22 ANNUAL OF SCIENTIFIC DISCOVERY. 



weigh 150 tons each; the transverse beams, placed 4 feet asunder, 

 weigh 82, and the cast-iron 10, giving 392 tons as the total weight of 

 the bridge. The girders were constructed on one side of the river 

 and hauled across on rollers to the other side ; but great difficulty was 

 experienced in this, as of course the girders during this process could 

 rest upon but few points, and one end of them must sometimes be sus- 

 pended for 120 feet, before it received any auxiliary support. Eng- 

 lish Railway Chronicle. 



SUSPENSION BRIDGE AT PESTH. 



THE suspension bridge which is erected over the Danube, at Pesth, 

 was commenced in 1840, under the direction of an English engineer, 

 and was finished in January, 1849, at a cost of 3,200,000 dollars. This 

 bridge has a clear water-way of 1,250 feet, the centre span or opening 

 being 670 feet. The height of the suspension towers from the foun- 

 dation is 200 feet, being founded in 50 feet of water. The sectional 

 area of the suspending chains is 520 square inches of wrought iron, 

 and the total weight of the same is 1,300 tons. This is the first per- 

 manent bridge which has been erected over the Danube below Vienna 

 since the time of the Romans. Journal of Franklin Institute for May. 



APPARATUS FOR FEEDING STEAM-BOILERS. 



A PATENT has been issued to Mr. Warren S. Bartle, of Newark, 

 N.J., for an improved apparatus for feeding steam-boilers. It is dif- 

 ficult to give a correct idea of it without the aid of plates, but we 

 Mill endeavour to describe the more important parts. A small cylinder 

 is erected and attached to a convenient part of the boiler, communi- 

 cating with it by a pipe above for steam, and one below for \vater. A 

 float is placed in this cylinder, M'hich as it rises and falls turns a cock, 

 to shut off and open the suction-pipe of a force-pump, so as to regu- 

 late the supply according to the depth of water in the boiler. To ef- 

 fect this turning of the cock, the float is connected by a rod to an arm, 

 which passes through a steam-tight bearing box. Fastened to this 

 arm is a Mire, Miiieh is nicely balanced on it, and is fastened below to 

 two adverse ratchets, \vhich in turn are accurately balanced on pivots 

 in a small upright standard. As the float rises and falls in the cylin- 

 der, these ratchets turn a ratchet-wheel, M'hich shuts or opens the 

 suction-passage of the force-pump. The passage is opened to its 

 greatest extent when the float is at its lowest line, and when it is at a 

 certain height it is shut up entirely. By some additional machinery 

 the action of the pump is wholly shut off, and the inventor claims as 

 his, various modifications of this apparatus. Scientific American. 



NEW STEAM-BOILER FEEDER. 



THE Scientific American describes another new apparatus for feed- 

 ing boilers, whereby the force-pump is done away with. It is so con- 

 structed that the water will be kept continually at the water-line, and 



