NATURE'S CRAFTSMEN 



aging a saw-mill. When making staves upon the moun- 

 tain he had frequently noted the loss of the blocks by 

 ant-cuttings. Usually the insects took hold of some 

 decayed part of the tree, but often they attacked sound 

 wood. This was the tenor of the testimony taken in 

 the mountain region near Bellwood and Altoona. The 

 most formidable case of injury — which I had not the 

 opportunity to verify — was reported by a young farmer 

 on Brush Mountain, who said that a tract of oak timber 

 eight or ten acres in extent belonging to his father had 

 been almost ruined by the black ants. This case stands 

 alone among the many reported. As a rule, the attacks 

 seem to be more annoying than injurious. One of the 

 largest proprietors of lumbering interests, especially in 

 West Virginia, has just written me that he does not 

 think the operations of ants in standing timber entail 

 serious loss. On the other hand. Professor Surface, the 

 Economic Zoologist of Pennsylvania (1906), writes me 

 that Pennsylvanicus " undoubtedly does a great deal of 

 damage to trees, logs, and timbers of buildings by 

 opening up the solid wood to contact with air and 

 moisture, thus promoting decay." 



But how stands the case with exposed structures of 

 wood? Might not such excavations as represented in 

 the section taken from the mill beam become dangerous, 

 as, for example, in railroad bridges and trestles? We 

 were then on the main line of the Pennsylvania Railroad, 

 which had not yet entered the era of stone and iron 

 bridges that now happily prevails. But the inspection 

 of many wooden trestles showed no signs of dangerous 

 impairment. However, while these facts were being 

 communicated at a meeting of the Philadelphia Academy 

 of Natural Sciences, Mr. Wilson, a well-known civil 



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