870 Transactions of tub American Institute. 



gant ; lie would therefore confine liis remarks to Lis invention as a 

 special topic. Some years ago lie was called iipou by a gentleman 

 largely connected with ship-building on the Clyde (Scotland) and 

 requested to examine into the merits of a patented process for the 

 preservation of wood. This led to a thorough investigation of all 

 processes ever proposed or used for that purpose, and after analyti- 

 cally ascertaining the reasons why some of them failed totally, others 

 succeeded partially, but none fully, he came to the conclusion, at 

 which the several si^eakers and the club generally had arrived, that 

 the only ix)licy, which promised success, was to follow in the footsteps 

 of nature ; that no treatment could succeed unless it extracted or 

 destroyed the nitrogenous substances of the wood, and filled the pores 

 in such manner as effectually to ])rotect them against the alternate 

 conditions of moisture and dryness, heat and cold. 



This Avas most perfectly done by his process. He placed the wood 

 in a tank, boiler or retort, one end of the M'ood higlier than the other ; 

 adds sufficient resin, when liquified, to cover the wood, and having 

 poured in a slight quantity of water, closes the boiler and applies 

 lieat. The first efliect is to convert the water which was poured ii:, 

 as well as that contained in the pores, into steam, which softens the 

 wood and opens the pores. Then, after the heat has risen to 275 

 degrees Fahrenheit, and the pressure to forty-four pounds per square 

 inch, the resin begins to melt and trickles slowly down, its level rais- 

 ing as more and more is melted, and as the level of liquid resin raises 

 it enters into the pores of the wood from below, displacing and dri- 

 ving out the steam above. At the same time the great heat utterly 

 destroys the nitrogenous or albuminous principles of the wood, and 

 after a few hours the wood is thoroughly impregnated. 



He then exhibited a very beautiful and extensive array of speci- 

 mens, among them large sticks of hickory, maple, birch, soft pine, 

 spruce, hemlock, etc. All the specimens were thoroughly impreg- 

 nated in all parts, and Mr. Heinemann stated that he could, with 

 equal facility, saturate the pores of the longest and thickest sticks or 

 trees. 



The qualities of these woods are wonderfully improved, the treat- 

 ment having increased their hardness, density and strength, and 

 greatly heautijied them, making them to resemble rosewood, ebony, 

 black walnut and mahogany, for which they will most pi'obably 

 become valuable substitutes. It makes the wood perfectly imper- 

 vious to water ; one piece which had been immersed for forty -two 



