In the preface to his 1842 Manual of Magnetism, the Boston scientist and manufacturer of electrical apparatus, Daniel Davis, Jr., wrote, “Magnetism and Electricity have become related sciences within such a short a period, and their growth has been so rapid, that many important facts which have been observed have not been collected in any scientific treatise, and the amount of unwritten knowledge has been constantly increasing.” His book served as a companion to the apparatus that he manufactured, and it supplied the scientific background to experiments using these instruments. This paper traces the development of some of these instruments and explains their operation, showcasing their ingenuity and inspiring demonstrations for contemporary physics classes. A great deal of his apparatus still exists in museums and the storage closets of schools, college, and universities. I urge you to seek it out and husband it.

1.
The birth dates are: (
1809
)
N. B.
Chamberlain
and
Benjamin
Pike
, Jr.
; (
1811
)
James W.
Queen
; (
1812
)
Joseph M.
Wightman
and
Davis
; (
1814
)
Edward S.
Ritchie
.
2.
The biographical material about Davis is drawn from his obituary
,”
Sci. Am.
56
,
256
(
1887
).
3.
Daniel
Davis
, Jr.
,
Davis's Descriptive Catalogue of Apparatus and Experiments, to Illustrate the Following Branches of Sciences, Namely: Galvanism, Electro-Dynamics, Magnetism, Electro-Magnetism, Magneto-Electricity, Thermo-Electricity
(Daniel Davis, Jr.,
Boston
,
1838
)
4.
Daniel
Davis
, Jr.
,
Davis's Manual of Magnetism
(Daniel Davis, Jr.,
Boston
,
1842
)
5.
Daniel
Davis
, Jr.
,
A Manual of Magnetism
, 2nd ed. (Daniel Davis, Jr.,
Boston
,
1848
)
6.
Thomas B.
Greenslade
, Jr.
, “
Galvanometers
,”
Phys. Teach.
35
(
7
),
423
426
(
1997
).
7.
On some new electro-magnetical motions, and on the theory of magnetism
,” reprinted in Michael Faraday,
Experimental Researches in Electricity
(Bernard Quaritch,
London
,
1844
), pp
127
147
.
8.
Electro-magnetic Rotation Apparatus” and “Description of an Electro-Magnetical Apparatus for the Exhibition of Rotary Motion
,” Ref. 8, pp
147
151
9.
Peter
Barlow
, “
A curious electro-magnetic experiment
,”
Philos. Mag.
59
241
242
(
1822
).
10.
John
Daffron
and
Thomas B.
Greenslade
, Jr.
, “
A non-toxic Barlow's Wheel
”,
Phys. Teach.
53
,
42
43
(
2015
); A modern reference is
Thomas B.
Greenslade
, Jr.
, “
Apparatus for natural philosophy—Barlow's Wheel
,”
Rittenhouse
1
,
26
8
(
1986
)
11.
Joseph Hale
Abbot
, “
A description of several new electro-magnetic and magneto-electric instruments and experiments
,”
Am. J. Sci.
40
,
104
111
(
1841
).
12.
Robert C.
Post
,
Physics, Patents and Politics
(
Science History Publications
,
New York
,
1976
).
13.
Charles G.
Page
, “
Electro-magnetic apparatus and experiments
,”
Am. J. Sci.
33
,
190
192
(
1838
).
14.
Reference 13, p.
191
.
15.
Benjamin
Silliman
, Jr.
,
Principles of Physics
, 2nd ed. (
Ivison, Blakeman, Taylor, & Company
,
New York
,
1860
), p.
611
.
16.
Charles G.
Page
, “
Magneto-electric and electro-magnetic apparatus and experiments
,”
Am. J. Sci.
35
,
252
268
(
1839
).
17.
Reference 18, pp
264
265
.
18.
Daniel
Davis
, Jr.
,
A Manual of Magnetism
, 3rd ed. (Boston,
1851
).
19.
Reference 6, pp.
288
289
.
20.
Reference 6, pp.
289
290
.
21.
Reference 18, pp.
258
259
.
22.
Roger
Sherman
, “
Charles Page, Daniel Davis, and their electromagnetic apparatus
,”
Rittenhouse
2
,
34
47
(
1988
).
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