520 TRA'TSACTIONS OP THE AMERICAN INSTITUTE, 



Bitumen is largely used in the preservation of iron. He thought 

 the effect of using bitumen at a temperature of from 300 deg. to 

 350 deg. would be better than applying it cold. From the un- 

 qualified endorsement of the creosoting material over all others 

 by the most eminent engineers and chemists in England and 

 Scotland, where it has been largely used in dock, bridge, rail- 

 road and many other kinds of timber, with no known case of 

 failure, he was inclined to give it the preference, and has been 

 applying it to plank for Mr. Lane, Engineer of the Brooklyn 

 Water Works. He could supply the carbonic acid and oil com- 

 bined at seven cents per gallon. The process of application he 

 stated was as follows : 



1st. Prepare a strong iron cylinder and place the wood in it, 

 exhaust the air by an air pump until a vacuum is created equal 

 to about 12 lbs. to the square inch, the cylinder is then filled 

 with creosote under pressure of about 150 lbs. to the square inch ; 

 the timber is then removed fit for use. 



Second process is by placing the timber in a drying house, and 

 passing the products of combustion through it, thereby not only 

 drying the wood but also impregnating it with the volatile oil 

 and creosote contained in the fuel used to heat the house. The 

 wood is then placed in a tank containing hot creosote, remaining 

 until thoroughly impregnated. 



The Chairman inquired if there was any likelihood of procuring 

 creosote at a less price than 7 cents a gallon? 



Mr. Johnson said it was more likely to be higher. The mode 

 of obtaining creosote is by obtaining it from coal tar. Crude 

 coal oil is worth about 30 cents a gallon. 



Mr. Veeder stated that in the manufacture of coke all the pro- 

 ducts had been used up except the coke itself. 



Mr. Garvey said that the object of lighting chips around wood 

 was to produce creosote and pyroligneous acid. In manufactur- 

 ing coke all that was necessary was to drive off the light volatile 

 matter. If you continue the driving off of .the volatile matter 

 you leave nothing but carbon. Soft coke is the best for gene- 

 rating steam, and is coke not entirely deprived of volatile mat- 

 ter. 



Mr. Stetson said that the mere steaming of wood seemed to 

 destroy its life — its character ; also, that mere mechanical pres- 

 sure was a great means of changing the character of timber. 



Mr. Johnson presented specimens of timber, one from Stuart's 



