[75]. See article by E. W. Bush in Eng. News-Record, Vol. 85, 1920, p. 122.
[76]. An unbalanced proposal is one in which the bids on some of the items are obviously low and on other items are obviously or suspiciously high. The purpose of submitting unbalanced bids is to keep secret the true or supposed cost of the work to the contractor or to obtain more money by bidding high on those items which are believed to have been underestimated by the Engineer. A low bid is made on other items in order to keep down the total amount of the bid.
[77]. Taken mainly from specifications of the Sanitary District of Chicago and the Baltimore Sewerage Commission, with miscellaneous selections from other sources.
[78]. Restrictions are placed on work done outside of ordinary working hours in order that the Contractor may not perform work in the absence of an engineer or inspector.
[79]. Cost Keeping and Management, by Gillette and Dana. Practical Cost Keeping for Contractors, by F. R. Walker. Cost Keeping in Sewer Work, by K. O. Guthrie in Eng. Contracting, Vol. 28, p. 238, 1905. Sewer Construction Records at Scarsdale, Eng. News-Record, Vol. 83, p. 111, 1919.
[80]. See Planning and Progress on a Big Construction Job, by Chas. Penrose, Eng. News-Record, Vol. 84, 1920, pp. 554 and 627.
[81]. See also “Ownership and Operation of Trench Excavators by the Water Department of Baltimore,” by V. B. Seims, presented before Am. Water Works Association, June 9, 1921.
[82]. Eng. and Contracting, Vol. 48, 1917, p. 492.
[83]. Earth Excavation by A. B. McDaniel.
[84]. Courtesy, Sanitary District of Chicago.