TRAN'SACTIONS OF THE SECTIONS. 189 



put together as these materials uow are iu ships, with no more liability to leakage, 

 but witli the remavlvable differeuce that here j-ou have a ship or floating structure 

 which is hermetically sealed against the influx of water from an_y other cause. On 

 these drums or floating cylinders the whole cable to be laid is coiled ; and, owing 

 to the greab capacity or cubical contents of any cylindrical bod}', as much cable 

 can be well and safely carried in this way for £5000 as would cost, if in a ship, 

 £30,000, or six times as much, without the safety. The cable which is now to be 

 carried bv the Great Eastern could be well carried on two cylinders costing less 

 than £8000 each. 



On a Macliine for Testing Girders. By J. L. Stoxhert and Robert Pitt. 

 The machine (which was exhibited in action to the Members of the Section) con- 

 sists of a compound steelyard le^er of the first order, from the extremity' of which 

 is suspended a pan to contain weights, the lesser lever being furnished with a 

 graduated index and a sliding weight, as in a weighing machine ; the beam under 

 proof represents the fulcrum, and the resistance is obtained by pivoting the short 

 end of the larger lever on a centre attached to a mass of stone buried in the ground 

 or to a screw pile ; the ends of the beam rest upon two moveable standards or 

 jacks, and are made to rise and fall either by screws or by a hydraulic press ; the 

 object of this arrangement (which is the principal point of novelty in the machine) 

 being to preserve the centres of the steelyards in a level line, however great the 

 deflection of the beam. The deflection is measured on a straight edge, supported 

 on standards fixed to the ends of the beam, and rising and falling with it, and by 

 means of a rod screwed to the upper flanch of the centre of the beam, and working 

 a light lever indicator moving against a quadrant scale, the deflection and set can 

 be distinctly read off to the jjgth of an inch. The pressure caused by the weight 

 of the steelyards alone is previously ascertained by actual weighing, and becomes a 

 constant quantity to be added to the indicated load. The advantages of the ar- 

 rangement consist in, 1st, perfect safety to the operator ; 2nd, great accuracy in 

 defining the weight applied, and in determining the deflection and set ; 3rd, extreme 

 facility of the whole operation, enabling girders to be proved at a cost of about one 

 shilling per ton of girder ; 4th, moderate cost of the apparatus. 



On Microscopical PJiotoqraplis of various Kinds of Iron and Steel. 

 By H.'C. SoRBT, F.R.S., F.G.S. 

 The author first briefly explained how sections of iron and steel may be prepared 

 for the microscope so as to exhibit their structure to a perfection that leaves little 

 or nothing to be desired. He then exhibited a series of microscopical photographs, 

 taken under his directions by Mr. Charles Iloole, illustrating the various stages in 

 the manufacture of iron and steel, and described the structures which they present. 

 They show various mixtures of iron, of two or three well-defined compomids of 

 iron and carbon, of gi-aphite, and of slag ; and these, being present in difl'erent pro- 

 portions, and arranged m various manners, give rise to a large number of varieties 

 of iron and steel, difFeiing by well-marked and A^ery striking peculiarities of 

 structure. 



On the Working of Underground Eailivays hy Hydraidie Power. 



By Mr. SymoNs. 



At the last Meeting of the Association Messrs. Hawthorne brought forward a 

 plan of working railways by fixed steam-engines in connexion with endless wires 

 working roimd a series of wheels placed between the lines of rail. It was suggested 

 as especially adapted for imderground railways, where it would be desirable to dis- 

 pense with locomotives. It will be obvious, however, that a very considerable 

 drawback to its adoption is the gi-eat loss of power by friction. The author of 

 this paper suggests that water-power may be substituted with advantage for the 

 continuous wire ; and he proposes, in fact, to use an endless wire of water instead 

 of one of iron whe. A great saving of power would result from the fact that, by 

 this plan, onl)' the traction- wheels actually in contact with the train would be iu 

 motion. Drawings were exhibited to show the working of the plan, 



