122 



MR. RAWLINSON S COLOUR MILL. 



Method of 

 workjog. 



Quantity and 

 finenels of 

 grindiDg* 



This mill is not 

 a crude projeft, 

 but has been 

 ufcd feveral 

 years. 



water, and with a Tpatula or pallet-knife put on the roller, near 

 to the top of the concave muller, and the roller turned round, 

 which takes the colour under the muller without any difficulty, 

 and very few turns of the roller fpread it equally over its fui face. 

 When it is perceived fnfficiently fine for the purpofe requirccif, 

 it is very eafily taken off by means of the taker-ofT defcribed, 

 which mufl be held againft the roller, and the roller turned" the 

 reverfe way, which cleans it very quick and very completely ; 

 and the muller will only require to be cleaned when you defifi: 

 or change the colour. It is then turned back, being hung 

 on pivots to the frame at ii, and cleaned with a pallet-knife 

 or fpatula very conveniently. Afterwards, a handful of cur- 

 riers fhavings held oil the roller, with two or three revolutions 

 cleans it effeftually ; and there is lefs walle with this machine 

 than with any marble llab. 



As to the quantity ground at once on this mill, it muft be 

 regulated by the ftate of finenefs to which it is required to be 

 ground. If it is wanted to be very fine, a fmaller quantity 

 muft be put on the roller at a time ; and as to time requifite 

 for grinding a given quantity of colour, this will alfo depend 

 on the ftate of finenefs to which it is ground. I have obferved 

 that my colour-gi-inder has ground the quantity of colour \vhich 

 ufed to ferve him per day, with this machine, in three hours, 

 and, as he faid, with eafe. The colour alfo was much more 

 to my fatisfa6lion than in the former way, and attended with 

 lefs wafte. 



I have mentioned the pulverizing the colours in a covered 

 mortar, which would prevent wafte, and prevent the dnft and 

 fineft parts of noxious colours from being injurious to the 

 grinder. In fome raanufadories, where large quantities of 

 colours, prepared from lead, copper, and arfenic, are uled, 

 this precaution is particularly Tieceflary. I do not mean to fay 

 that my machine is intended to fuperfede the paint- mill now 

 in ufe for coarfe common colours. It is intended for no fuch 

 purpofe; but to fuperfede the ufe of the very awkward and 

 unmechanical marble flab now in ufe, and on which all the cq- 

 lours for china manufactories, coach-painters, japanners, and 

 colour-manufa6lurers for artifts, &c. &c. are now ground. 



Several of the colour-manufadurers have exprefled to me 

 their great want of fuch a machine ; and that I had no defire 

 of troubling the public with a machine that would not anfwer, , 



is 



