letters each, and can be despatched as frequently as one every eight or ten seconds. It will be seen, therefore, that by means of the pneumatic tubes a practically continuous flow of the mails can be maintained between stations. The pneumatic tubes are not owned by the Government, but the service is leased on a yearly rental basis. Under the terms of the lease the company that owns the tube system operates it, and the Government delivers to the despatching points within the different stations and terminals the mail to be transported. Upon arrival at its destination the mail is again delivered to the postal employees, who are ready to receive it. There are approximately twenty-eight miles of double tubes, so that mail can be despatched in both directions at the same time. During the period the system was in operation before the tubes conveyed the mails with remarkable efficiency, and it is said that as to stoppages and breakdowns, etc., their operation was 99.79 per cent. perfect. In one day 27,243 containers were despatched through the tubes, with a total capacity of more than 10,000,000 letters. They averaged for a year, though not used to maximum capacity, 5,000,000 letters a day. One advantage of the pneumatic tubes is their freedom from interruption by inclement weather. As the tubes are below the surface of the street, conditions of ice, snow, and sleet, which are embarrassing to motor vehicles, do not interrupt operation. At different times in several of our cities vehicles conveying the mails have been "held up," but with the tubes, robbery is practically impossible. It is anticipated that with the tube system resumed a large percentage of the letter mail intended both for city delivery and for despatch to other points will be materially advanced in delivery.