The inspection in the field, in addition to the placing of a percentage for depreciation, should involve a complete check of the inventory, a correction of all errors, due to the construction of new property or the destruction or removal of old, and a compilation of all information required for a complete, correct, and intelligent appraisal of the physical property by the computing office. Every appraisal is different, and every property offers new problems and diverse conditions. These must be met, and therefore the field inspector must call particular attention to all matters specially affecting the values of the property he is inspecting. It is impossible to anticipate all these conditions in advance, although the use of carefully prepared blanks and the standardizing of the form in which the data are gathered greatly simplify the work, not only in the office, but in the field. III. The Computation. On the completion of the field work, with all the preliminary data in the office, the computation must proceed, and with this part of the work there are many questions which must be taken up, considered, and definitely answered. The classification and arrangement of the information as to the property to be valued, the costs and prices of the various materials entering into construction, the making and checking of such tables as may be required for estimating, the computing, checking, filing, indexing, and the various other routine details of work need not be referred to specially, as they must be worked out for each appraisal. The matters of principle that will be met are more important, and, while it would be impossible to mention all that may come up, it may not be amiss to refer to a few. (_a_) In making an appraisal of several properties, to what extent shall these properties be grouped or classified? (_b_) What unit prices shall be assigned in the estimates of cost of reproduction, and how shall they be determined? (_c_) How shall right-of-way and real estate values be ascertained? Shall such elements as appreciation, or any increments due to the purpose for which the land is used, be treated as physical or non-physical values? (_d_) What method shall be finally adopted in determining depreciation? What elements shall depreciation be made to cover? (_e_) What elements of cost or appreciation shall be treated as parts of the physical property although not capable of inventory, and what shall be treated as non-physical? (_f_) Is an allowance for contingencies a proper item to include in an appraisal? (_g_) What weight shall be given the matters of adaptability, proper or improper design, and the economics of location? (_h_) How shall the values of such property as locomotives, cars, etc., be geographically assigned? (_i_) What is the effect upon values of large terminals? (_j_) Should an allowance be made by reason of rapid development of the art?