The use of travelling post offices, with mail clerks assorting and distributing the mails from the railways in the course of their trips, was an early feature of the postal service in Canada. This mode of utilizing the railways had been in operation in England since 1838, and before the leading railways in Canada were completed, an officer of the post office department was sent to England to study the system. Thus, by 1857, this system, which is the leading feature of mail conveyance and distribution, was in full course in this country seven years earlier than in the United States. But gratifying as were the results from the use of railways in the conveyance of mails, through the sparsely-settled districts over the immense stretches of our territory, the substitution of steam for horse conveyance introduced a perplexing financial problem. The postmaster general noted the peculiar fact that while passengers and merchandise reaped the benefit of improved speed with an accompanying reduction in the expense, the change threatened to burden the public with a vastly augmented charge for the mail service. Comparing the service by railway with that by stage, it was noted that, while the stage driver waited at each office he visited, until the mail he brought was assorted, and arranged for his farther conveyance, it was impossible owing to the brevity of the stops at the stations, to do this in the case of the mails carried by railway. The post office consequently was compelled to train and employ a distinct class of clerks to travel on the trains, and perform that duty while the train was in movement. A portion of a car--generally about one-third--was partitioned off and fitted up exclusively for postal service. The salaries of these clerks constituted what the postmaster general regarded as the enormous expenditure of $32,000 a year; and the necessity created by the nature of the railway service for the provision of an office on the trains, formed the principal ground on which a comparatively high rate of compensation was claimed by the companies. But that was not all. The railways not being able, like the stage coach, to exchange the mails directly with the post offices of the towns along the line, side services of an expensive character were required to maintain the connection between the post offices and the stations. The expenditure for this class of service, coupled with that for the employment of the clerks who travel on the railway, exceeded, in most cases, the whole of the previous expenditure for the superseded service by stage; and then there were the demands of the railways to be satisfied.