and the Application of it to jlained Wood. 235 



litharge would be dlflblved, and the varnifli become too 

 thick. 



The compofition of amber varnifh confifts of half a pound 

 of melted or roafted amber, one poimd and a half of linfeed- 

 oil varnifh, and two pounds of turpentine oil. The amber 

 aad linfeed-oil vamiOi are to be mixed together in a deep 

 caft-iron pan, of fucli a fize as to be only one-third full, and 

 to be kept over a flow fire till the amber is diOolved, which 

 may be known by its fwclling up : the operator, therefore, 

 muft have at hand a large copper or iron veflel, that the var- 

 nifh may be held over it in cafe it fliould, rife above the fides 

 of the pan, and to prevent the lols that v.ould thereby be 

 occafioned. When the varnifli is difiblvcd, the pan mutt be 

 taken from the fire; and when the mixture has cooled, the 

 turpentine oil is to be poured into it, continually ftlrring it. 

 Then let it ftand fome time, that the eoarfe undilTolved par- 

 ticles may dcpofit themfelves at the bottom; after which 

 pour off the clear varnifli, and, having (trained it through a 

 piece of linen, put it into bottjes for ufe. 



In boiling the varnifh, care muft be taken that it may not 

 boil over or catch fire. Should this happen to be the cafe, 

 it muft not be extinguiflied by water ; for this mode would 

 occafion fuch a fputtering, that the operator would be iti 

 danger of having his face befpattered with the boiling varnifh. 

 Tiie befl method, therefore, is to cover the vefiTel in fuch a 

 manner as to exclude the air, and with any thing that may 

 be at hand, fuch as a piece of wood, plate of iron, or any- 

 thing elfe that may cover the vcfl'el and cxtinguifn the flame, 



I. Iron Slain. 



Eight ounces of iron-filings and thirty-two ounces of 

 common aquafortis. The aquafortis muft firft be mixed 

 with fixteen ounces of water in a (lone jar, and then a few 

 of the filings are to be added, and well ftirred round with an 

 iron or wooden fpatula. This preparation nuift be made in 

 a chimney, bccaufe the folution is attended with heat, effer- 

 vefcence, and the difcngagement of noxious vapours : it is of 

 importance, alio, that the jar fliould be of fuch a fize as to 

 prevent the matter from running over. After tlic greater part 

 11 h 3 of 



