' Dxperiments on Staining Wood. 



Fieces of different kinds of wood, of considerable thicl 

 were placed in the fulphurous acid. In half an hour the 

 whole furface of them was covered with a vtllowiih fcurf, 

 rii\ ! the wood itfelf had the appearance of being charred. 

 When waihed in water, and expofed fonic hours to the open 

 air, it was obferved that the black colour had penetrated fiill 

 farther, that the interior part only retained the natural 

 colour, and that the wood was exceedingly" clofe and com- 

 pacl. After this wood had been feveral times rubbed over 

 with the oil or fpirit of turpentine, it became harder and 

 firmer, lb that it could receive the higheft polifh ; by which 

 means the colour was rendered more agreeable. This procefs 

 may be readily employed by artifts, as it is eafy, and does not 

 require much expeoce. 



V. Another black dye for ftaining wood, which fueceeds 

 extremely well, and may lead to other ufeful experiments, is 

 that formed with liver of fulphur (fulphurct of potafh) and 

 metallic folutions. As the fulphurized hydrogen gas is fo 

 fubtle that it penetrates the clofeft bodies, it might readily 

 be conjectured that it would eafily give a black colour to 

 wood, if the latter could any how be made to imbibe it with 

 a metallic folution. Pieces of different kinds of wood were 

 placed, for feveral days fucceffively, in a folution of acetite of 

 kad, and a folution of filver, copper, iron, and other metals ; 

 after which a folution of arfenical liver of fulphur was pre^ 

 pared in the following manner : One part of the arfenical 

 liver of fulphur was mixed with two parts of clear quick- 

 lime, in a porcelain veffel, over which was poured fix or 

 eight parts of boiling water. The folution was then poured 

 off, and the wood which had been impregnated with the 

 : metallic folutions being placed in it and fuffer.ed to 

 lain.feyeral days, the veffel being clofely {hut, it affumed 

 a black colour. The folution of acetite of lead produced the 

 grcak-ft effect ; that of filver next, and thofe of the other 

 dl of all. Spotted wood, and particularly that of 

 the plane, beech and peaiytree, affumed the beft colour, 



It 



