PAPERS OX GEOGRAPHY AND GEOLOGY 389 



ing steam consumed, thermometers, pressure gauges, and 

 the like. By means of these ingenious devices a complete 

 record of temperature and processes is made on circular 

 discs from day to day and filed away for future refer- 

 ence. (By courtesy of Mr. Shinn, Superintendent of the 

 Galesburg plant, I am able to exhibit a card showing 

 temperature and pressure record.) Adjacent to the main 

 plant is to be found huge tanks having a capacity, in case 

 of the Galesburg plant, of one half million gallons each. 

 In addition, the Galesburg plant has a mixing tank into 

 which, creosote, zinc chloride, etc. may be pumped in de- 

 sired proportions. The treating fluids are obtained from 

 standard dealers, such as The Tar-Via Company. Much 

 of the creosote has been produced as a bi-product in 

 Germany. 



Timber to be treated is seasoned by piling in the open 

 for about one year. The ties are stacked cob-house fash- 

 ion so that air will circulate freely and rain water will 

 run off readily. No successful method of treating green 

 timber has yet been devised. The tie is next placed on 

 low cars or cradles in compact form so that the encircling 

 hoops when packed full will fill approximately the bore of 

 the retort. A series of the cradles are coupled together 

 and drawn into the treating chamber by a wire cable, the 

 power being supplied from winding a drum. The retort 

 is closed, and steam is admitted for a period of one or 

 more hours according to the size and nature of the mater- 

 ial treated. This process effects an even distribution of 

 moisture and ensures uniform drying, while excess water 

 which accumulates is forced into outside tanks, since the 

 pressure in the retort is greater than in the tanks. 



The second step in the treatment is the creation of a 

 partial vacuum. This is a real drying process, as evap- 

 oration goes on rapidly where a vacuum of twenty inches 

 or more is maintained. The third step is the admission 

 of creosote oil, at first without pressure : afterward the 

 pressure is brought up to 175 pounds or more ; later the 

 oil is forced back to the working tanks from the retort by 

 compressed air, the door is opened and the load drawn. 

 The wood has absorbed about 12 pounds of creosote oil 

 per cubic foot and has been made so heavy that it will 



