for measuring Standing Tirnler. llQ 



tried on a large survey, as any artist can with great ease add 

 whatever scale he pleases. The present scale allows one 

 inch m thirteen for bark, and is calculated on the.tbUowuig 

 data : The diameter of a circle whose quarter circumference 

 is 26 inches, is 33 tVo inches. The diameter of a circle 

 whose quarter girth is 6^ inches, is 8 -j-Vo inches. To gra- 

 duate the scale, the instrument is opened so as to take m at 

 the small end between the touching points 8 -%^ inches, and 

 a mark is made on the arch to denote 6 inches quarter girth : 

 it is then opened so as to take in 33 r%%- inches, and another 

 mark is then made on the arch, to denote two feet quarter 

 girth ; (these marks are made close to the inner tdge of the 

 brass on the right hand limb:) the space between them is 

 then divided into eighteen parts, which represent inches, 

 and are again divided into half, for half inches ; if any no- 

 tice is to be taken of (piarter inches, the eye will easily make 

 a further decision. 



I be"- leave to add, that it is not my intention to make any 

 for sale! I am, sir, your obedient servant, 



James BroaO. 



Reference to the Engraving of Mr. James Broad's Machine 



for measuring Standing Timber. Plate IH., Fig. 2. 



Fin-. 2. aaa a Two long pieces of well-seasoned wood, 



joined' near the middle by a pin b going through them, form- 



incr an axis on which they move, c c Two pieces of brass 



screwed near their upper ends, on the sides opposite to each 



other, and projecting over to form the measuring points. 



d The index fastened to one of the pieces of wood at e, and 



ii)ovino freely under a small bar at/, ^g Screws with nuis, 



placedin the middle of the lung slits of the two arms, to 



.. cd^^e them open, whereby the vibration is destroyed, and 



tiicarms, though light, are rendered stiff, /i A A A Screws 



and nuts to prevent the arms from splitting. 



No. 12, Downing Street, 

 Dec. 8. 1«06. 



To CiiAKLEs TAYLon, M.D. Sec. 



H4 XXII. De~ 



