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 38

THE EARLIEST ELECTROMAGNETIC INSTRUMENTS

_Robert A. Chipman_

ELECTROSTATIC INSTRUMENTS BEFORE 1800 123

INSTRUMENTING VOLTAIC OR GALVANIC ELECTRICITY, 1800-1820 124

ELECTRICAL INSTRUMENTATION, 1800-1820 125

OERSTED'S DISCOVERY 126

BEGINNINGS OF ELECTROMAGNETIC INSTRUMENTATION 126

CHRONOLOGY AND PRIORITY 127

ORIGINAL ELECTROMAGNETIC MULTIPLIERS 129

CONCLUSIONS 135

ACKNOWLEDGMENTS 136

[Illustration: Figure 1.--MODELS OF VARIOUS ELECTROMAGNETIC INSTRUMENTS
created by Schweigger, Poggendorf and Cumming in 1821, made for an
exhibit in the Museum of History and Technology, Smithsonian
Institution. (Smithsonian photo 49493.)]

_Robert A. Chipman_

THE EARLIEST ELECTROMAGNETIC INSTRUMENTS

_The history of the early stages of electromagnetic instrumentation
is traced here through the men who devised the theories and
constructed the instruments._

_Despite the many uses made of voltaic cells after Volta's
announcement of his "pile" invention in 1800, two decades passed
before Oersted discovered the