FLOATING. 403 



not so dependent on the period of the highest floods. Hence, 

 a distinction may be made between subsidiary sweeps of 

 timber and the principal sweeps. 



Wherever the cost and difficulty of subsidiary sweeps is out 

 of proportion to their utility, attempts should be made to 

 substitute sledging for floating, as is being done already in 

 the Alps. In other localities, as in the Palatinate, only sub- 

 sidiary sweeps are attempted, the wood being floated right up 

 to a railway. 



Before the sluice-gates are opened, and floating the sub- 

 sidiary sweeps is begun, the quantity of the wood to be 

 launched should be proportioned to the quantity of water in 

 the reservoir and the strength of the boom, otherwise there 

 will be danger of the tail of the sweep being left stranded, or 

 of the boom being broken, if a flood should occur. Due con- 

 sideration having been given to these points, the sluice-gates 

 are opened, and after the preliminary flooding, the strength 

 of which depends on the amount of impediments there may be 

 in the floating-channel, the floating-gang commence throwing 

 the wood into the stream. As soon as most of the water has 

 left the reservoir, the gang stop launching the wood, so that 

 tin- residue of the water may have its effect on the tail of the 

 sweep and carry it away. As soon as the reservoir is empty, 

 the dam is closed again in order that a fresh supply of water 

 may be collected. 



In the case of floating-channels which cannot be flooded by 

 a considerable body of water, but only by a moderate supply 

 from fear of damage to their banks, it is the duty of the forest 

 guard in charge of the reservoir to be careful not to supply 

 more w r ater at a time than is absolutely necessary. He will 

 learn easily by experience for how many miles down the water 

 from his reservoir can flood the floating-channel sufficiently, 

 and how long the sluice-gates should be kept open to ensure a 

 proper supply. 



The wood now is carried down by the flood from the reservoir, 

 and the best, smoothest, well-dried w r ood keeps at the head of 

 the sweep, whilst inferior knotty wood and hea\'y butts gradually 

 la 14 behind to form its tail. However well the floating-channel 

 may he regulated, hindrances will arise whenever the wood 



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