384 



WATER-TKANSPOKT. 



<,a-eat pressure, as for instance \Yliere numbers of saw-mill butts 

 are bein<? floated, or the floating,' wood is beinjj^ driven from the 

 main-stream into a bifurcation, a fixed boom 'tig. S'io) should be 

 constructed. In this case, piles {in m) are driven into the bed 

 of the stream and are supported by props (ss). The logs forming 

 the boom are then attached to these piles and close the stream. 



Fio. 225. 



One row of logs is often insuflicient, and then two or more logs 

 are fastened together and placed in front of the piles. Such 

 booms will not, however, stop waterlogged wood ; when there is 

 much of this, a more complete boom is rerjuivod, the construc- 

 tion of which will be described further on. 



V. Acccssihiliti/ of the Banks of the Stream. 



Accessibility of the l)anks is another necessity whenever 

 a stream is used for floating timber. The water must be 

 accessible at least from one of the banks by a good foot-path, so 

 that the workmen may bo able to fasten logs to the shore, push 



