Aside from the durability of the timber employed, plenty of face for the rail bearings, and uniform thickness and length, are very important requirements in contracts for ties. While white oak is generally considered the most durable for this purpose, the growth of this timber is limited except in certain sections of the country, so that cedar, cypress, chestnut, and yellow pine are more commonly used than any other class. The millions of them used for renewals and new roads each year are gradually reducing our forests; and, like some of the European roads, we shall some day fall back upon metal, which (while its life may not be measured) will make so rigid a track that the traveller over long distances will be worn out with his journey, and the rolling stock will require frequent repairs and overhauling. The practice of creosoting cross-ties is growing rapidly, and this tends to increase their durability three or four times. While the first cost of such ties may be double that for the unprepared timbers, the result in the end is economical, for the labor alone required to take out an old tie and put in a new one costs at least twelve cents. The general store-room is properly the intermediate stage, so far as supplies are concerned, between the different departments of the road and the Auditor, who charges up all material used to the different accounts into which his system is divided. Properly, everything in the nature of material, however small, directly or indirectly passes through the Store-keeper's books. An account is kept with each locomotive, station agent, switchman, and flagman, so that to a penny everything consumed in the operation of a road is accurately known. To accomplish this the Store-keeper, of course, must be a good accountant, and at the same time be more or less of an expert in railroad material. Under an economical administration of his affairs he is able to save a great deal of money for his company. By his system, with the aid of data from the mechanical department, he can tell the average number of miles run during the year to a pint of oil or a ton of coal; the number of pounds of coal consumed per mile run, as well as the number of pints of oil for the same distance. He can give in detail the cost in cents per mile run for all the oil, tallow, and waste, fuel, and other supplies consumed, and can account to a nicety for all the lanterns, brooms, hardware, and other material which he has received and distributed. The following statement of averages represents fairly what it costs to run a locomotive under ordinary conditions: _Averages._ Number of miles run to pint of oil 15.32 Number of miles run to ton of coal 46.17 Number of pounds of coal per mile run 48.62 Number of pints of oil per mile run 0.06 _Cost in Cents per Mile Run._