Ballasting, track laying, and surfacing were divided into three and four classes, in order to cover the different general types of railroads, and prices per mile were fixed. On Upper Peninsula roads ballasting was estimated at a higher price than on Lower Peninsula roads, while ties and timber construction were estimated at a lower figure. In addition to these prices, secured by averaging several years' quotations, or by agreement of experienced construction engineers, many valuable figures were obtained from manufacturers of locomotives, cars, mechanical equipment, and bridges; and in several cases access was given to the mechanical cost data of the larger roads. Specifications for locomotives, cars, and shop tools were sent out to builders with a request that they give average prices for a period of years. From all this mass of data the unit prices for the valuation were determined. For locomotives, values were plotted for engines of different weights, in order to establish a curve, and curves representing deterioration, scrap value, and major repairs were also plotted, so as to ascertain diagrammatically the value of an engine of given weight and stated condition. The tables and diagrams proved of incalculable benefit in reducing the work, and in securing that absolute uniformity of method necessary to give the appraisal standing. It may not be amiss to state here that in such a work no set of unit prices could possibly be adopted which would not work some apparent injustice. A number of Michigan lumber roads were of the cheapest possible type of construction, and any unit price applied to ties or timber, which would be at all reasonable for such roads as the Michigan Central, Grand Rapids and Indiana, Pere Marquette, and others, would be far in excess of the actual money paid out by these little roads. A few individual instances of such apparent discrepancy were cause of complaint and criticism, but, on analysis, very generally, these did not appear to be anything but a disagreement with book values, in which ties cut off the right of way were treated as having no cost; or in some similar item certain local conditions may have made the first cost so low as to amount to a donation of property. Conceding the propriety of the objections, the reason for making the appraisal was to furnish information on which the legislature might determine whether the State should go from a specific to an ad valorem basis, and in view of this purpose the objections became unimportant, as they applied to but a few miles of road. _Classification._—All work of computation was classified in strict accordance with the Interstate Commerce Commission's classification of construction accounts, to which were added one or two classifications not recognized by that Commission, and final summaries were returned on sheets similar to those illustrated by Figs. 1 to 10.