70 TRANSACTIONS OF THE 



torn, but separated at the top. As the chisel, if freed down a 

 double armed lever, acts upon these, two springs forcing them 

 together. The power of one of these springs is adjustible by 

 means of a screw on the correcting rod. [A diploma awarded. 



JVo. 1709 — Mitre and Dovetail Machine. 

 F. A. Gleason, Rome, N. Y. If the inventor will allow us to in- 

 sert the word " grooving," we can recommend this instrument as 

 very useful in manufactures where neatness, not strength, is re- 

 quired at the joints; and where a dove-tailed groove is required 

 in the solid wood, it will apply in strong work. But as a dove- 

 tailing machine, thence inferring a claim to supercede the instru- 

 ment that makes genuine dove-tails for strong work, we should 

 pass it as useless. The principle is, to form a dovetailed groove 

 in the mitre of one piece, and a dovetailed tongue in the mitre 

 of the adjoining piece, at any desired angle, according to the 

 number of sides desired; the mitre and tongue in one piece, or 

 the mitre and groove on the other being formed at one operation 

 by means of two cutters flaring from two that are at right angles 

 with the motion, the former cutting the groove or tongue, and 

 the latter the mitre. The proper angle is given by an adjustible 

 frame upon which the boards are slid along as the cutters re- 

 move the wood. [A diploma awarded. 



JYo. 1806.— Model of a Saw Mill. 

 C. B. Hutchinson, Auburn, N. Y. Same as full sized saw and 

 support, No. 1164, " Back Guard Saw." 



This is an admirable contrivance if in practice the saw be not 

 subject to haggle. 



In this arrangement there is no saw-gate, but in lieu of it a 

 saw-blade without teeth, a little thicker than the actual saw, 

 stretched between the top and bottom frames of the mill as a 

 support behind the saw for its whole length. Against this steel 

 plate rests the saw, having the lower end attached to the pitman, 

 while the upper end simply is held in its place sidewise by cast 

 iron guides above the top, having a slat on each side with a pin 

 through the saw. Thus the saw must be pushed up, and has to 

 depend entirely on its own stiffness. We apprehend that not- 

 withstanding the saw-blade support passes through the log and 

 supports the saw from end to end, still, when the saw becomes 

 dull and meets with hard wood, as a hemlock knot on the side 

 of a log, it may run from its course. If this be not the case, 

 then it is evident that the absence of the gate is a great ad van- 



