Scientific American Supplement No. 822, October 3, 1891 — John Shaqi
Scientific American Supplement No. 822, October 3, 1891Various
Science
Scientific American Supplement No. 822, October 3, 1891
Various
Science -- Periodicals
(7) That for the purpose of replacing the standard, if lost,
destroyed, or damaged, and for ordinary use, a limited number of
copies should be constructed, which should be periodically compared
with the standard ohm and with the British Association unit.
(8) That resistances constructed in solid metal should be adopted as
Board of Trade standards for multiples and sub-multiples of the ohm.
(9) That the standard of electrical current should be denominated the
ampere, and should have the value one-tenth (0.1) in terms of the
centimeter, gramme, and second.
(10) That an unvarying current which, when passed through a solution
of nitrate of silver in water, in accordance with the specification
attached to this report, deposits silver at the rate of 0.001118 of a
gramme per second, may be taken as a current of 1 ampere.
(11) That an alternating current of 1 ampere shall mean a current such
that the square root of the time-average of the square of its strength
at each instant in amperes is unity.
(12) That instruments constructed on the principle of the balance, in
which, by the proper disposition of the conductors, forces of
attraction and repulsion are produced, which depend upon the amount of
current passing, and are balanced by known weights, should be adopted
as the Board of Trade standards for the measurement of current,
whether unvarying or alternating.
(13) That the standard of electrical pressure should be denominated
the volt, being the pressure which, if steadily applied to a conductor
whose resistance is 1 ohm, will produce a current of 1 ampere.
(14) That the electrical pressure at a temperature of 62 deg. F. between
the poles or electrodes of the voltaic cell known as Clark's cell may
be taken as not differing from a pressure of 1.433 volts by more than
an amount which will be determined by a sub-committee appointed to
investigate the question, who will prepare a specification for the
construction and use of the cell.
(15) That an alternating pressure of 1 volt shall mean a pressure such
that the square root of the time average of the square of its value at
each instant in volts is unity.
(16) That instruments constructed on the principle of Sir W. Thomson's
quadrant electrometer used idiostatically, and for high pressure
instruments on the principle of the balance, electrostatic forces
being balanced against a known weight, should be adopted as Board of
Trade standards for the measurement of pressure, whether unvarying or
alternating.
We have adopted the system of electrical units originally defined by
the British Association for the Advancement of Science, and we have
found in its recent researches, as well as in the deliberations of the
International Congress on Electrical Units, held in Paris, valuable
guidance for determining the exact magnitudes of the several units of
electrical measurement, as well as for the verification of the
material standards.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account