abstracts: zoology and technology 445 



are rather small, though some of the erect chilostomes form bushy colonies 

 several inches in height. 



The author calls attention to the fact that while the Bryozoa yield 

 no useful products and thus have no direct value in commerce, they, 

 like most other small marine animals, play a part in furnishing food for 

 fishes. He has seen large nodules of Schizoporella and Smittia taken 

 from the stomachs of sharks, while among the edible fishes the examina- 

 tion of such species as the cunner and tautog indicates that the various 

 Bryozoa often form no inconsiderable part of the diet. 



To this paper is appended a bibliography of 73 titles. 



Ethel M. Smith. 



TECHNOLOGY. — The preservation of mine timbers. E. W. Peters. 

 Forest Service Bulletin 107. Pp. 27, with plates and diagrams. 

 1912. 



In mining operations the cost of timber is a factor of much impor- 

 tance. In 1907, $10,000,000 was spent for round mine props alone, 

 while additional outlay was necessary for lagging, planking, and other 

 forms of lumber extensively used in mines. The life of mine timbers is 

 in many cases very short, and as the supply of the better grades becomes 

 depleted the less durable kinds must be used. 



Altho decay, which in general is the agency most destructive to timber 

 used in mines, may be retarded by peeling and seasoning, treatment 

 with a suitable preservative is more effective. 



The average life of green, unpeeled, and untreated loblolly pine gang- 

 way sets, under the conditions studied, was less than one and one-half 

 years. Brush treatments with creosote and carbolineum increased this 

 to three and four years, while impregnation with zinc chloride and 

 creosote left from 70 to 90 per cent of the timbers sound at the end of 

 four years. 



Brush treatments are economical when the amount of timber to be 

 treated will not warrant the erection of a small open-tank or pressure 

 plant, or when only a short increase in service is required. The open- 

 tank process is adapted to the treatment of small quantities of easily 

 impregnated timber. When a large amount of material is to be treated, 

 a pressure process should be used. Mine timbers impregnated with 

 zinc chloride and creosote oils have shown the best results. 



Findley Burns. 



