VARNISHING. §41 



less danger of being scorched, and at the same time 

 the varnish is more beautiful. They should be 

 melted in an iron pot over the fire : they are in a 

 proper state for receiving the oil when they give 

 no resistance to the iron spatula, and when they 

 run off from it drop by drop. 



To make oil varnish, pour lour, six, or eight 

 ounces of drying-oil among sixteen ounces of 

 melted copal, or amber, by little and little, con- 

 stantly stirring tlie ingredients at the same time, 

 with the spatula. When the oil is well mixed with 

 the copal or amber, take it off the fire ; and when 

 it is pretty cool, pour in sixteen ounces of the 

 essence of Venice turpentine. After the varnish 

 is made, it should be passed through a linen cloth. 



Oil varnishes become thick by keeping; but 

 when they are to be used, it is only necessary to 

 pour in a little Venice turpentine, and to put them 

 a little on the fire. Less turpentine is necessary in 

 summer than in the winter : too much oil hinders 

 the varnish from drying; but when too little is 

 used, it cracks, and does not spread properly. 



Black Varnish for Coaches and Iron- Work. 



This varnish is composed of asphaltum, resin, 

 and amber, melted separately, and afterwards 

 mixed; the oil is then added, and afterwards the 

 turpentine, as directed above. The usual propor- 

 tions are, twelve ounces of amber, two of resin, two 

 of asphaltum, six of oil, and twelve of turpentine. 



A Varnish for rendering Silk Water and Air-ttghl. 



To render the linseed-oil drying, boil it with 

 two ounces of sugar of lead, and three ounces of 



VOL. II. R 



