-------+------------+--------+--------- | Size of | | | Separation |Quantity|Per Cent Sieve | of this | of Sand| of Marked.| Sieve. |Passing.| Total |Millimeters.|Grams. | Weight. -------+------------+--------+--------- 190 | =.105= | .5 | =.5= 140 | =.135= | 1.3 | =1.2= 100 | =.182= | 4.1 | =3.7= 60 | =.320= | 23.2 | =21.0= 40 | =.46= | 56.7 | =51.2= 20 | =.93= | 89.1 | =80.5= 10 | =2.04= | 104.6 | =94.3= 6 | =3.90= | 110.7 | =100.0= -------+------------+--------+-------- Plotting the figures in heavy-faced type, we find from the curve that 10 and 60 per cent respectively are finer than .25 and .62 millimeter, and we have for effective size, as described above, .25, and for uniformity coefficient 2.5. III. ANALYSIS OF A FINE MATERIAL WITH ELUTRIATION. The entire sample, 74 grams, was taken for analysis. The sieves used were not the same as those in the previous analysis, and instead of mixing the various portions on the scale they were separately weighed. The siftings were as follows: Remaining on sieve marked 10, above 2.2 millimeters 1.5 grams Remaining on sieve marked 20, above .98 millimeters 7.0 grams Remaining on sieve marked 40, above .46 millimeters 22.0 grams Remaining on sieve marked 70, above .24 millimeters 20.2 grams Remaining on sieve marked 140, above .13 millimeters 9.2 grams Passing sieve 140, below .13 millimeters 14.1 grams The 14.1 grams passing the 140 sieve were thoroughly mixed, and one third, 4.7 grams, taken for analysis. After ignition just below a red heat in a radiator, the weight was diminished by 0.47 gram. The portion above .08 millimeter and between .04 and .08 millimeter, separated as described above, weighed respectively 1.27 and 1.71 grams, and the portion below .04 millimeter was estimated by difference [4.7 - (0.47 + 1.27 + 1.71)] to be 1.25 grams. Multiplying these quantities by 3, we obtain the corresponding quantities for the entire sample, and the calculation of quantities finer than the various sizes can be made as follows: