 | Augustus Jesse Bowie - 1878 - 108 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far, experience shows square block riffles to be the best...set with them require steeper grades and more water than those arranged with blocks. As a matter of convenience and economy, block riffles should be used... | |
 | California. Legislature - 1883 - 497 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far, experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steepergrades and more water... | |
 | Augustus Jesse Bowie (Jr) - 1885 - 352 strani
...inches deep, set on end in rows across the sluice, with each row separated by a space of i to i^£ inches. They are kept in position by riffle strips,...character and quantity of the gravel, and the amount of water. The larger the amount of water (on the same grade) in proportion to that of gravel, the less... | |
 | Augustus Jesse Bowie - 1885 - 360 strani
...heads of sluices, are : Ist. The cross riffle which they make is not excelled by any other form. t 2d. Their cheapness under ordinary conditions of timber...character and quantity of the gravel, and the amount of water. The larger the amount of water (on the same grade) in proportion to that of gravel, the less... | |
 | Augustus Jesse Bowie - 1885 - 364 strani
...Killlrs.—The advantages afforded by blocks, which should always be used at the heads of sluices, are : 1st. The cross riffle which they make is not excelled by...them require steeper grades and more water. Life of Blocks.—The life of a block depends on the quality of the wood, the grade, the character and quantity... | |
 | 1882 - 532 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far. experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steeper grades and more... | |
 | California, California. Legislature - 1883 - 994 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far. experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steeper grades and more... | |
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The cross riffle which they make is not excelled by any other form. 2d. Their cheapness under ordinary conditions of timber supply. 3d. The convenience of cleaning up, which can be quickly and cheaply done. This last circumstance is of especial importance,... 