22 ANNUAL OF SCIENTIFIC DISCOVERY. 



ball, and 30 pounds of powder, against a target of 4i-incli iron 

 plates, backed with timber and sand. The plate was indented six 

 inches, but not actually penetrated, and was exhibited along with the 

 gun. During the process of forging it was necessary to move these 

 heavy masses with ease and rapidity, just as a blacksmith handles his 

 iron ; and, in order to effect this, most powerful mechanical appli- 

 ances and the exercise of great skill must have been indispensable. 



The Exhibition contained many very interesting illustrations of 

 welding under difficult conditions, and of these we will notice a few, 

 without attempting, for want of space, any description of the processes 

 employed. The Butterley Company, above referred to, showed a 

 girder in the form of a double T, twelve inches across each end, 

 and three feet deep, welded longitudinally. A large, stamped, solid 

 wrought-iron wheel was shown in the English department, as an ex- 

 ample of combined strength and cheapness. Illustrations of the suc- 

 cessful welding of iron and steel in railway tire bars were shown by 

 the Monkbridge (English) Company. In these the melted steel was 

 cast round an iron tire, the latter being first heated to redness and 

 dusted over with borax powder. The union of the two metals in the 

 specimens exhibited seemed perfect, and even where the combination 

 was hammered out into thin plate there was no sign of any separa- 

 tion. This process is the invention of a Frenchman, and promises to 

 be very valuable. The French, indeed, have recently made such 

 progress in the manufacture of iron, that bars of beam-iron are now 

 constantly exported to England from France as an article of com- 

 merce. Another curious fact, bearing upon the vexed questions of 

 tariff and free-trade, brought out during the past summer in a pub- 

 lished correspondence in the London Times, was, that Belgium, which 

 for years past (and at the present time) has maintained a prohibitory 

 duty on the importation of foreign iron, not only undersells British 

 rolled and bar iron in foreign markets, but even largely exports the 

 same products into Great Britain. 



Among the curiosities in this department were two bars of mallea- 

 ble iron : one, which had been tested by the admiralty to 64 tons per 

 square inch, the standard strain being 59 tons, and which broke the 

 admiralty chains instead of yielding ; the second, which had been 

 tested with a strain of 51 tons, by Mr. W. Fairbairn. There were 

 also several pieces of crystalline iron, polished like silver, and sus- 

 pended by silken cords, which, when struck, emit a note as clear as a 

 bell, showing the perfect homogeneous character of the metal. 



Chain Cables. The prize medal for the best chain cable was 

 awarded for a patent plan invented by Sisco and Sinibaldi. The 

 links of this chain are oval in shape, made from hoop iron, galvanized 

 and brazed. The hoop is wound on a reel by a machine, the inven- 

 tion of the patentees, till the thickness required is secured. It is then 

 passed through a furnace of molten metal, and afterwards rounded 

 off for the completion of the latter operation of brazing. Between 

 the links there is a stay as in the ordinary chains. The principle 

 may be understood by taking a long slip of paper, or tape, and roll- 

 ing it round the hand, lay upon lay, till the necessary thickness of 

 a chain is gained, then placing a stay across the inner part of the 

 oval thus formed, and a good idea is obtained of Sisco and Sinibaldi's 



