472 



PAINTS, GRINDING OF 



BB, but may be preferably supported upon the three points of adjustable screws, 

 passing up through bearing-bars. The millstone, c, is surrounded by a large iron 

 hoop, D, for preventing the pasty-consistenced colour from running over the edge. 

 It can escape only by the sluice-hole E, Jiff. 1 584, formed in the hoop, and is then 

 received in the tub x, placed beneath. 



The upper or moving millstone, F, is also made of cast iron. The dotted lines iudi- 



1584 



cate its shape. In the centre it has an aperture with ledges, o, o ; there is also a 

 ledge upon its outer circumference, sufficiently high to confine the colour which may 

 occasionally accumulate upon its surface. An upright iron shaft, H, passes into tho 

 turning-stone, and gives motion to it. A horizontal iron bevel -wheel, x, figs. 1584, 

 1585, furnished with 27 wooden teeth, is fixed upon the upper end of the upright 



1585 



1586 



I" 



--[ 



1" 



d d 



shaft H. A similar bevel-wheel, L, having the same number of teeth, is placed verti 

 cally upon the horizontal iron axis M M, and works into the wheel K. This horizontal 

 axis, Ji M, bears at one of its ends a handle or winch, N, by which the workman may 

 turn the millstone F ; and on tho other end of the same axis the fly-wheel, o, is made 

 fast, which serves to regulate the movements of the machine. Upon one of the 

 spokes of the fly-wheel there is fixed in like manner a handle, P, which may servo 

 upon occasion for turning the mill. This handle may be attached at any convenient 

 distance from the centre by means of the slot and screw-nut J. The colour to be 

 ground is put into the hopper n, below which the bucket, s, is suspended for supplying 

 the colour uniformly through the orifice in the millstone o. A cord or chain, T, by 

 means of which the bucket, s, is suspended at a proper height for pouring out tho 

 requisite quantity of colour between tho stones, pulls the bucket obliquely, and m;iki's 

 its beak rest against the square upright- shaft H. By this means the bucket is con- 

 tinually agitated in such a way as to discharge more or less colour, according to its 

 degree of inclination. The copper cistern, x, receives the colour successively as it is 

 ground ; and when full it may be carried away by the two handles z z ; or it may be 

 emptied by the stopcock Y, without removing the tub. For many purposes, as for 



