Smithsonian Institution

Produced by Chris Curnow, Tom Cosmas, Joseph Cooper and

the Online Distributed Proofreading Team at

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Transcriber's note:

This is Paper 41 from the _Smithsonian Institution United States

National Museum Bulletin 240_, comprising Papers 34-44, which will

also be available as a complete e-book.

The front material, introduction and relevant index entries from the

_Bulletin_ are included in each single-paper e-book.

Italic emphasis denoted as _Text_.

Whole numbers and fractions: shown as 1-1/2, 3-1/4, etc.

Please see the end of the book for corrections and changes made.

Smithsonian Institution

Tunnel Engineering: A Museum Treatment · 第 1 / 42 题