FLOATING AND RAFTING 359 



An interesting example of a device of this sort was the log 

 carrier and sluice constructed some years ago in the Nipissing 

 district, Ontario, Canada, to divert logs from the headwaters of 

 the Muskoka River to those of the Trent River. 



The logs were first transported up a log carrier 300 feet long 

 to a reservoir 80 feet long, 7 feet wide and 8 feet deep, located 

 40 feet above the initial level. A 450-horse-power engine fur- 

 nished power for the jack works at the reservoir, and also for a 

 set of centrifugal pumps with a capacity of 20,000 gallons per 

 minute, which provided water for the reservoir, and for a log 

 sluice which was 3000 feet long and had a 4.5 per cent grade. 

 The logs as they reached the foot of the sluice were transported 

 by a log carrier up a 100-foot rise to a lake f-mile distant, where 

 they were placed in a boom and towed to the head of the river 

 down which they were driven. The second carrier consisted of 

 eight sections, each with a massive jack works driven by rope 

 transmission from a 400-horse-power horizontal water wheel 

 located near the center of the haul-up. Water for power pur- 

 poses was brought in a flume from the terminus of the carrier. 

 The conveyor chains were made with i-inch round links and 

 had log seats at intervals of 8 feet. The capacity of the carrier 

 was 10,000 logs in twenty-two hours. 



IMPROVEMENT OF THE STREAM BED AND BANKS 



Before a stream can be driven it must be cleared of fallen 

 timber, snags and boulders. The 

 former is often cut into short 

 lengths with an ax and allowed to 

 drift downstream, or is hauled out 

 on the banks. Snags, rocks and 

 similar obstructions are removed 

 with dynamite. This work is 

 done in the summer and early 

 fall when the water is low. 



Pier Dams and Abutments.— ^ig- 104. - An Abutment for the 



-r^. ■, -11 Protection of Stream Banks. 



rier dams are cribwork structures 



used to narrow the channel of a stream, guide logs past rocks 



