structed, and keeping a daily account of the work done by

each gang.

Two pipe-layers may be connected with each gang if the trench can be rapidly excavated; otherwise two or more gangs may have a pair of pipe-layers in common, who lay pipe first in one trench and then in another, as sufficient length of each is excavated. For manholes, flush-tanks, and other masonry appurtenances a mason and two helpers may work together, passing from point to point as needed. For brick sewers two, four, or even six or eight masons may work together, the number in a gang usually being even. The number of masons' helpers depends somewhat upon the depth of the sewer, one or more extra ones being required to lower brick and mortar if the depth is considerable. For a depth of 8 feet or less approximately the following will be needed: two masons, four helpers; four masons, seven helpers; eight masons, fourteen helpers.

Besides the teams employed in hauling material to the work there should be one for carrying from place to place mortar-boxes, tool-boxes, and other heavy articles.

It is difficult to say anything definite concerning the number of men which should form an excavating-gang. There should be sufficient to keep the pipe-layers or masons constantly at work. Each gang or set of gangs to which a pair of pipe-layers or force of masons is assigned should be just large enough to open and back-fill trench at the average rate at which the sewer is laid. If the sewer frequently varies in depth or ease of digging it is often well to assign a force of masons or pipe-layers to two gangs, always endeavoring to so arrange that one of these is in soil rapidly trenched whenever the other is in deep or difficult work. For 8-foot excavation in good soil requiring little bracing 25 to 30 men at the shovel is usually an economical number; at 15 feet, if no excavatingmachinery is used, 60 to 80 will be required for equally rapid

work. On account of the considerable sheathing necessary at such depths and for other reasons it may be better, however, to still maintain the gang at 25 or 30 men, and assign the sewer-masons or -layers to two gangs. It is usually undesirable to change the size or personnel of gangs after they have once been gotten into good working shape.

If a trench runs into very wet soil or quick or running sand gangs as large as the above cannot be used to advantage, since not only must sheathing be set and driven right up to the excavation as it proceeds, but the pipe or sub-drain must be laid or foundation put in foot by foot as the bottom of the trench is reached; also an upheaval of the quicksand bottom, caving, and other accidents may cause occasional stoppages of the work for a few minutes, when almost the entire gang must lie idle or go to back-filling. In such difficult work on pipe sewers a gang may consist of a foreman, a sheather, two pipe-layers, and five or six laborers. If the ground is very wet it is advisable to open only a little trench at a time, since the more that is open below water level the greater the amount of water which will flow through the trench and interfere with the work. Under such circumstances the gangs

should be small.

If the back-filling is not to be rammed it is the custom of many contractors to use the entire gang for the last 20 to 30 minutes each day in back-filling. This arrangement has the advantage of not requiring an extra gang and foreman for back-filling. But if there are three or more gangs excavating it would perhaps be better to keep one gang continually backfilling. This is certainly advisable in all cases where the trench is to be thoroughly tamped.

The contractor, general foreman, or timekeeper should visit each gang just after the beginning and just before the ending of each day's work, at the least, to learn of any material needed or difficulty encountered, and also to get the

"time" of the men, which may have been taken by the foreman, or may better be taken directly by one of the three above mentioned.

If Italians or other non-resident workmen be employed (and if the work is in a small city and requires many men outside labor must be obtained) they are usually housed together in barns or empty houses or shanties constructed for the purpose on the outskirts of the city. If these can be located near a stream the men will usually take advantage of the opportunity to wash themselves and their clothes and keep in better health than if otherwise situated. The necessity for walking a long distance to and from work will result in decreased energy in their labor, and should be avoided. It will sometimes pay to have the teams carry them to and from the work. It will also be to the contractor's advantage to see that their food is wholesome. A considerable experience with Italian laborers has convinced the author that as a class they are more appreciative than are native laborers of both kindness and harsh treatment, and are shrewd readers of motives of conduct. If justly though firmly treated they are polite, obedient, and good workers, slow to wrath, but dangerous if ill treated. 'Sore-heads" among them should be gotten rid of at once.

Pay-days should come at as long intervals as possible, because of the diminished force which can be made to work for the following day or two, if for no other reason. For some reason masons seem to be peculiarly subject to the failing of

66

pay-day drunks," and if possible an arrangement should be made with them to pay their expenses wherever they wish to board and a small weekly amount of pocket-money, the balance being paid them when their work is completed. Monthly payments are generally made to the laborers, immediately after the payment of the monthly estimates.

ART. 70. TRENCHING BY HAND.

The line of the trench being given by centre stakes, the sides of the excavation are indicated by measuring the proper distance on each side of the stakes and stretching sash-cord or clothes-line there and marking the ground along this line by means of a pick. The laborers are then placed at regular intervals along the trench, varying from 6 to 20 feet, in single line in most cases, but if the trench is 8 feet or more wide they may be in double line. It may be well to define in some way, as by a mark in the ground or stake at one side of the trench, equal lengths of trench, one man being required to work within the limits of each length. Where possible it is desirable that this length be that which can be completed in a half or a whole day.

If the street is macadamized or gravelled or has a hard dirt surface a contractor's "rooter plow" may be used to break the surface; but this is not advisable in narrow trenches, nor should the surface be broken beyond the sides of the trench, since if sound it helps to prevent caving of the sides.

If there is any paving material on the street it should be thrown upon one side of the trench, and the remaining excavated material upon the other side, the material on each side being kept back a foot or two from the edge of the trench to allow a pathway for foremen and inspector and for lowering material, but still more to prevent excavated material from falling back into the trench. Thus one side of the street is left open to travel, the pile of paving material acting as a guard to the trench on that side. If so much soil is to be thrown out or the street is so narrow that it cannot all be placed upon one side of the trench it may be placed upon both sides, the paving material being kept separate, say along the outside edge of one bank; but it would be better to use excavatingmachinery and thus avoid blocking the street entirely. The

amount which can be placed upon one side of the street without covering the sidewalk may be increased by setting there a platform and guard, as shown in Fig. 11.

The first earth cast out should be thrown to what will be the outside edge of the bank, since it cannot be thrown there when the trench is deeper without double handling. The gutters should be kept open and free from any excavated material. Down to a depth of 9 to 12 feet the earth can be cast to the surface, although after 5 or 6 feet is reached it will

HA

FIG. 11.-EXCAVATION-PLATFORM.

surface to throw When the depth

be necessary to keep additional men on the back onto the pile the material so cast out. exceeds 9 to 12 feet it will be necessary to handle the material twice before it reaches the surface, by placing a platform or staging about 6 or 7 feet below the surface, onto which the earth is thrown by two to four men, and from which it is If the depth exceeds 16 thrown to the surface by one man. or 18 feet still another platform will be necessary about 7 or 8 feet below the first. These platforms are usually made by resting plank upon the braces or rangers of the sheathing. (Except in rock cuts there are almost no conditions under which a trench 10 feet or more in depth should be left unbraced.) The platform may consist of short pieces of plank placed crosswise of the trench, their ends resting on the rangers, or of long plank lengthwise of the trench resting upon the braces. The latter cannot well be used if the trench is