40 ANNUAL OP SCIENTIFIC DISCOVERY. 



be returned for similar houses, that the inventor was soon compelled to 

 increase his force so as to make his factory one of the leading industrial 

 establishments of New York. A cast-iron building from this establish- 

 ment has been put up in Baltimore, for the office of the Baltimore Sun, 

 which ranges for 150 feet on two streets, and is five stories in height. 

 During the past year, a tower of cast-iron has been erected in New 

 York, to sustain a fire-bell, weighing 20,000 pounds. This tower is 

 ninety feet in height and twenty feet in diameter. Some three years 

 since, when the first iron building was erected in New York, consent 

 was very reluctantly given by the authorities to its construction, on the 

 ground of danger to firemen from bursting in case of fire. 



TUBULAR WROUGHT-IRON MASTS AND SPARS. 



Tins invention, by Capt. C. F. Brown, of Warren, R. I., consists in 

 the employment of masts, yards, and other spars of wrought-iron tubes 

 fitting within one another in a manner similar to the joints of telescopes, 

 the larger tubes forming the larger part or parts where the greatest 

 strength is required, and the innermost or smaller tubes forming the 

 ends, the whole number being secured together by a screwed rod or 

 rods, made secure to the larger outside tube or tubes, and passing 

 through nuts in the inner ones. The several tubes can be set in any 

 position by setting-screws, so that the length of each mast, or spar, 

 may be varied at pleasure. The upper masts are to be made in the 

 same way as the lower ones, and to fit into them, and be secured by 

 other screw-rods secured to the upper joints of the masts immediately 

 below them. The gradual diminution of the size of the tubes gives the 

 necessary taper to both the mast and yard, and each may be formed of 

 any number of joints necessary for the purpose intended. The masts 

 and spars, when stowed away, can be screwed into one another, or the 

 screw-rods may be taken out, and the tubes slipped into one another, 

 thus enabling them to be stowed away in very little space. Any spars 

 may be made in the same way. Scientific American. 



WROUGHT-IRON TUBULAR CRANES. 



THE same principle adopted in the formation of the Britannia Tubular 

 Bridge, has been applied by Mr. Fairbairn, to the construction of a 

 crane for lifting heavy goods. This crane is entirely composed of 

 wrought-iron plates, firmly riveted together, and so arranged that the 

 upper side is particularly well adapted to resist tension, and the under, 

 or concave side, embodying the cellular construction, to resist com- 

 pression. The form is correctly that of the prolonged vertebrae of the 

 bird, from which the machine takes its name. It is truly the neck of 

 a crane, tapering from the point of the jib, where it is two feet by 18 

 inches wide, to the level of the ground, where it is five feet by three 

 feet six inches. From this point it again tapers perpendicularly to a 

 depth of 18 feet, under the surface, forming a cone, the bottom of 

 ^vvhich terminates in a cast-iron shoe, which forms the toe on which the 

 crane revolves. The lower or concave side, which is calculated to resist 

 compression, consists of plates forming three cells, and varying in thick- 



