Table III.—Showing Measured Voids in Sand from Different Localities.
| Locality. | Authority. | Percent Voids. | Remarks. |
| Ohio River | W. M. Hall | 31 | Washed |
| Sandusky, O. | C. E. Sherman | 40 | Lake |
| Franklin Co., O. | C. E. Sherman | 40 | Bank |
| Sandusky Bay, O. | S. B. Newberry | 32.3 | ...... |
| St. Louis, Mo. | H. H. Henby | 34.3 | Miss. River |
| Sault Ste. Marie | H. von Schon | 41.7 | River |
| Chicago, Ill. | H. P. Broadman | 34 to 40 | ...... |
| Philadelphia, Pa | 39 | Del. River |
| Mass. Coast | 31 to 34 | ...... |
| Boston, Mass | Geo. Kimball | 33 | Clean |
| Cow Bay, L. I. | Myron S. Falk | 40½ | ...... |
| Little Falls, N. J. | W. B. Fuller | 45.6 | ...... |
| Canton, Ill. | G. W. Chandler | 30 | Clean |
Voids in Broken Stone and Gravel.—The percentage of voids in broken stone varies with the nature of the stone: whether it is broken by hand or by crushers; with the kind of crusher used, and upon whether it is screened or crusher-run product. The voids in broken stone seldom exceed 52 per cent. even when the fragments are of uniform size and the stone is shoveled loose into the measuring box. The following records of actual determinations of voids in broken stone cover a sufficiently wide range of conditions to show about the limits of variation.
The following are results of tests made by Mr. A. N. Johnson, State Engineer of Illinois, to determine the variation in voids in crushed stone due to variation in size and to method of loading into the measuring box. The percentage of voids was determined by weighing the amount of water added to fill the box:
| Size. | Method of Loading. | Per cent. of Voids. |
| 3 in. | 20-ft. drop | 41.8 |
| 3 in. | 15-ft drop | 46.8 |
| 3 in. | 15-ft. drop | 47.2 |
| 3 in. | Shovels | 48.7 |
| 1½ in. | 20-ft. drop | 42.5 |
| 1½ in. | 15-ft. drop | 46.8 |
| 1½ in. | 15-ft. drop | 46.8 |
| 1½ in. | Shovels | 50.5 |
| ¾ in. | 20-ft. drop | 39.4 |
| ¾ in. | 15-ft. drop | 42.7 |
| ¾ in. | 15-ft. drop | 41.5 |
| ¾ in. | 15-ft. drop | 41.8 |
| ¾ in. | Shovels | 45.2 |
| ¾ in. | Shovels | 44.6 |
| ⅜ in. | Shovels | 41.0 |
| ⅜ in. | Shovels | 40.6 |
| ⅜ in. | Shovels | 41.0 |
The table shows clearly the effect on voids of compacting the stone by dropping it; it also shows for the ¾-in. and the ⅜-in. stone loaded by shovels how uniformly the percentages of voids run for stone of one size only. Dropping the stone 20 ft. reduced the voids some 12 to 15 per cent. as compared with shoveling.
Table IV.—Showing Determined Percentages of Voids in Broken Stone from Various Common Rocks.
| Authority. | Percent Voids. | Remarks. |
| Sabin | 49.0 | Limestone, crusher run after screening out ⅛-in. and under. |
| " | 44.0 | Limsetone (1 part screenings mixed with 6 parts broken stone). |
| Wm. M. Black | 46.5 | Screened and washed, 2-ins. and under. |
| J. J. R. Croes | 47.5 | Gneiss, after screening out ¼-in. and under. |
| S. B. Newberry | 47.0 | Chiefly about egg size. |
| H. P. Broadman | 39 to 42 | Chicago limestone, crusher run. |
| " | 48 to 52 | " " screened into sizes. |
| Wm. M. Hall | 48.0 | Green River limestone, 2½-ins. and smaller dust screened out. |
| " | 50.0 | Hudson River trap, 2½-ins. and smaller, dust screened out. |
| Wm. B. Fuller | 47.6 | New Jersey trap, crusher run, 1/6 to 2.1 in. |
| Geo. A. Kimball | 49.5 | Roxbury conglomerate, ½ to 2½ ins. |
| Myron S. Falk | 48.0 | Limestone, ½ to 3 ins. |
| W. H. Henby | 43.0 | " 2-in size. |
| " | 46.0 | " 1½-in size |
| Feret | 53.4 | Stone, 1.6 to 2.4 ins. |
| " | 51.7 | " 0.8 to 1.6 in. |
| " | 52.1 | " 0.4 to 0.8 in. |
| A. W. Dow | 45.3 | Bluestone, 89% being 1½ to 2½ ins. |
| " | 45.3 | " 90% being 1/6 to 1½ in. |
| Taylor and Thompson | 54.5 | Trap, hard, 1 to 2½ ins. |
| " | 54.5 | " " ½ to 1 in. |
| " | 45.0 | " " 0 to 2½ in. |
| " | 51.2 | " soft, ¾ to 2 ins. |
| G. W. Chandler | 40.0 | Canton, Ill. |
| Emile Low | 39.0 | Buffalo limestone, crusher run, dust in. |
| C. M. Saville | 46.0 | Crushed cobblestone, screened into sizes. |
Table V.—Showing Percentages of Voids in Gravel and Broken Stone of Different Granulometric Compositions.
| | | | ———Per cent Voids in——— |
| Passing a ring of | 2.4" | 1.6" | 0.8" | Round | Broken |
| Held by a ring | 1.6" | 0.8" | 0.4" | Pebbles. | Stone. |
| Parts | 1 | 0 | 0 | 40.0 | 53.4 |
| " | 0 | 1 | 0 | 38.8 | 51.7 |
| " | 0 | 0 | 1 | 41.7 | 52.1 |
| " | 1 | 1 | 0 | 35.8 | 50.5 |
| " | 1 | 0 | 1 | 35.6 | 47.1 |
| " | 0 | 1 | 1 | 37.9 | 40.5 |
| " | 1 | 1 | 1 | 35.5 | 47.8 |
| " | 4 | 1 | 1 | 34.5 | 49.2 |
| " | 1 | 4 | 1 | 36.6 | 49.4 |
| " | 1 | 1 | 4 | 38.1 | 48.6 |
| " | 8 | 0 | 2 | 34.1 | .... |