in the fields of
anthropology, biology, history, geology, and technology. Copies of each
publication are distributed to libraries, to cultural and scientific
organizations, and to specialists and others interested in the different
subjects.

The _Proceedings_, begun in 1878, are intended for the publication, in
separate form, of shorter papers from the Museum of Natural History.
These are gathered in volumes, octavo in size, with the publication date
of each paper recorded in the table of contents of the volume.

In the _Bulletin_ series, the first of which was issued in 1875, appear
longer, separate publications consisting of monographs (occasionally in
several parts) and volumes in which are collected works on related
subjects. _Bulletins_ are either octavo or quarto in size, depending on
the needs of the presentation. Since 1902 papers relating to the
botanical collections of the Museum of Natural History have been
published in the _Bulletin_ series under the heading _Contributions from
the United States National Herbarium_, and since 1959, in _Bulletins_
titled "Contributions from the Museum of History and Technology," have
been gathered shorter papers relating to the collections and research of
that Museum.

The present collection of Contributions, Papers 34-44, comprises
Bulletin 240. Each of these papers has been previously published in
separate form. The year of publication is shown on the last page of each
paper.

FRANK A. TAYLOR
_Director, United States National Museum_

CONTRIBUTIONS FROM
THE MUSEUM OF HISTORY AND TECHNOLOGY:
PAPER 42

THE "PIONEER": LIGHT PASSENGER LOCOMOTIVE OF 1851
IN THE MUSEUM OF HISTORY AND TECHNOLOGY

_John H. White_

THE CUMBERLAND VALLEY RAILROAD 244

SERVICE HISTORY OF THE "PIONEER" 249

MECHANICAL DESCRIPTION OF THE "PIONEER" 251

[FOOTNOTES]

[INDEX]

[Illustration: Figure 1.--THE "PIONEER," BUILT IN 1851, shown here as
renovated and exhibited in the Museum of History and Technology, 1964.
In 1960 the locomotive was given to the Smithsonian Institution by the
Pennsylvania Railroad through John S. Fair, Jr. (Smithsonian photo
63344B.)]

_John H. White_

The "PIONEER":
LIGHT PASSENGER LOCOMOTIVE of 1851

_In the Museum of History and Technology_

_In the mid-nineteenth century there was a renewed interest in
the light, single-axle locomotives which were proving so very
successful for passenger traffic. The