MECHANICS AND USEFUL ARTS. 37 



when a hammer strikes a bell, indicating thereby that the vessel is in shoal 

 water ; the grapnel and weights can be lowered to any depth that may be 

 necessary, or according to the circumstances of the vessel. The whole 

 apparatus is very simple, and can be readily unshipped when not in use. 



MACHINE FOR SAWING SHIP-TIMBER. 



Sometime in the last century a reward of something like 60,000 was 

 offered by the government of Great Britain for the successful introduction 

 of machinery for shaping ship-timber, and under this liberal inducement 

 Gen. Samuel Bentham so much noted for his improvements in general 

 wood- working machinery and the elder Brunei, designed machines which, 

 at one time, promised a tolerable degree of success. These were succeeded 

 by a very massive cast-iron apparatus constructed under the direction of 

 Prof. Farey. The difficulties to be overcome in a machine of this charac- 

 ter, are certainly many and serious. We are not aware of the work having 

 been attempted in any other manner than by sawing. The ordinary saw- 

 mill must be modified in two important particulars. The cut must be 

 capable of adapting itself to any required curve, and also to any required 

 degree of "bevel." The timbers near the centre of a ship are simply 

 crooked, but from this point forward and aft, every " futtock " is beveled 

 in a greater or less degree, and this continually varying, even at different 

 points in the same frame. Some pieces near the stern are beveled in 

 various degrees and even in opposite directions, within the length of a 

 single stick. 



Bentham's and Brunei's machines were in some degree analogous to that 

 now employed in light "scroll" sawing. The machine of Prof. Farey 

 was so constructed that the movement of the saw-frame, or gate, could be 

 inclined in any required degree, but both devices were abundantly cum- 

 brous and impracticable. The only full-size machine ever constructed on 

 either principle is now standing idle at the Chatham dock-yard a useless 

 mass of heavy castings. A machine has however been lately introduced 

 by Mr. James Hamilton, of New York, which appears to combine nearly 

 or quite all the elements of success. 



In this machine the curves are described by a lateral movement of the 

 saws, while the bevels are produced by a partial rotation of the timber. 

 The stick to be sawn is suspended between centres, and controlled in its 

 position by suitable machinery on i"1.9 "tail-block." The sawgate is a 

 compound affair, and consists, first, of one principal gate, moving vertically 

 between slides in the usual manner. The crossbars forming the top and 

 bottom are polished bars of round iron, between which are stretched, with 

 liberty to move laterally, two inner frames, each carrying a saw. The 

 saws are so connected to the inner frames, by vertical pintals, that they 

 may be freely turned so as to present their teeth or cutting edges in any 

 direction. This apparatus, with various admirable arrangements of detail, 



