T.nprovcd Mill for grinding Painters' Colours. 177 



I have seventy-two square inches of the concave marble 

 tnuUer in constant work on the paint, and that I can bring 

 the paint mlich oftener under this muller in a given space 

 of time, than I could by the usual method with the pebble 

 muller, which is seldom more than four inches in diameter, 

 and conscquentlv has scarcely sixteen square inches at work 

 on the paint, when my concave muller has seventy-two. 

 I do not mean to sav that a roller, the size of that which I 

 now use, is the largest which might be employed ; for truly 

 I believe that a roller two feet in diameter, v^ iih a concave 

 muller in proportion, would not be hard work for a man ; 

 atid then the advantage to the public would be still further 

 increased. 



This machine will be found equally useful for the colours 

 ground in water, as for those ground in oils ; and I doubt 

 not but the great importance of this simple machine will 

 be verv soon generally experienced in all manufactories 

 where colours are used. The labour necessary with this 

 machine, in grinding colours exceedingly fine, is very easy. 

 It is useless to enter into any minute description in this 

 place, as a bare inspection of the machine must sufficiently 

 explain itself. 



To the colourman it would evidently be an essential saving 

 of labour, and consequently of expense, which will proba- 

 bly have some weight as a reconnuendation; and the ad- 

 vantages to the colour-grinder have been already stated. 

 I auj, sir, your very obedient servant, 



James Rawlixsox. 

 Charles Taylor, Esq. ^__^ 



SIR, 



I WAS didy favoured wiih your letter of the 3d instant; 

 and in reply to the questions that the committee have pro- 

 posed, 1 have made a rough sketch of the machine, vvitii 

 letters of reference, as supposing this may better explain 

 the process. Plate IV. fig. 1. A is the roller or cylnidcr 

 made of any kind of marble : black marble is esteemed the 

 best, because it is the hardest, and takes the best poli;'h. 

 B is the concave muller covering one-third of the roJL;-, 

 and of the same kind of marble, and is fixed in a woDdcn 

 frame I, which is hung to the frame E at ii. C is a piece 

 of iron, about an inch broad, to keep the muller steady, 

 and is fixed to the frame with a joint at f. The small 

 binding-screw, wiih the fly-nut, that passes through thii 

 centre of the iron plate at c, is for the purpose of laying 

 more pressure on the muller, if required, as well a* t,o keep 



Vol. 21. No. S?. March 1305. M it 



