"Experiments on Staining Wood. 57 



Succeeds when the fpirit of wine has been long boiled over a 

 flow fire till it is almoft evaporated. The piece of wood ap- 

 pears then of a dark red colour, which is improved if the 

 wood be wafhed in pure fpirit of wine. But the colour is 

 never fo bright as that produced by means of an oil. 



II. Gamboge with fpirit of wine gave to wood in this 

 manner a yellow, and gamboge and dragon's blood a yel- 

 lowifh red, colour. 



3. Experiment with IVax. 

 White wood boiled in fpirit of wine, to which, when it 

 began to boil, wax was added, could not be made to affume 

 the green or the red dye, even in its fmall crofs veins, which 

 were exceedingly porous. 



4. Experiments with dijfolved Salts and Metals. 



The following experiments with thefe fubftances, which 

 have already been defcribed byMacquer, feemed to be moft 

 fuccefsful. 



Exp. I. Afolution of common alum (fulphat of alumine) 

 penetrates exceedingly well into wood which has been di- 

 gefted in it ; fo that hopes may be entertained of fome thing 

 being effected by it, as the white colour of every kind of 

 wood becomes whiter by folutions of faline fubftances : this 

 may be of great ufe to artifts. 



II. Wood foaked in a folution of gold affumed a red co- 

 lour, but the inner part was only of a yellowifh red. 



III. Diftilled verdigris diffolved in vinegar ftained wood 

 green, but the colour could never be brought to a grafs 

 green. 



IV. Wood which has lain a long time under water be- 

 comes black, as experience fhews, and looks as if charred. 

 It, however, lofes none of its toughnefs or compa&nefs ; 

 and many trees dug up in Holland from the turf earth are 

 employed there for fliip-building. This effe& of the fulphurio 

 acid on wood gave occafion to the following experiment. 



Pieces 



