A summary of the information available is herewith presented: Great Britain.-In Great Britain the tubes are about 3 inches in diameter and are used only as an adjunct to the telegraph system. It is understood that they are installed in several cities in England and also in Dublin, Ireland. Statistics of 1899 showed that in London alone there were about 38 miles.

France. The tubes are of two types, 2.36 inches and 3.15 inches in diameter, and they are installed in the cities of Paris, Lyon, and Marseille. They are mainly an adjunct to the telegraph system, but are also used for the transmission of special-delivery letters and cards. In 1899 there were reported to be about 167 miles in use. In 1908 the mileage is reported as 217 miles, of which Paris has over 210 miles, Lyon, 2.73 miles, and Marseille, 3.89 miles.

Germany. The tubes in use in Germany are about 2 inches in diameter, and are reported to be in use in Berlin, Hamburg, and Frankfort on Main. They were originally installed as an adjunct to the telegraph system, but in the city of Berlin, are also used for the transmission of special-delivery letters and cards. In 1899 it was reported that there were 73 miles in Berlin and 54 miles in Hamburg. Recently it has been reported that the German postal administration has under consideration a proposed tunnel system for Berlin, to run between the principal post-office stations and the Potsdam depot. The proposed tunnel is planned to be 29 inches high by 71 inches wide. The design is to use a small car with capacity of carrying a single bag of mail and run at a speed of about 25 miles per hour. Several cars with an electric engine will form a train to be propelled on a railway track of 16.13 inch gauge within the tunnel. It is said that in Berlin the pneumatic-tube service for special-delivery letters has practically abolished urban telegrams. Telegrams cost the public about 1 cent a word, and unless sent "urgent" with treble toll are very little faster than a tube letter.

Italy. There is not at present any pneumatic-tube service in Italy, but in September, 1908, official announcement was made that the Government was about to install pneumatic-tube service (3.6-inch diameter) in Naples, Milan, and Rome between the central post-offices and the railway stations in each city. The intention was to use the tubes for the transmission of telegrams and also special-delivery letters. The ordinary letter mail would, however, continue to be carried by horse-drawn wagons or automobiles.

Austria. It is known that there is pneumatic-tube service in Vienua which is used in the transmission of telegrams and special-delivery letters, but statistics are not at hand as to its extent.

IMPORTANCE OF CITIES IN WHICH PNEUMATIC-TUBE SERVICE IS NOW

PROVIDED.

The appropriation for pneumatic-tube service for the current fiscal year is less than one-half of 1 per cent of the total postal appropriation. Its expenditure is for service in six of the most important revenue-producing post-offices in the United States. These postoffices (Boston, New York, Brooklyn, Philadelphia, Chicago, and St. Louis) collected during the past fiscal year $50,723,364, this being 26 per cent of the total postage receipts of the country. The first

class mail (the most profitable class) originating at these six postoffices is about 27.7 per cent of all first-class mail originating in the United States. The number of pieces reported as received from the public daily is 8,344,093, although it is thought this total is 30 per cent higher than the average daily receipts throughout the year.

The special-delivery mail is also a profitable class of mail, and its volume would be greatly increased in certain cities by adequate tube service. At the six post-offices mentioned there were delivered last year 4,015,468 special-delivery letters, these representing nearly_30 per cent of all special-delivery matter in the entire country. The number of special-delivery letters delivered in the six cities in 1897 was 1,481,352, thus showing a growth of 177 per cent in eleven years. It is assumed that with a complete tube system in New York City south of One hundred and twenty-fifth street an immense increase in special-delivery letters could be confidently looked for in a short time.

The first-class mail of city origin for city delivery is reported by the post-offices in the six cities as 2,629,561 pieces daily, this being about 31 per cent of their total first-class mail. This class of matter is not subject to general postal charges for handling and transportation, and is estimated to produce a profit of about $9,000,000 per annum. This class of mail would be especially benefited and increased by a complete system of pneumatic-tube service in certain cities.

The important postal statistics of the pneumatic-tube cities are shown in the following table:

Postal statistics a of cities in which pneumatic-tube service is provided.

a Statistics, except as otherwise stated, are of October, 1908.

b Population in some cases is based on letter carriers' census and duplicates persons in business and resi

dential districts.

Postal statistics of cities in which pneumatic-tube service is provided-Cont'd.

PROPORTION OF FIRST-CLASS MAIL TRANSPORTED BY TUBE.

From the preceding table it will be seen that the percentage of firstclass mail sent by tube is as follows:

In other words, there is a total daily of 13,632,534 pieces of firstclass mail transmitted by tube out of a total of 30,176,049 pieces, or 45.1 per cent.

FIRST-CLASS MAIL ACTUALLY ADVANCED BY TUBE.

Out of a total of 15,989,047 pieces dispatched daily at the tube offices, 1,835,338 pieces (or 11.4 per cent) are reported to have been actually advanced in dispatch. Out of a total of 14,187,002 received daily, 787,533 pieces (or 10.6 per cent) are reported to have been actually advanced in delivery. The total number of pieces actually advanced daily by tube was therefore 2,622,871. The total annual pay for tube service early in October, when these statistics were taken, was $615,400 or, say, $1,686 per day.

The average cost per piece actually advanced was therefore less than one-tenth of 1 cent (six-tenths of 1 mill).

ADVANTAGES AND LIMITATIONS OF PNEUMATIC-TUBE SERVICE.

SPEED.

Probably the most attractive advantage in pneumatic-tube service is the possible speed of transmission. The contracts call for a sustained speed of 30 miles an hour between stations. This high rate

of speed is in strong contrast with the contract rate for mail-wagon service, which would range from 3 to 5 miles per hour; and also in contrast with street car and other similar service, based on a maximum speed of 8 or 10 miles.

The highest speed permissible in surface traffic in cities would be by automobile, which would be 12 miles per hour; but this maximum could not be expected in the congested streets of the business section. Hence we have in the speed attainable with the pneumatic-tube service an important factor which does not seem to be attainable in any other way.

In the early years of the pneumatic-tube service it had been apparently expected that the maximum speed of 30 miles per hour would be maintained between all points of exchange, but the present contracts in response to advertisement of June 21, 1902, merely require a speed of not less than 30 miles an hour between the general post-office and the first station, or any station and the next station. The consequence is that the maximum speed is not obtained between stations far distant from each other because of the time taken in handling the pneumatic-tube carriers at intermediate stations in transferring them from the receiver to the transmitter, and because the carriers dispatched must to a certain extent take their turns in the regular traffic of the line.

During this investigation a number of tests were made in the several cities to ascertain the actual speed by tube per hour in transmission between the general post-office and the several other stations in each city, with the following result:

It is therefore evident that when there is a long line of tubes made up of a large number of sections the speed between the extreme points is somewhat lower because of the number of intermediate relays and the exigencies of mail traffic on the line. This would be notably the case in the West Side line in New York City from the general post-office to Station L, a distance of 11.91 miles with 9 intermediate stations, on which it might be expected that in regular practice the speed between the extreme terminals would be reduced about one-third, or to about 20 miles per hour. An incidental advantage which contributes to higher comparative speed in the tube as compared with other means is the fact that the tube terminals are within the mailing rooms of the post-office, and it is not necessary to take the mail out to the dispatching platform to go through the process of checking the mail into the mail wagons, nor is it necessary at destination to go through the reverse operation.

FREQUENCY AND CAPACITY.

Previous to the introduction of pneumatic-tube service the greatest frequency of interchange between postal stations in cities appears to have been half-hourly during nineteen or twenty hours of the day. This would therefore be a frequency of about 40 dispatches in one direction, or 80 dispatches both ways daily. However, in the largest cities the number of dispatches between the general post-office and the important railway stations would be of much greater frequency than 80 per day both ways.

The frequency of wagon service both ways daily as reported during the present investigation is as follows:

The frequency provided by the pneumatic-tube service is far in excess of anything that existed before. At present the tube carriers. are dispatched on intervals of thirteen to fifteen seconds, thus making 4 dispatches per minute, or 240 per hour, which for twenty hours would be 4,800 one way, or a total of 9,600 per day. The tube system therefore provides a frequency approximately one hundred times greater than formerly utilized.

The former frequency of interstation postal service in cities. was naturally based upon (a) the number of carrier deliveries; (b) the number of collections; (c) the quantity of mail that would justify forwarding to be worked up for carrier delivery or for dispatch; (d) the amount of special-delivery mail. In New York City the number of carrier deliveries daily ranges from 6 to 9 or 10; the number of collections from 16 to 37 daily; and it has therefore been previously assumed that the half-hourly schedule for dispatch of approximately 80 trips both ways was a sufficient provision for this number of deliveries and collections.

The increased frequency would, however, be an extremely valuable advantage in connection with special-delivery mail, and a fairly important advantage in moving forward the accumulated first-class matter to give more time in the distributing centers for its preparation for delivery or dispatch.

This great increase in frequency is, however, somewhat offset by the reduced capacity of the carrying unit. The regulation screen mail wagon has a capacity of from 1,200 to 5,000 pounds. Hence it appears that while the frequency has been increased one hundred fold the relative capacity, compared with a regulation wagon has been decreased more than one hundred fold. The maximum capacity of the tube one way per hour (240 carriers each containing 9 pounds) would be 2,160 pounds, or, say, 1 wagonload per hour.

There is a great variation in the accumulation of first-class mail between one period of the day and another, but the capacity of the tube is invariable at all hours. We thus find a number of cases where the single-tube line is inadequate to carry all the first-class mail at the maximum period, although there is plenty of unused capacity at other hours when it is not needed.