Every examining engineer should know (or can obtain) the prices for materials, labor, etc., during these periods of original construction, extension, etc. If the prices are the same, or about the same, as at the time of purchase, the above total stands as the cash expended; if there should be much difference—and sometimes there is—take the detail of the materials as found in the vouchers, affix the proper prices, and do the same with labor, etc., and this total will be what, in the judgment of the examining engineer, the plant should have cost. A mean between this latter total and that in 8th is taken, in order to be fair and equitable. This amount, in place of that given by 8th, is then used as the cash expended on the physical property. If no difference is found in prices, then the total cash as shown by 8th is considered as the total to be hereafter used. 9th.—A careful detailed inventory is now made of the physical property as it exists at the date of examination. This often requires some excavation in order to determine sizes, quantities, and conditions. The prices used to ascertain the total of the inventory are made by taking the average of all those paid for materials, labor, etc., of the same class, during each year of the property's existence. (The writer considers it manifestly unfair to use the current prices in this calculation, for they may be very much below or above those actually paid, and in either event an injustice would be done, whereas, if the average prices are used, the examiner cannot be accused of unfairness.) To this total cost, as shown by the inventory, 5% is added for engineering and superintendence; 3% for general office salaries, 2% for general expenses, 1½% for legal and organization expenses, and from 5 to 10% for contingencies. (This latter percentage depends on the judgment of the examiner, who, after studying the local conditions carefully, can determine from his own experience what difficulties have been met in the construction. It is not believed that a hard-and-fast rule can, in equity, be laid down for this latter percentage.) This total represents the value of the tangible property, based on the inventory. The inventory cost and that set forth in 8th (or possibly as modified by prices current when the plant was built) are averaged, and this result, plus the supplies on hand, is the fair and equitable amount of cash which has been expended on the property. This is used in finding the "Fair and Equitable Value." 10th.—Next take the inventory of the plant set forth in 9th, affix the current prices at the date of appraisal, and to this total add the same percentages for engineering, etc., as set forth in 9th. This gives the cost of reproducing the property, with the same classes of materials, size and make of engines, etc., as is now in it, to which total add the cost of materials on hand for the total of cash required to be expended at current prices to reproduce the plant as it exists.