NORTH DAKOTA PAINT TESTS 185 



much better results had they been painted with paints properly 

 reduced to suit the nature of the wood. This treatment seems 

 to have been overlooked in the North Dakota tests, and the 

 painting of the hard pine boards was done with the same con- 

 sistency of mixtures and the same reductions as upon soft pine. 

 Scaling of course resulted. One of the chief purposes of the 

 fences, however, was to study the different types of wood, and 

 compliance with this desire resulted in the bad conditions herein 

 noted. It has been shown in many other field tests that adher- 

 ence of paints to hard wood surfaces can be obtained only by 



Pine Weatherboarding Showing Knots and Grain 



causing the priming coat to become amalgamated with the 

 woody fibre, by the use of a large percentage of volatile diluent 

 turpentine, benzole, asphaltum spirits, etc., to secure penetra- 

 tion. If such treatment is omitted, failure soon results, as was 

 evidenced by the uniformly bad conditions presented by the 

 paints on the hard pine panels. 



" During July, 1908, a violent hailstorm occurred in Fargo, 

 and left its impression on nearly every wooden structure; in 

 many cases deep dents being made into the wood. The west 

 side of the test fences, which received the most injury from this 

 storm, was covered with these dents over almost its entire surface, 

 causing cracks in the form of concentric rings to appear on the 



