1868.] 463 [Jackson. 



woods are pvoduced. Even bleaching salts have thus been intro- 

 duced into trees with acids to disengage the chlorine, and wood, white 

 as ivory, has been made for ornamental use. 



Perrin improved these processes and also was enabled to effect a 

 more thorough impregnation of ^vood by making a vacuum at. one end 

 of the logs while the atmospheric pressure drove the dye stuffs into the 

 wood. He was the first who introduced mordants to aid the action of 

 the dyes. He colored wood with solutions of the different madder 

 colors and fixed them Avith alum. He used logwood, Brazil wood, 

 indi;^o, nitrate and acetate of copper and verdigris, giving a great vari- 

 ety of tints to the same wood. Pyrolignite of iron, or iron liquor of the 

 calic;o printer, proved to be one of the most effective dyes and pra- 

 servatives. 



Some of the agents used in the , i^i't'servation of ivood act as fol- 

 lows: — tannin acts on the albuminous mattei's in the same way as 

 on animal tissues ; tar and creosote dissolved in pyroligneous acid are 

 eminently antiseptic; oils, fats and resins keep out humidity; sea salt 

 and chloi'ide of calcium give flexibility to wood and prevent some chemi- 

 cal changes; sulphate of coj)per acts very much like the bi-chloride of 

 mercury used by Kyan; pyrolignite of iron (Boucherie's pi'ocess) both 

 colors and conserves, the iron taking the tannin and producing a 

 violet blueish tint, while the creosote in the acid is antiseptic; chlo- 

 ride of zinc (Burnet's proces) acts like the bi-chloride of mercury 

 and is cheaper; acetate of lead tends to preserve the albumen; rosin 

 dissolved in hot oil is principally used to keep out water; a hot 

 mixture of wax and tallow is sometimes used; the wood absorbs 

 from 15 to 60 per cent, of its weight and is much improved in im- 

 perviousness to water, but wax is too costly; marine glue or shellac 

 and india rubber dissolved in coal tar are good, so far as they can 

 be made to penetrate, and effectually prevent the wood from crack- 

 ing. 



I have found that the most effective and perfect stuffing of Avood 

 can be effected by immersing it in very hot paraffine, and withdrawing 

 the air from the wood cells by the air pump and then letting on the 

 atmospheric pressure. By means of paraffine we may preserve any 

 kind of wood perfectly, and prevent its swelling or shrinking from 

 moisture or dryness. The wood may be sand-papei"ed, or pumiced 

 and polished very highly. 



Paraffine in vapor cannot be used, since the heat required to vapor- 

 ize it is too great for wood to bear without becoming brown. 



I have advised the manufacture of refrigerators with white wood 

 boards stuffed with paraffine, since paraffine will not absorb or give 

 out odors, nor will it admit moisture. Indeed, it is as its name signi- 

 fies, almost without affinities. 



