Trap,Boston, Mass.2.78
"Duluth, Minn.2.8 to 3.0
"Jersey City, N. J.3.03
"Staten Island, N. Y.2.86
Gneiss,Madison Ave., N. Y.2.92
Granite,New London, Conn.2.66
"Greenwich, Conn.2.84
"Vinalhaven, Me.2.66
"Quincy, Mass.2.66
"Barre, Vt.2.65
Limestone,Joliet, Ill.2.56
"Quincy, Ill.2.51 to 2.57
Limestone, (oolitic)Bedford, Ind.2.25 to 2.45
"Marquette, Mich.2.34
"Glens Falls, N.Y.2.70
"Lake Champlain, N. Y.2.75
Sandstone,Portland, Conn.2.64
"Haverstraw, N. Y.2.13
"Medina, N. Y.2.41
"Potsdam, N. Y.2.60
"(grit) Berea, O.2.12

Table VII.—Specific Gravity of Common Minerals and Rocks.

Apatite2.92-3.25
Basalt3.01
Calcite, CaCO32.5-2.73
Cassiterite, SnO26.4-7.1
Cerrusite, PbCO36.46-6.48
Chalcopyrite, CuFeS24.1-4.3
Coal, anthracite1.3-1.84
Coal, bituminous1.2-1.5
Diabase2.6-3.03
Diorite2.92
Dolomite, CaMg (CO3)²2.8-2.9
Felspar2.44-2.78
Felsite2.65
Galena, Pbs7.25-7.77
Garnet3.15-4.31
Gneiss2.62-2.92
Granite2.55-2.86
Gypsum2.3-3.28
Halite (salt) NaCl2.1-2.56
Hematite, Fe2O34.5-5.3
Hornblende3.05-3.47
Limonite, Fe3O4 (OH)63.6-4.0
Limestone2.35-2.87
Magnetite, Fe3O44.9-5.2
Marble2.08-2.85
Mica2.75-3.1
Mica Schist2.5-2.9
Olivine3.33-3.5
Porphyry2.5-2.6
Pyrite, FeS24.83-5.2
Quartz, SiO22.5-2.8
Quartzite2.6-2.7
Sandstone2.0-2.78
" Medina2.4
" Ohio2.2
" Slaty1.82
Shale2.4-2.8
Slate2.5-2.8
Sphalerite, ZnS3.9-4.2
Stibnite, Sb2S34.5-4.6
Syenite2.27-2.65
Talc2.56-2.8
Trap2.6-3.0

Table VIII.—Showing Weight of Stone with Different Percentages of Voids for Different Specific Gravities.

Weight in Lbs. per cu. yd. when Voids are
Specific Gravity.Weight in Lbs. per cu. ft.Weight in Lbs. per cu. yd.30%35%40%45%50%
1.062.3551,6841,1781,0941,010926842
2.0124.73,3672,3572,1872,0201,8521,684
2.1130.93,5362,4752,2982,1211,9451,768
2.2137.23,7042,5932,4082,2222,0371,852
2.3143.43,8722,7112,5172,3232,1301,936
2.4149.74,0412,8282,6262,4242,2222,020
2.5155.94,2092,9462,7362,5252,3152,105
2.6162.14,3773,0642,8452,6262,4082,189
2.7168.44,5463,1822,9552,7272,5002,273
2.8174.64,7143,3003,0642,8282,5932,357
2.9180.94,8823,4183,1742,9292,6852,441
3.0187.15,0513,5363,2833,0302,7782,526
3.1193.35,2193,6533,3923,1312,8712,609
3.2199.55,3883,7713,5023,2322,9632,694
3.3205.85,5563,8893,6113,3333,0562,778
3.4212.05,7244,0073,7213,4343,1482,862
3.5218.35,8934,1253,8303,5353,2412,947

In buying broken stone by the cubic yard it should be remembered that hauling in a wagon compacts the stone by shaking it down and reduces the volume. Table IX shows the results of tests made by the Illinois Highway Commission to determine the settlement of crushed stone in wagon loads for different lengths of haul. The road over which the tests were made was a macadam road, not particularly smooth, but might be considered as an average road surface. The wagon used was one with a dump bottom supported by chains, which were drawn as tight as possible, so as to reduce the sag to a minimum. It will be noticed that about 50 per cent. of the settlement occurs within the first 100 ft., and 75 per cent. of the settlement in the first 200 ft. Almost all of the settlement occurs during the first half mile, as the tests showed practically no additional settlement for distances beyond. Some of the wagons were loaded from the ground with shovels, others were loaded from bins, the stone having a 15-ft. drop, which compacted the stone a little more than where loaded with shovels, so that there was somewhat less settlement. But at the end of a half mile the density was practically the same, whatever the method of loading. The density at the beginning and at the end of the haul can be compared by the weight of a given volume of crushed stone. For convenience, the weight of a cubic yard of the material at the beginning of the haul and at the end was computed from the known contents of a wagon.

Table IX.—Showing Settlement of Broken Stone due to Different Lengths of Haul on Ordinarily Good Road in Wagons.

Per cent Settlement for Hauling. Weight per Cu. Yd. in Lbs.
Size. Method of Loading.100'200'300'400'500'600'700'½ Mile1 Mile At start. At finish.
Screenings15 ft. drop.... ....................... 11.5 11.5 2,518 2,840
Screenings15 ft. drop.... ....................... 12.6 12.62,518 2,886
Screenings15 ft. drop 7.3 8.3 8.9 9.2 9.510.110.1 11.2 ....2,450 2,770
Screenings15 ft. drop 5.0 9.610.210.210.410.410.4 12.4 ....,425 2,780
1½ inch15 ft. drop ........................... 11.5 11.5[C]2,305 2,600
1½ inch15 ft. drop 5.3 6.2 7.1 7.7 7.9 8.0 8.3 9.2 ....2,380 2,625
1½ inch15 ft. drop 2.6 3.7 4.9 5.3 5.3 5.3 5.4 5.4 ....2,450 2,600
1½ inchShovels 3.5 4.1 4.8 5.3 5.3 5.7 6.5 7.25 ....2,270 2,445
1½ inchShovels ........................... 12.6 12.62,305 2,642
3 inch15 ft. drop ........................... 10.1 10.12,376 2,638
3 inch15 ft. drop 3.5 4.2 4.5 4.8 5.0 5.0 5.0 6.0 ....2,360 2,505
3 inch15 ft. drop 0.5 2.5 2.5 4.1 4.3 4.3 4.3 4.9 ....2,470 2,595
3 inchShovels ........................... 12.6 12.62,270 2,601
3 inchShovels 5.0 5.6 6.5 6.5 6.8 6.8 6.8 7.1 ....2,335 2,510

[C] —Same per cent of settlement for two-mile haul.