The mixer was a No. 5 Chicago Improved Cube Mixer, operated by a gasoline engine; a larger size would have been preferable since a batch required only two-thirds of a bag of cement which had to be measured which required the services of an additional man. The mixer was in operation 194 hours and mixed 7,702 batches (1,217 cu. yds.), or a batch every 87 seconds, or 6.3 cu. yds. per hour. During the last ten days it mixed a batch every 78 seconds while running. The best short record made was 291 batches in five hours, or one batch every 63 seconds, this being at the rate of 58 batches equal to 9.2 cu. yds. of concrete in place per hour, or nearly 1/6 cu. yd. per batch. It took about ½ minute to mix the concrete and about the same length of time to charge and discharge the mixer.
To convey the concrete from the mixer to the culvert walls a 1 cu. yd. drop bottom car was used. This car ran on 30-in. gage tracks carried on a trestle straddling the culvert walls and having its floor high enough to clear the arch. A track ran lengthwise of the trestle over each culvert wall, and a cross track intersecting both with turntables ran to the mixer. Three men handled the car, a round trip to the extreme end of the trestle being made in about 3 minutes. In the meantime the mixer was discharging into a small hopper which unloaded into the car on its return. One only of the three sections, of the culvert was built at a time, both walls being brought up together. After a point had been reached about 2 ft. above the springing on both walls, one track was removed and the other was shifted to the center of the trestle.
Forms.—There was used in the forms 15,000 ft. B. M. of 2-in. dressed lagging for face work, 21,000 ft. B. M. rough lumber for back work, and old car sills for studding. No charge was made for studding except the cost of loading, the cost of the remaining lumber was $16 per M. for dressed and $12.50 per M. for rough. A credit of one-third the cost was allowed for the old material recovered. The total cost of the labor of erecting the material in forms, bins and platforms was $666. The work was done by a bridge crew of white men, the average rate of wages per man, including the bridge foreman's time, being $2.20 per day. In addition a mason at $3.50 per day and a carpenter at $2.25 per day worked with the bridge crew in erecting forms.
Cost.—The cost of the 1,217 cu. yds. of concrete in the culvert was as follows:
| Item. | Per cu. yd. |
| 1.08 bbls. cement at $1.72 | $1.85 |
| 0.47 cu. yd. sand at 30 cts. | 0.14 |
| 0.25 cu. yd. broken stone at 51 cts. | 0.13 |
| 0.8 cu. yd. slag at 26 cts. | 0.21 |
| Lumber in forms, etc. | 0.30 |
| Miscellaneous materials | 0.05 |
| Labor, unloading materials | 0.11 |
| Labor, mixing and placing concrete | 0.42 |
| Labor, building forms | 0.55 |
| Labor, not classified | 0.18 |
| Labor, excavating 40 cts. per cu. yd. | 0.28 |
| Labor, back filling and tearing down forms | 0.10 |
| —— | |
| Total | $4.32 |
CULVERTS FOR NEW CONSTRUCTION, WABASH RY.—The following data relate to culvert work carried out in constructing the Pittsburg extension of the Wabash Ry. in 1903. All the work was done by contract.
Plant I: This plant was located on a hillside with the crushing bins above the loading floor or platform which extended over the top of the mixer, so that the crushed stone could be drawn directly from the chutes of the bins and wheeled to the mixer. The sand was hauled up an incline in one-horse carts and dumped on this floor, and was also wheeled in barrows to the mixer. The proportions used were 4 bags of cement, 4 barrows of sand and stone dust and 7 barrows of crushed stone. A ⅞-cu. yd. mixer was used and it averaged 40 cu. yds. per 10-hour day at the following cost for labor:
| Item. | Per day. | Per cu. yd. |
| 1 foreman | $ 3.00 | $0.08 |
| 3 men charging with barrows | 4.50 | 0.11 |
| 1 man attending engine and mixer | 2.50 | 0.06 |
| 2 men loading concrete barrows | 3.00 | 0.08 |
| 4 men wheeling concrete barrows (100 ft.) | 6.00 | 0.15 |
| 4 men ramming concrete | 6.00 | 0.15 |
| 4 men wheeling and bedding rubble stones | 6.00 | 0.15 |
| ——— | —— | |
| Totals | $31.00 | $0.78 |
Assuming ⅓ ton of coal per day at $3 per ton, we have 2 cts. more per cubic yard for fuel.