There seems to be no good reason for allowing lost interest during construction as an item in the physical valuation of a property, any more than for allowing all of the lost interest, up to the time when the property begins to yield a return equal to the rate of interest. It is one of the problems in finance, and is much better treated as an element in the going value, as shown in the above illustration. One of the most difficult factors on which to agree in computations of this nature is the element of time required for the hypothetical starting plant to acquire the business. Were it not for this uncertainty, going value could be computed with mathematical precision by the method suggested. In determining the physical valuation on the basis of cost of reproduction, such items as cost of taking up and replacing street paving over the pipe lines, cost incurred by reason of sewers and drains encountered, interference due to electric wires and conduits, interference of traffic, and other metropolitan conditions which add greatly to the cost of construction, must be allowed. Wherever such metropolitan conditions exist, there must also be present a corresponding necessity for the use of water under pressure. People use water because of necessity or convenience, and not on account of any feeling of obligation or loyalty to the water company. TABLE 14.—COMPUTATION OF GOING CONCERN VALUE, BASED ON REASONABLE RATES. ╒════════════════╤═════════════════╤════════════════╤═════════════════╕ │ Year, dating │ Legitimate │Hydrant, rental │Domestic revenue │ │ from beginning │ profits of the │ taken over by │ of starting │ │of construction.│ going plant. │starting plant. │ plant. │ ├────────────┬───┼─────────────────┼────────────────┼─────────────────┤ │Construction│1st│$60,000 + 0.06_x_│ 0│ │ │ period. │ │ │ │ │ │ │ 2d│ 60,000 + 0.06_x_│ 0│ │ │ │ 3d│ 60,000 + 0.06_x_│ $20,000│ $20,000│ ├────────────┼───┼─────────────────┼────────────────┼─────────────────┤ │ Business │4th│ 60,000 + 0.06_x_│ 40,000│ 55,000│ │development │5th│ 60,000 + 0.06_x_│ 40,000│ 80,000│ │ period. │6th│ 60,000 + 0.06_x_│ 40,000│ 90,000 + 0.06_x_│ └────────────┴───┴─────────────────┴────────────────┴─────────────────┘