g«J^ mPROVfiMENT IN THE AQUATINTA PROCESS. 



bH«»reen 30° and 40% that is between \ and ^ of the appa- 

 rent distance from the zenith to the horizon. These points 

 of division of the apparent firmament answer to 14° ami '-^0°* 

 of real altitude: and that of 18!, wjjich you have measured, 

 is between these two. I onght however to add, that the ob- 

 server in question ultimately fixed on tlie eatiniate ofa third, 

 or 30° apparently. But all these determiua-tions are neces- 

 sarily approximations only. 



XV. 



Improrement in the Aqvatinta Process, hy which Pen, Pencil, 

 and Chdlk Drawings can be imitated ; by Mr. J. H assell. 

 No. M^ClemenVs Inw\» 



SIR, 



Imitations of 

 black lead 

 drawings im- 

 peri'ect. 



The subject 

 may be 

 sketched with 

 a pencil imme- 

 diately on liie 

 copper. 



Wo retracing 

 itecessary. 



Tracing rag. 



iv ERCEIVING the various methods of imitating draw- 

 ings and sketches in the graphic art fall short of an accurate 

 imitation of the black-lead pencil, 1 determined on an at- 

 tempt, some years since, which, after repeated experiments, 

 1 flatter myself I have fully established. 



The manner is totally new, and solely my own invention : 

 —•by the method I adopt any artist can sketch with a black- 

 . lead pencil his subject immediately on the copper, and so 

 simple and easy is, its style, that an artist can do it with five 

 minutes study. 



By this manner, the trouble in tracing an oil paper, and 

 other retracing on the etching ground is avoided, and the 

 doubtful handlingof an etching-needle is done away:}:, as the 



*A thirdof the arch of CO°from the horizon would give 20°, and 4 

 li*W. C. ^ 



t Trans, of the See. of Arts, vol. XXVUl, p 97. The silver medal 

 aivi thirty guineas were voted to Mr. Hassell for this cominunication> 



J Tracing rag should be made of a piece of Irish linen, not too ih'ucli"' 

 vom, the sutface of which is to be rubbed with another rag dipped in 

 sweet oil, just 'sufficient to retain a small portion of vermillion or pounded 

 rt'd chalk. This must be placed with the coloured part towards th* - 

 gr««tjd of the plate, and the drawing or tracing laid upon it, which xnxe.%^ 

 be traced ver« lightly wuh a blunt point or needle, 



pencilling 



