298 ILLINOIS STATE ACADEMY OF SCIENCE 



The reasons that the test is needed are to check up 

 on the treatment and to know that the preservative is 

 penetrating the wood. In the railroad plants and the 

 private plants it is used to show that they are forcing 

 the preservative into the wood, while in the commercial 

 plants it is called for in their contract and treating speci- 

 fications. It helps to determine what life to expect from 

 a stick of timber. If the preservative has gone to the 

 center of the wood it can be expected to give a longer life 

 than if the preservative had merely coated the wood. If 

 the preservative has merely coated the wood, many bac- 

 teria will soon get into the wood where it is scarred in 

 handling and destroy it from the center. 



The color contrast in this test is greater than in any 

 of the other tests. Wood ranges from white in pine, to 

 red in cedar and a dark brown in walnut. Red will not 

 show up as well with any of these colors as will a dark 

 blue. 



In conclusion, the advantages of the above test are : 



1. It is the only permanent test as yet advanced. 



2. It shows a much better color contrast than any 

 other test. 



3. The dividing line is permanent arid sharp. 



4. It is much easier to make than the other test be- 

 cause of the ease in making up solutions. 



5. Solutions are much more stable. 



6. Materials are much cheaper. 



