State Mvsevm of Natural History. 93 



I built some extensive trestles. This was in 1873. Before doing so 

 I examined a number of trestles near Cleveland, Ohio, built of 10 by 

 12 or 12 by 12 timbers, the life of which did not exceed seven or eight 

 years. In examining them I found that while the large timbers were 

 sound upon the outsidcj internally they were all decayed. The small 

 timbers, 6 by 8, used for braces and of the same kind of wood, were 

 sound. The small size enabled them to season in the structure. This was 

 an important fact, so I made all of my timbers small, using more of 

 them to give the proper factor of safety. One of those trestles is in 

 use now, 1889. In this case one of the three essentials requisite for 

 the growth of fungi was eliminated, namely, the moisture in the 

 interior. Decay could not, therefore, take place. The first step to be 

 taken in this important matter has already been, in great measure, 

 done by you, namely, the collection of specimens and the classifica- 

 tion of the species of fungi. This, supplemented by a series of 

 specimens showing how the wood is destroyed, would form the basis 

 of one of the most important and economic departments of the State 

 Museum. The second step would be the dissemination of this 

 knowledge to the railroad companies and other consumers of wood. 



Yours truly. 



P. H. DUDLEY. 



