$58 Mr. Rawlinson^s Colour Mill, 
hard work for a man ; and then the advantage to the pub 
lie would be still farther increased. 
This machine will be found equally useful for the co- 
lours ground in water, as for those ground in oils ; and I 
doubt not but the great importance of this simple machine 
will be very soon generally experienced in all manufac- 
tories where colours are used. The labour necessary 
with this machine, in grinding colours exceedingly line, 
is very easy. It is useless to enter into any minute de- 
scription in this place, as a bare inspection of the ma- 
chine must sufficiently explain itself. 
To the colourman it would evidently be an essential 
saving of labour, and consequently of expense, which 
will probably have some weight as a recommendation; 
and the advantages to the colour- grinder have been al- 
ready stated. 
Reference to the Engraving. Plate 18, Fig. 8. 
A is a roller or cylinder made of any kind of marble r 
black marble is esteemed the best, because it is the hard 
est, and takes the best polish. B is a concave muller 
covering one-third of the roller, of the same kind of mar« 
ble, and fixed in a wooden frame 5, which is hung to the 
frame E at ii. C is a strong piece of iron, shout an inch 
broad, to keep the muller steady, and is fixed to the 
frame with a joint a if. The small binding-screw, with 
the fly-nut, that passes through the centre of the iron, 
plate at c, is for the purpose of laying more pressure on 
the muller, if required, as well as to keep it steady. I) 
is a taker- off, made of a clock- spring about half an inch 
broad, and fixed in the manner of a frame-saw, in an iron 
frame Jc, in an inclined position to the roller, and turning 
on pivots at dd. G is a slide-board to draw out occasion- 
ally, to clean, &c. if any particles of paint should fall 
from the roller, and which also forms itself for the plate 
