FLOATING. 399 



boom ; or the risk cannot be incurred, in the case of numbers 

 of saw-mills situated along a stream, of entrusting the supply 

 of the thousands of logs they require for their annual work to 

 one boom only, which is always liable to be broken. In such 

 cases, subsidiary booms are used in order to ensure a supply 

 of wood for all the saw-mills. 



For this purpose narrow parts of the stream are selected, 

 confined on either side by rocks, and there booms with move- 

 able gratings are erected, from which the wood can be again 

 despatched down-stream in small sweeps to the different saw- 

 mills or timber depots. 



Not unfrequently a stream is broken-up by booms at not 

 very long intervals ; this is either for charcoal-burning, in 

 order to land the wood required where permanent charcoal- 

 kilns are maintained ; or each forest-owner or principal wood- 

 merchant has his own boom, in order to collect his own wood 

 and float it separately from that of other owners to the principal 

 boom ; or the saw-mills situated along the stream have each 

 its special boom, provided with passages to allow extraneous 

 wood to pass through them. 



Subsidiary booms are erected sometimes in strong streams 

 below the principal boom, where, owing to occasional floods, 

 there may be danger of the latter breaking. Whenever floating 

 timber is rafted, or passed in lines of logs across a lake, most 

 of the water-logged wood would enter the lake and sink to the 

 bottom without possibility of recovery, were not a boom 

 stationed at the point where the stream used for floating 

 passes into the lake. 



4. Method employed in Floating Wood. 



(a) Season for Floating. The more quickly a sweep of 

 wood is floated and reaches its destination, the better is the 

 business of floating conducted. For this purpose, a steady 

 and ample supply of water is necessary. The melting of the 

 mountain snow in spring brings most water into European 

 streams, and spring is therefore the chief season in Europe 

 for floating timber. At this season all the brooks and springs 

 which flow into the floating-channel are swiftest and most 



