--------+---------+-----------+-----------+-------------+-------+-------- Number | Total | Average | Estimated |Corresponding| Total |Per Cent of |Weight of| Weight of | Weight of | Size. | Weight| of Stones | Portion.| Stones. | Smallest | Millimeters.| of |Total in | Grams. |Milligrams.| Stones. | |Stones |Weight Portion.| | |Milligrams.| |Smaller|Smaller (Largest| | | | | than | than Selected| | | | | this | this Stones.)| | | | | Size. | Size. --------+---------+-----------+-----------+-------------+-------+-------- | .... | .... | .... | .... |11,870 |=100= 10 | 3,320 | 332,000 | 250,000 | =56= | 8,550 | =72= 10 | 1,930 | 193,000 | 165,000 | =49= | 6,620 | =56= 10 | 1,380 | 138,000 | 124,000 | =45= | 5,240 | =44= 20 | 2,200 | 110,000 | 93,000 | =41= | 3,040 | =26= 20 | 1,520 | 76,000 | 64,000 | =36= | 1,520 | =13= 20 | 1,000 | 50,000 | 36,000 | =30= | 520 | =4.4= 20 | 460 | 23,000 | 10,000 | =20= | 60 | =.5= 10 | 40 | 4,000 | 2,000 | =11= | 20 | =.2= Dust | 20 | .... | .... | .... | .... | .... --------+---------+-----------+-----------+-------------+-------+-------- The weight of the smallest stones in a portion given in the fourth column is estimated in general as about half-way between the average weight of all the stones in that portion and the average weight of the stones in the next finer portion. The final results are shown by the figures in full-faced type in the last and third from the last columns. By plotting these figures we find that 10 per cent of the stones are less than 35 millimeters in diameter, and 60 per cent are less than 51 millimeters. The “uniformity coefficient,” as described below, is the ratios of these numbers, or 1.46, while the “effective size” is 35 millimeters. II. ANALYSIS OF A SAND BY MEANS OF SIEVES. A portion of the sample was dried in a porcelain dish in an air-bath. Weight dry, 110.9 grams. It was put into a series of sieves in a mechanical shaker, and given one hundred turns (equal to about seven hundred single shakes). The sieves were then taken apart, and the portion passing the finest sieve weighed. After noting the weight, the sand remaining on the finest sieve, but passing all the coarser sieves, was added to the first and again weighed, this process being repeated until all the sample was upon the scale, weighing 110.7 grams, showing a loss by handling of only 0.2 gram. The figures were as follows: