chapter I

have given a brief sketch of what has been done in the application of pneumatic tubes from the earliest records to the present time. The second chapter contains a description of the postal tubes in Philadelphia, and the third chapter describes our system in detail. Following this is a short chapter explaining the theory of pneumatic tubes, or the theory of the flow of air in long pipes, stating the more interesting facts and relations in as plain and simple a manner as possible. Mathematical formulæ have been purposely avoided.

Several plates showing the Philadelphia postal line have been kindly loaned to me by the Engineers’ Club of Philadelphia. They formerly appeared in a paper read by Mr. A. Falkenau before that club. I have also to thank the and Drill Co., the B. F. Sturtevant Co., the Wilbraham-Baker Blower Co., and J. B. Stewart for the use of electrotypes of their machines.

B. C. B.

October 6, 1896.

THE

BATCHELLER PNEUMATIC TUBE SYSTEM.

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