38 ANNUAL OF SCIENTIFIC DISCOVERY. 



constitutes the invention which promises completely to supersede the broad- 

 axe and bevel-rule. 



Both sides of the timber are cut at the same moment. The rough timber, 

 properly marked with the required curves upon its upper surface, is fed up 

 to the saws in the usual manner. The saws once fairly entered in the 

 wood, and controlled in their position by the hands of the attendant, 

 readily follow (by the free lateral movement of the inner within the main 

 gate) the most difficult curves ever required in practice. Even a transverse 

 cut may be readily made by a proper manipulation of the saws. The 

 devices for controlling the amount of bevel are capable of effecting the 

 most delicate gradation from one end of the stick to the other ; and in this 

 respect, as indeed in every other, the work of the machine exceeds in 

 accuracy that of the ordinary tools. 



BENDING SHIP-TIB1BEE. 



Machinery for giving different curves and increased strength to heavy 

 timbers used in ship-building and for other purposes, has recently been 

 constructed by the well-known inventor, Thomas Blanchard, of New 

 York. The principle upon which the force is exerted is very simple. An 

 iron model, with a large groove corresponding to the shape of the knee, 

 passes in its whole length under a cogged wheel, whose cogs fit into corre- 

 sponding grooves in the surface of the model, and performs a semi-circular 

 revolution. It receives into its anterior extremity, which starts under the 

 wheel, the stick of timber to be bent, and fits over it as it lies upon the 

 horizontal frame which supports the machinery, receiving the stick into its 

 groove up to the spot where the curve begins, where the model rises from 

 the frame as the knee of the ship rises from the water. The horizontal 

 framework has also a groove into which the stick is received, and at its 

 further end an iron plate is forced against it steadily by a screw, giving a 

 strong and uniform "end pressure" in the direction of its length. It 

 lies upon a flexible iron band, which is attached to the end of the model, 

 where the stick rests. As the anterior end of the model passes under the 

 cogged wheel and rises to a right angle with the frame, carrying with it 

 the stick of timber bound in its groove by the flexible iron band, its pos- 

 terior extremity descends fitting over the timber until it is level with the 

 frame. The stick of timber has now taken the shape of the mould, and 

 when cold, retains its shape with as much tenacity as if it had grown into 

 it. It is very evident that when a straight stick of timber is bent into a 

 semi-lunar shape, the fibres of the wood upon the inner side must be 

 packed more densely. The wood is steamed for from half to one hour for 

 each inch of thickness, and put into the machine warm and moist, and as 

 it takes its bent position the inner fibres are impacted without destroying 

 the tissues of the wood, but only increasing slightly its density on the 

 inside of the curve. 



