184.8. 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



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drawn in one direction, so it was with the railway manap;er. He 

 had to provide for the traffic which first came in his way, and for 

 the demands of the wealthy and commercial classes, far greater 

 accommodation. As yet, this is all that has been done ; and al- 

 though some saving has been made, yet one of the original objects 

 of tlie railway system — clieap transit — has not yet been accom- 

 plished. 



A comparatively low speed is the most economical for passengers 

 and goods, but railways have not yet been able to give the accom- 

 modation implied by this condition. To suit their general traffic, 

 and to work with safety, tliey have been obliged to work at a 

 nearly uniform speed — which has, of course, been a high one; but 

 with the resources afforded by the electric telegraph, it now ap- 

 pears possible to introduce slow and clieap trains. ^Ve long since 

 pointed out in this Journal, the plan of running trains at various 

 speeds, which was some years after advocated by the Railway 

 Chronicle ; and we are glad to see that the principle of it lias now 

 been more fully acknowledged. 



The pamphlet, now before us advocates lighter engines, lighter 

 stock, and lighter works ; but it seems that this is to be accom- 

 panied by getting rid altogether of the present high speed. There 

 can be no doubt that express trains damage the rails, points, and 

 switches, most seriously ; but we cannot now turn back. 



The present pamphlet, although it is crude and short-sighted in 

 some of its views, contains a great deal of valuable matter, and 

 in the main point of lighter stock and cheaper trains, is calculated 

 to do very much good. We, therefore, particularly recommend it 

 to our engineering readers. 



The following are the author's opinions as to the discrepancy 

 between rolling stock and rails : — 



If there be any doubt expressed as to the discrepancy of strength lietween 

 the rolling stock and the rails, a very plain answer may be found in the fact 

 of the general renewal of rails now required. If this be not enough, let the 

 proportions of the periphery of a locomotive driving-wheel hecompaieil with 

 the rail beneath it. The former weighs upwards of 200 lb. per yard ; the 

 latter from 70 lb. to 80 lb. Yet the former is of an arch form, supported hy 

 the spokes at intervals of nine inches, while the latter is: a simple straight 

 beam, supported at intervals of fifteen feet, which invariably deflect beneath 

 the passing load and destroy the continuity of support. To make a perfect 

 railw.iy, the rail-bar should he of sufficient vertical depth to resist all deflec- 

 tion, with the heaviest load passing over it. More than this, it should he 

 sufiiciently hard to prevent lamination. And the joints of the rails should 

 be so reinforced as to be equally inflexible with the solid part of the rail. 

 None of these conditions are yet attained as regards the modern class of 

 engines, and it is a problem whether they can be attained at all. Even 

 as there is a limit to the height of architectural structures relatively to their 

 base, by reason of the friability of the material, so there is a limit to the 

 weight of engines, by reason of the compressibility of iron and the impossi- 

 bility of increasing surface-hearing; for wliether a driving-wheel be of three 

 feet or eight feet in diameter, the contact with the rail can only be a point 

 or that which geometers call a " flowing point," viz., a line. Iron, according, 

 to its density, will bear a given weight without compressing, the point of 

 contact being a line. When iron has done its utmost, steel may he resorted 

 to J and, possibly, a rail of 2001b. per yard, of deep vertical section, with a 

 surface of hard steel three inches in width and three quarters of an inch in 

 depth, supported hy cross sleepers at intervals of eighteen inches, might be 

 available to construct a real " permanent way," — for the modern engines. 

 " Permanent way" is at present a lucus a non lucenilo. " Permanent main- 

 tenance of way" is a practical fact, as shareholders pockets' can testify. 



You, gentlemen, will doubtless be startled at the contemplation of the 

 outlay of capital involved in the real permanent way before described. If 

 you will not agree to this proposition, you must " try back." If you cannot 

 suit the road to the wheel, you must suit the wheel to the road. Having 

 the fear of " no dividends" before your eyes, you must turn to the practical 

 maxim of the Manchester and Liverpool directors of old, gathered from the 

 e\pericnce of the road, and keep down your weights. Light horses for the 

 high speeds : brewers' horses for the drays. Small trains and frequent, 

 with small station room, few police and porters, and fewer clerks, a slight 

 increase of drivers and stokers, and a huge decrease of plate-layers, and a 

 reduction in iron invoices, would do more for your dividends and the public 

 accommodation than the present system of elephantine traction, with a yield- 

 ing foothold — a power developed and wasted. For it must be obvious that 

 if, after expending millions to secure " good gradients," a deflecting rail be 

 laid down, it is equivalent to converting them into bad gradients. In water- 

 transit a steamboat drives a greater or lesser wave of water before her bows. 

 In rail-transit, a locomotive drives a wave of rail before her driving-wheels 

 equivalent to ascending a constant incline, and demanding a far greater ex- 

 penditure of steam-power to surmount it. The difference in the two cases 

 is, that it is impossible wholly to surmount, though we modify, the difficulty, 

 with the steamboat, whereas in the case of the rail it is practical to sur- 

 mount the difficulty altogether by proportioning the load on the wheel to the 

 strength of the rail. 



The wave line of the rails might fairly be adopted as a standard in esti- 

 mating the value of a railway ; for in proportion to the depth of the wave 



will be, catfris poribiis, the power of steam and the cost of coke. You 

 must be aware that, to ascend a constant hill, requires more horse-power 

 than to travel along a level. Y'our horse-power is steam, and the railway 

 oat is coke. If your drivers and ostlers and road trustees increase the con- 

 sumption of oats, the coach will soon he run off the road. 



But even wave lines vary. For example, rails laid on longitudinal timbers, 

 as the Great Western, yield an equable wave line. Kails laid on chairs and 

 transverse sleepers make unequal waves at their mid-length and at their 

 joints. The result is concussion as well as sinking, and the loss of power is 

 greater. Mechanical men having their living to get by the prevention of 

 waste, and the economy of steam-power, readily apprehend all this, for they 

 carry the safety-valve in their own breeches' pockets ; hut it does not so 

 readily occur to railway directors. Let them maintain a standard gauge — 

 the wave of the rails. Perhaps as an additional stimulant you will take into 

 your thoughts the somewhat startling fact that a pair of the largest railway 

 locomotives would furnish power en ough to supply the largest pumping water- 

 works in London. Another pair might achieve the tasks of delivering it 

 into their attics instead of the ground-floors of the London dwellings. 

 Another pair might pump up all the sewage water south of the Thames, as 

 Mr. Cliadwick will inform vou. 



SMELTING COPPER ORES. 



Description of the process of M.M. Rivot and Phillips, for smelting 

 copper ores. (From a paper read before the Society for the Encouragement 

 of Arts and Manufactures,Pa ris.) 



In a visit to England in 1815, one of us became acquainted with the 

 experiments made in au English copper-works, to extract the metallic 

 cupper by means of the action of voltaic electricity, from previously roasted 

 sulplmr ores df copper. The information we obtained was the same as 

 was laid before the Society as descriptive of the process employed by IVI 

 Napier. 



The sulphur ores were first well roasted, then smelted in a reverberatory 

 furnace, and the copper brought to a metallic state by passing through the 

 fused metallic silicate a very powerful voltaic current ; the grafhite hearth 

 of the furnace, aud a plate of cast-iron kept at the upper part of the 

 melted mass, forming the remaining part of the voltaic current. 



Siarting from these given points, we first tried to reduce by a voltaic 

 current, not the silicate of copper, but the pure sulphuret of copper. 



After several ineH'ec'.uhl attempts, we succeeded in passing during more 

 than two hours, a constant current through a crucible containing sulphuret 

 of copper at a red heat. 



In a common Hessian crucible, we placed two small pieces of compact 

 coke, kept at a little distance by well compressed luting ; and in these 

 we plunged two platinum wires communicating with the two poles of the 

 battery. The platinum wires were preserved from the action of the sul- 

 phur by the pieces of coke and the luting. We found in these direct 

 experiments, that coke is a good conductor at a red heat, and that the 

 luting conducts but a very little at that temperature. 



Tubes, fixed in two notches of the crucible, had for their object the pre- 

 vention of contact between the charcoal and the platinum wires, a point 

 of essential importance on two accounts :— First, the burning charcoal 

 would have established a communication between the two poles of the 

 battery outside the crucible, and consequently, a large portion, if not the 

 whole of the current would have been deviated, and not have traversed 

 the fused mass.— Secondly, the alkaline ashes of the wood charcoal would 

 have rapidly attacked the platinum wires, and the current thus have bqea 

 interrupted. The copper wires closing the circuit communicated with a 

 galvanometer, the needle of which indicated by its deviation the energy 

 of the current. We employed constant batteries with copper and zinc 

 elements, and solutions of sulphate of copper and common salt, of six to 

 twenty-four couples, and sometimes only one Hnnsen battery of thirty 

 elements. We always simultaneously made two comparative experiments, 

 by placing in the furnace two crucibles exactly similar, the one traversed, 

 and the other not traversed, by the current. 



We found, after several experiments, that the sulphuret of copper not 

 decomposed by the coke, is but very slightly decomposed by a constant 

 current of twenty-four couples of the voltaic battery, producing a deviation 

 of the needle of the galvanometer of 35 to 40 degrees. 



By employing a Bunsen battery of thirty elements, producing a devia- 

 tion of the needle of the galvanometer of 4-5 to 50 degrees, we have reduced 

 a notable quantity of copper in a state of fusion ; but the largest propor- 

 tion of the sulphuret remained undecomposed. 



These results convinced us that the action of the battery is feeble as 

 regards sulphuret of copper, and that the very powerful voltaic current 

 requisite for effecting the decomposition, as well as the difficulty of con- 

 veniently disposing the apparatus, would prevent the employment of this 

 process for the treatment of sulphuret of copper, and o portion for that 

 of pyritic copper, which is the most common ore of copper. 



Experiments analogous to the preceding, in the which wo replaced the 

 two poles of coke by rods of iron, have indicated to us that the action of 

 the battery renders more rapid, but not complete, the reduction of sul- 

 phuret of copper by the iron. It always forms a mass, rich in copper. 



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