388 ILLINOIS STATE ACADEMY OF SCIENCE 



One of the oldest examples of creosoting timber under 

 conditions similar to the present practice is that of the 

 New Orleans and North Eastern Railroad across Lake 

 Pontchartrain, 5.82 miles in extent. The piling of yellow 

 pine, having not less than 12 inches of heartwood at the 

 head, were treated with from 10 to 12 pounds of creosote 

 per cubic foot at a temperature of 175 degrees under a 

 pressure of 150 pounds per square inch after steaming 

 and vacuum treatment. A report of the Interstate Com- 

 merce Commission Valuation Division Engineer in 1918 

 makes the following comment, "A very remarkable state 

 of preservation — The original timber in good condition 

 and apparently carefully selected and well creosoted — 

 Estimate remaining service life of this trestle thirty-five 

 years". These pilings had already had a life of thirty- 

 five years, making a total expected life of the trestle sev- 

 enty years. 



In order to understand what has happened to the tie 

 or pile when treated according to the specifications 

 sketched above, a description of an up-to-date plant and 

 processes used, follows. The main features of a modern 

 wood preserving plant are, first, the ten or twelve huge 

 cylinders, 6 or 7 feet in diameter and 120 feet to 140 feet 

 long. These retorts are mounted on heavy concrete 

 bases which are not continuous but allow more or less 

 access below the retorts. There are doors at one or both 

 ends, which, after the admission of timber to be treated, 

 are closed by fifty large steel eye bolts. Tracks extend- 

 ing from the storage yards approach the entrance to 

 each retort, where a gap of about 8 feet is bridged by a 

 movable car in a pit. This car bears a section of track, 

 continued in a well at the bottom of the retort. When 

 the door of the retort is to be opened, the carriage bear- 

 ing a section of the track is removed, allowing it to swing 

 open readily. The well contains pipe connections to tanks 

 of treating fluids, air compressors, steam pipes, etc. The 

 engine room, which contains all necessary pumps and 

 generating machinery, is located in an adjoining room on 

 re-enforced concrete foundations. One of the most in- 

 teresting of its varied equipment is an elaborate system 

 of automatic recording apparatus, a steam meter show- 



