for the Liquefaction of Copal and Amber. \yj 



knife terminating in an elbow is introduced under the tube, 

 and moved in such a manner as to cause the liquefied part of 

 the copal to fall down into the water, and to bring it under 

 the solid form towards the edge of the capsule. When the 

 operation is finished, the copal is spread out on dry linen 

 cloths, or on unsized paper, to dry ; it is then piled up and 

 exposed to a gentle heat, to deprive it of all its humidity. 



While the copal is falling down there is separated a very- 

 small portion of oil, which remains fluid after the opera- 

 lion. It floats on the water as well as the copal, and gives 

 to the latter a greasy appearance. But when the tube is of 

 sufficient length there will be no necessity for immersing the 

 end of it in the water, or even for receiving the matter in the 

 \\ atcr ; but, in this case, a kind of smoke will escape, which 

 may be offensive to the artist. The essential point is to gra- 

 duate the fire in such a manner as not to alter the colour of 

 the copal. When a very thick smoke issues through the 

 lower aperture of the tube ; when the latter is very red ; and 

 .when the drops which fall into the water rise into bladders 

 and form small explosions, there is reason to conclude that 

 .the. fire is too violent. 



I have succeeded in composing varnish with fat oil, in the 

 same operation, by substituting for the water drying oil in a 

 state of ebullition, and maintaining it in that state by means 

 of a mass of very hot iron, which served it as a supporter. 

 The mixture of the liquefied matter is facilitated by means 

 of a spatula, with a knee at the extremity ; and the boiling 

 -essence is afterwards added. The inconvenience of placing 

 under the apparatus a volatile and highly inflammable oil 

 may be readily conceived. 



This new mean enables the artist to compose a very du- 

 rable varnish, very little coloured, and superior to copal var- 

 nish composed with drying oil, as the composition of the 

 latter requires processes which alter the essential qualities of 

 the substances that form the basis of it. 



For operations on a larger scale the dimensions of the fur- 

 nace may be changed ; but in this case it will be proper to 

 elevate the fire-place, properly so called, on a kind of iron 

 tripod, as represented at G, fig. 4, in order that the work- 

 man may be more at his ease. I must however always insist 

 on the advantage of employing, in the process, doses of only 

 four and six ounces. 



The valuable advantages which accompany this new me- 

 thod will be perceived when a trial has been made of the var- 

 nish composed with essence of turpentine, which results 



from 



