MR. RAWLINSON's COLOUR MILL.' U9 



Every thing being llms arranged, carbonate of lime diluted Defcription of 

 with a Tmall quantity of water is to be poured into the bottle ^Jj ^ct^i^oj^of 

 F, and after all the joints of the tubes have been luted with procuring gafi- 

 great care, afire is to be kindled in the furnace. As foon^'^'f ^'"'''^^ "^ 



n * . carbon. 



as this fire is fufficicntly Rrong to make the gun-barrels red-, 

 hot, fulphuric acid is to be poured into the funnel G, and, ' 



when it comes into contact with the carbonate of lime in ihb 

 bottle F, it will expel a large quantity of carbonic ac?d. 

 This acid prefently pades through the tube E into the barrel 

 B, is conveyed from B to D through the tube H, from D to 

 C through the tube I, and thence ilfuing by the tube K, comes 

 out beneath the receiver M, placed on the flieif of the pneu- 

 matic tub. 



The obje6l propofed by Mr. Baruel in this arrangement of 

 his apparatus, was to oblige the carbonic acid gas evolved 

 from the carbonate of lime, to traverfe the charcoal con- 

 tained in the ihree gun-barrels, and thus laturate itfelf with 

 all the carbon it could take up. 



In fad it is eafy to conceive, that this method mufl be This method 



more certain and expeditious than that formerly emploVed, "'"^^ ""^'" f"i) 

 J. . ^ . . , „ , t J ' expeditious than^ 



when the operator was (atistied with palling the gas through ttie old j 



a fingle bairel. It is true it was collc6ted, and fubjeded to a 

 fecond operation, or even to a third ; but this mode Was te- 

 dious and much of the gas was always loft. In this new for nothing is 



method on the contrary nothing is loft, and a produd is r<*na- 'oft, and the pro- 

 ,,•'„„ f. , . . ^ dudl i« obtained., 



rated at once, which poijefies all the properties that character- at oncij. 



ife the gafiform oxide of carbon, and which may be ufed un- 



fparingly, iince it is always obtainable;,in large quantity. 



XVII. 



Defcriptinn nf an improved Mill for levi<ratmg Painters Colours. ' 



Li/ Mr, James R a wl i n s o n , of Derbj/. * 



A HE hitherto very unmechanical, inconvenient, and highly Great inconve- 

 injurious method of grinding poifonous and noxious colours, "'^""^ and un- 

 11 ~ n ' • I 1 rji . ,. wholefome ef- 



Jed me In it to imagme a better might eahly be contrived for feds of grinding 



that purpofe. It mufl be obvious to every per fon, that the *^°'""''s on the 



Hone, - 



** From the Memoirs of the Society of Arts for 1804, who 



awarded him the lilver medal. 



W •method 



