1 't !■ WATER-TKANSPOKT. 



has been ensured, and everything is ready at the timber-depots 

 below for the reception of the wood, the first sweep of wood may 

 be sent down at the right time. A careful choice of the 

 latter is of great importance, and is a matter of days, even of 

 hours. A commencement should ahvays be made in the 

 most remote and weakest of the subsidiary streams, so that 

 the sweep of timber passing through it may come down as 

 soon as possible into the main stream, where progress is not so 

 dependent on the period of the highest floods. Hence, a dis- 

 tinction 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 already being done in the Alps. In 

 other localities, as in the Palatinate, only subsidiary sweeps are 

 attempted, the wood being floated right up to a railway. 



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

 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 consideration 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 the residue of the water may 

 have its eff'ect 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 water 

 at a time than is absolutely necessary. He will easily learn by 

 experience for how many miles down the water from his reservoir 

 can ilood the floating-channel sufliciently, and how long the 

 sluice-gates should be kept open to ensure a proper supply. 



