2&6 ILLINOIS STATE ACADEMY OF SCIENCE 



The Baltimore and Ohio Kailroad gives the results ob- 

 tained from three hundred red oak ties treated with 

 sodium fluoride and placed in track at Herrin Bun*** in 

 1914. To date, two of these ties, or 0.6 per cent of the 

 total number placed in track, have been removed because 

 of decay, and five, or 1.7 per cent, because of other 

 reasons. This makes a total of seven ties of the three 

 hundred placed in 1914 that have been removed. These 

 ties received 0.41 pounds of sodium fluoride per cubic 

 foot. 



In 1921 more than three-fourths *of the timber pre- 

 serving plants in the United States were in the hands 

 of either commercial or private companies, while the 

 rest were in the hands of the railroads. As the railroads 

 use a large part of the treated wood of the country much 

 of the treating is done by contract. Because of this it is 

 necessary to have a penetration test for the preservative 

 in order to prove the depth of the treatment. 



At the present time nearly all of timber preserved is 

 treated with either cresote or zinc chloride or a mixture 

 of the two. Sodium fluoride is coming into more general 

 favor because it seems to have as good preserving quali- 

 ties and is much less corrosive .than zinc chloride which 

 gives a large overhead in plant equipment. 



The progress of sodium fluoride treatment has been re- 

 tarded by the lack of a satisfactory penetration test and 

 a simple, accurate and rapid method of analysis. A test 

 for sodium fluoride penetration was presented to the 

 American Wood-Preservers' Association at their meet- 

 ing in January, 1923, but this test has not proved to be en- 

 tirely satisfactory as it calls for absolute alcohol, which 

 is not a general laboratory reagent in a commercial 

 laboratory. The solutions used are : 



1. Three per cent solution of ferric chloride in abso- 

 lute alcohol. 



2. Three per cent solution of ammonium thiocyanate 

 in absolute alcohol. 



The surface of the wood to be tested is sprayed evenly 

 with the solution of ferric chloride, and dried and then 



*** Baltimore and Ohio Railroad, Report of Experimental Ties, 1922, 

 page A2. 



