78 ANNUAL OF SCIENTIFIC DISCOVEEY. 



both pieces, cement being interposed. From the building girder to the curb, 

 and resting on the lower flange of each, stretch-girders or joists, 12 feet long 

 and 11 inches deep, 3 feet 4 inches apart, on which the pavement plates are 

 laid and securely fastened by bolts or rivets, with counter-sunk heads, going- 

 through the flanges of the girder, the joists, and the curb. All the joints are 

 carefully cemented so as to be water-tight ; the transverse girders or joists 

 are of half-inch cast-iron, strengthened on the bottom flange by wrought-iron 

 flat bars, bolted to the cast-iron only at the two ends, and slightly expanded 

 by heating when it is put on, so as to bring the lower part of the girder into 

 a state of compression. 



IMPROVEMENTS IN CAEEIAGES. 



Mr. Michael Scott of England, has recently brought before the public a 

 three wheeled carriage designed for affording superior facility of motion, with 

 ease and accommodation to the occupants, and means of resisting the wear 

 and tear of traffic. It has two wheels behind, and a single central wheel in 

 front, as high or even higher than the hind pair. This lightens the draught 

 and simplifies the under frame-work. The driver's seat occupies the place 

 usually assigned to the rumble, directly over the hind wheels, so that the 

 reins stretch over the body of the carriage. 



Glass and Iron Axle-boxes. An invention has recently been brought out 

 by Mr. Campbell of Columbus, Ohio, for constructing cast iron axle-boxes 

 with a lining of glass on the interior. It is claimed that there is less friction 

 in these boxes, with less lubrication than in any other. 



Wilson's Improvement. In common lumber wagons the ends of the reaches 

 overlap, and are secured together by means of a pin ; in order to render the 

 length of the reaches changeable, their ends are bored with holes, placed at 

 different distances, through which the pin passes. Reaches thus bored and 

 fastened are weak, and frequently break down. An improvement patented 

 by Edward "Wilson, of Prattsburg, N. J., consists in placing a series of rack 

 teeth on the ends of each reach, so arranged that the teeth of one rack fit 

 into those of the other; when the two racks are united a sliding ring collar is 

 employed to hold them together. In order to change the length of reaches, 

 it is simply requisite to loosen the collar, set the racks as desired, and bind 

 them again with the collar. Reaches thus furnished are not bored, and are, 

 therefore, much stronger ; the coupling is also much more rigid than the old 

 plan. Scientific American. 



Green's Patent Sleeve- Axle. Mechanical journals, the records of the Patent 

 Office, and the heads of inventors, seem to be about equally full of car axles, 

 car axle-boxes, etc. ; and the good old "go-cart," with its more refined devel- 

 opments of barouche and buggy, seems to be left somewhat in the shade. 

 Occasional!}", however, a step is taken in this direction, and the Sleeve-axle, 

 although some two years before the public, may be one of those not yet suf- 

 ficiently known. The old English mail-coach patent dispensed with both 

 linch-pins and nuts at the end of the axle by placing the fastening on the 

 inner instead of outer side of the wheel. A high thin collar was turned on 



