fers in only minor particulars from that of M. Schweigger." On
comparing figure 7 with figures 3, 4, or 5, the remark seems overly
generous.

The history of the multiplier instruments has had its fair share of
erroneous reports and misleading clues. A fine example is the
illustration of figure 8, taken from what is often quoted as the first
report in English on Poggendorf's "Galvano-Magnetic Condenser."[31] The
sketch is the editor's interpretation of a verbal description given him
by a visiting Danish chemist who, in turn, had received the information
in a letter from Oersted. It incorporates, faithful to the description,
a "spiral wire ... established vertically," with a needle "in the axis
of the spiral," yet by misunderstanding of the axial relations and of
the ratio of length to diameter for the coil, a completely meaningless
arrangement has resulted. The confusion is compounded by the specifying
of an _unmagnetized_ needle.

Schweigger and Poggendorf, through their editorial positions, were among
the best known of all European scientists for several decades. On one
basis or another their reputations are firmly established. Comparison of
the accounts of the early "multipliers," however, suggests that the
Reverend James Cumming, professor of chemistry at the University of
Cambridge, was a very perceptive philosopher. This was well understood
by G. T. Bettany who wrote in the _Dictionary of National Biography_
that Cumming's early papers "though extremely unpretentious," were
"landmarks in electromagnetism and thermoelectricity," and concluded
that: "Had he been more ambitious and of less uncertain health, his
clearness and grasp and his great aptitude for research might have
carried him into the front rank of discoverers."

ACKNOWLEDGMENTS

I wish to thank Dr. Robert P. Multhauf, chairman of the Department of
Science and Technology in the Smithsonian Institution's Museum of
History and Technology, for encouragement in the writing of this paper
and for the provision of opportunity to consult the appropriate sources.
To Dr. W. James King of the American Institute of Physics, I am grateful
for many provocative discussions on this and related topics.

FOOTNOTES:

[1] A. VOLTA, "On the Electricity Excited by the Mere Contact of
Conducting Substances of Different Kinds," _Philosophical Transactions
of the Royal Society of London_ (1800), vol. 90, pp. 403-431.

[2] Some little-known but delightful o