 

 gradient of about 1 in 150 its resistance is doubled as compared 

 with working on a hivel, and trebled on a gradient of 1 in 70 

 or 75. AVith these data it is easy to calculate upon the probable 

 economy of constructing steep gradient hues, having reference to 

 their less original cost, although probably their working expenses 

 would be increased. On the Metropolitan and St. John's Wood 

 Railway, on its extension to Hampstcad, the line will have an 

 incline of 1 in 27 for | mile ; the Mauritius Railway in its ascent 

 from Port Louis rises 1817 feet to the summit, a distance of 16 

 miles, in which an aggregate length of 13,52G feet consists of 

 gradients of 1 in 27, and with engines weighing 48 tons, pas- 

 senger trains of about 50 tons are carried up to the summit 

 at the rate of 12 miles per hour, including stoppages. ]\Ir. 

 Brumlecs' proposed Metropolitan and Brighton line would present 



