A Sketch of his J Fork as a Craniologist 37 



O. — A binding-nut, for securing the stage G in position when 



its adjustments have been completed. 

 P. — A pivot, rising vertically from the brass mounting of the 

 foot B. Its centre coincides with the axis of the stage G, 

 when the poles of the latter are placed perfectly vertical, 

 and if extended vertically, would exactly bisect the same 

 axis when adjusted horixontally. 

 Q. — A brass carriage, 12 inches long and 2^ broad. One of 

 its extremities is perforated to make it fit pivot P, round 

 which, resting upon B, it moves horizontally ; the other 

 extremity resting upon a brass foot, R, which raises its 

 under surface to the level of the top of B. When moved 

 round P, it describes a circle, of which P is the centre, and 

 its left limb is graduated to permit of the distance from P 

 to U being read off in inches and tenths. 

 R. — The foot upon which Q rests, secured to it by screws. 

 S.— A brass slide, which travels backwards and forwards in a 

 slot upon the carriage Q, carrying at one end the upright 

 T, and having at the other end a tube for receiving the 

 pencil U. 

 T. — A perpendicular triangular brass upright. 12^ inches long, 



attached to S. 



U. — A pencil, passing freely through S, which it accompanies 



in all its movements, with its point resting on the paper Y. 



V. — A spring slide, fitting accurately upon, and moving freely 



up and down T. It carries in front a horizontal pivot, 



upon which rotates the curved tracer W ; and at the back^ 



a binding-screw, to fix it in position when requisite. 



W. — A curved tracer, so adjusted as always to have its points in 



the same perpendicular line as the point of the pencil U. 

 X. — A pointed steel pin, furnished with a wooden handle. It 

 passes through the exact centre of P ; pierces the paper Y ; 

 and indicates the precise point from whence all the measure- 

 ments are taken. 

 Y. — A sheet of paper, extending under a portion of the foot B ; 

 which, when screwed down, holds it firmly in its place. 



