304 RESOURCES OP CALIFORNIA. 



inches deep, with a grade of 13 feet to the mile, will carry 

 about 800 inches, and such a flume built on the surface of the 

 ground will cost now at the rate of $4,000 per mile, near a 

 saw-mill. The boards are put in the flume rough, but are 

 always battened, and sometimes caulked. The cheapest flume 

 costs twice as much as the cheapest ditch of the same capacity, 

 and the repairs of a flume cost 90 per cent, more than those of 

 a ditch. The duration of a high flume is on an average 

 about six years, and of a low one, eight or ten. For the first 

 two or three years after the construction of a ditch, there is 

 much trouble from gopher holes and slides. 



The flumes in the highest portions of the Sierra, and 

 especially about Rowland Flat and La Porte, are troubled by 

 the snow, and much labor is spent on them every winter. 

 The weight of the snow is so great that after every snow- 

 storm, or while it is in progress, a man must go along and 

 clear the flume with a shovel. In cases where the flume is on 

 a hill-side, it is necessary to shovel away the snow from the 

 upper side of the flume, for the mass moves down hill with 

 tremendous weight, though with very slow motion, and no 

 flume could resist it. 



224. Iron Pipe. The use of iron pipe in the form of 

 an inverted siphon, instead of a high flume, for the purpose of 

 carrying water across ravines, has been a great improvement 

 and saving in the ditch business. Near Placerville, water is 

 carried across a depression 190 feet deep and 1,600 feet long, 

 in a pipe that cost $900, whereas a flume would have cost 

 $25,000. Not only is it cheaper, but it can be used where 

 fluming is pecuniarily impossible, as in crossing ravines 400 feet 

 deep. 



The sheet iron used in making pipe, comes in sheets two 

 feet wide and six feet long. The common sizes of pipe are 7 

 and 11 inches in diameter, made in joints two feet long. A 

 sheet makes two joints of 11 -inch pipe, and three of seven- 

 inch, and 11 joints are riveted together to make a section 20J 



