The miles of annual transportation of mail by railroad in 1852 amounted to 11,082,768, which increased to 113,995,318 in 1882, with an increase in the number of Railway Mail Service employees from 43 in 1846 to 3,072 in 1882. This wonderful expansion was but proportional with the development of the country at large. At the close of the war of the Rebellion, business was at its height. Industry and intelligence were seeking together new channels for their diffusion. The Pacific Railway was the grand conception that met this demand, and by its means were united the borders of the continent, and communication thus made more frequent and rapid between our interior, the West, and Europe: the most ancient civilization of the world in the Orient greeted the youngest in the Occident, and completed the girdle about the earth.

The lumbering stage and caravan laboring across the plains, and the swift mustang flying from post to post, frequently intercepted by the wily savage, were but things of yesterday, though fast becoming legendary. When those slower methods by which correspondence was conveyed at a great expense and delay, and current literature was to a great extent debarred, were supplanted by a continuous line of stages, it was considered a revolution in the wheel of progress, and the consummation. The possible accomplishments of the present day, if entertained at all at that time, were in general considered Munchausen, and not difficulties to be surmounted by practical engineering and undaunted perseverance. The civilization of the world has kept pace with its channels of communication and has accordingly rendered invaluable aid to it. In our country the field in this direction is exceedingly broad.

There is no branch of the government service that reaches so near and supplies the wants of the people as the Post-Office Department, and whose ramification may not be inaptly compared to the human system with its arteries filled with the life-current coursing through the veins and diffusing health and vigor to the various parts; in the same manner the people in the different sections of the country interchange their information. The centres of art and literature, conveying to the vast producing region in the West the products of their refined taste, scientific research, and mechanical achievements, keep alive and propagate the spirit of inquiry, making remote parts of the nation homogeneous in tastes, knowledge, and a common interest in all matters of national advancement.

If a map of the United States with every railway that crosses and recrosses its broad surface were laid before us, it would appear that a regulated system for an expeditious transmission of the mails in such an intricate confusion of lines, apparently going nowhere yet everywhere, would be an impossibility; but by study and untiring energy this has been accomplished.

The machinery of the Post-Office Department is a system of cog-fitting wheels, in all its component parts; and were it not so, in the necessarily limited period and space allotted, the work in postal-cars could not be successfully accomplished.

The interior dimensions of postal-cars vary, from whole cars sixty feet in length, to apartments five feet five inches in length by two feet six inches in width. The most comprehensive conception of the practical working of the postal-car system, can be formed in a railway post-office from forty to sixty feet in length; with this in view, we will make a trip in one. A permit to ride in the car, signed by the superintendent of the division of the service, is necessary to allow us the privilege; and it is also required of clerks belonging to other lines. This rule is necessary, in order that the clerks may perform their work uninterruptedly and correctly; and also to exclude unauthorized persons from mail apartments. After a hasty exchange of salutations with the four clerks, the "clerk in charge" notes our names on his "trip report," and we are assigned a spot in the contracted space, where, we are assured, we will be undisturbed, at least for a while. The trip report mentioned is used in noting connections missed, and other irregularities that may occur. The interior of the car is fitted up with a carefully-studied economy of space, upon plans made under the supervision of the superintendent of the division, or chief clerk of the line. Occupying one end of the car are cases of pigeon-holes, or boxes, numbering from six hundred to one thousand, arranged in the shape of a horse-shoe, for the distribution of letters. These boxes are labeled with the names of the post-offices on the line of road, connecting lines, States, and prominent cities and towns throughout the country. A long, narrow aisle passes through the centre of the car, on both sides of which are racks for open sacks and pouches, into which packages of letters and pieces of other mail matter are thrown; on the sides above are rows of suspended pouches, with their hungry mouths open. By this plan, in this contracted space, upwards of two hundred different pouches and sacks can be distributed into between the termini. On one side of the aisle is a narrow counter, upon which the mail matter is emptied from the pouches and sacks; this is hinged to the pouch-rack, and can be swung back, to enable the clerks to get at the pouches more easily. The space beyond, divided by stanchions, is for the stowage of mails, and for their separation into piles.

In order that a minute may not be lost, when passing through tunnels or standing in dark railway-stations, the lamps are kept burning from the start to the finish. The last wagon, gorgeously suggestive of a circus, has arrived with its load of mail, and the busy work receives at once a new impetus. Several loads, however, have already arrived, and have been disposed of as much as possible; for the work begins, in some cases, several hours before the starting of the train. Transfer clerks and porters deliver the pouches and sacks into the car, the label of each being scanned and checked by the clerks, to detect if all connections due are received, and that no mail may be delayed by being carried out on the road with the other mail and returned. The last pouch is scarcely received, when a sudden, but not violent, shock announces that the locomotive is attached to the train, and the start about to be made. The sound of the gong, seconded by the electrifying and resonant "Aboard!" of the conductor, and the post-office on wheels is under way. Now, all is a scene of bustle, but not confusion. The two clerks, to whom are assigned the duty of distributing direct packages of letters and newspaper mail, including merchandise, deftly empty the pouches, out of which pour packages of letters and circulars, to be distributed unbroken into pouches, and others labeled to this route and different States, which are in turn to be separated into packages by routes, States, and large towns, at the letter-case. To the clerk in charge is assigned the sorting of such letters as are destined to distant routes or terminal connecting lines; and his associate, or second clerk, is busy distributing letter mail for local delivery, and into separations for intermediate connections.

In addition to sorting letters, the clerk in charge has charge of the registered mail, which requires special care in its reception and delivery, booking and receipting therefor. Large pouches of registered mail are also placed in his charge, en transit between large cities, and represent great value. The peculiar tooting of the whistle, or a peculiar movement of the train around a curve, warns the fourth clerk, who is on the alert, of a "catch" station; the letter mail for that post-office is quickly deposited by the local clerk in the pouch, the lock is snapped, and he is standing at the door not a minute too soon or too late; the pouch is thrown out at a designated spot and one deftly caught an instant after without a slackening of the speed of the train. The pouch thus caught is taken to the counter, opened and emptied by the fourth clerk, and the letters immediately placed in the hands of the second clerk, who assorts the local mail; the through letters, or those destined to go over distant lines beyond the terminus, are sorted by the clerk in charge; the local, or second, clerk distributes his mail as rapidly as possible, with a watchful eye for letters, etc., to be put into the pouch to be delivered at the next station; the pouch is locked and everything is ready for the next delivery and "catch." When the stations at which pouches are caught are within a mile or two of each other, the greatest activity is needed to assort the mail between stations, to avoid carrying mail by destination and subjecting it to considerable delay before its delivery by a railway post-office on the train to be met at a point perhaps many miles ahead.