MR. RAWMNSO-n's colour MILL. 121 



*ng colours exceedingly 6ne, is very eafy. It is ufelefs \o 

 enter inlo any minute defcription in tliis place, as a bare In- 

 ipe^ion of the machine muli fudiciently explain itfeJf. 



To the cojoiirman it would evidently be an efTential f^iving 

 of labour, and confequently of expenfe, which will probably 

 have Tome weight as a recommendation ; and the advantages 

 to the colour-grinder have been already ftaled. 



Plate V- fig. 3, A is a roller or cylinder made of any kln^ Defcription, by 

 of marble; black marble is efteemed the beft, becaufe it is ^^^^j" ^ 

 the hardefl, and takes the bed polift). B is a concave muller 

 covering one-third of the roller, of the fame kind of marble, 

 and fixed in a wooden frame b, which is hung to the frame 

 E at ii, C is a ftrong piece of iron, about an inch broad, 

 to keep the muller fteady, and is fixed to the frame with a 

 joint at f. The fmall binding.fcrew, with the fly nut, that 

 pafles through the centre of the iron-plate at c, is for the 

 purpofe of laying more prefiure on the muller, if required, 

 as well as to keep it fteady, D is a taker-ofT, made of a 

 clock-fpring about half an inch broad, and fixed in the manner 

 of a frame-favv in an iron frame k, in an inclined pofition to 

 the roller, and turning on pivots at d d. G is a flide-board to 

 draw out occafionally, to clean, &c. if any particles of paint 

 fliould fall from the roller, and which alfo forms itfelf for th^ 

 plate H, to catch the colour on as it falls from the taker-off. 

 £ is a drawer, for the purpofe of containing curriers fliavings, 

 which are the bed things for cleaning paint-mills,— -E is the 

 frame. 



Previous to the colour being applied to the mill, I Giould Pulverization, 

 recommend it to be finely pulverized in a mortar, covered in °" '^f^' g'"'n'^l"gf 

 the manner of the chemilbvy hen they levigate poifonousdrugs*. g3^^QIl, 

 This procefs of dry-grinding is equally necetfary for the mj^,rbl(| 

 Oab now in ufe ; after vyhich it iliouid be mixed with oil or 



• Or rather in an improved mill, ufed af Manchefter by Mr. 

 Charles Taylorj, for grinding indigo in a dry ftate, of which I 

 have annexed a drawing, and reference, to render the whole buli- 

 ncfs of colour-grinding complete. — Note of the Author, 



This is the fame apparatus as was ufed under the name of a phir 

 hfophical m'dly in the laboratoiy at Gottorp, about the begipnipg of 

 the iaft century. See the memoir of Dr. Joel Langelotji with an 

 engraving, in Lowthorp's Abridgment of the Philofophical Tranf- 



^aious, ii|. 3;^.— w. N. 



water. 



