Year: 1874

ARCHIBALD SMTu..The death Of Archibald Smith
on the 18th OF December 1872, has been followed by
an obituary notice published in the Proceedings of
the Royal Society for February 1874, from which is
here obtained connected view of the very import
ant researches which form his main contribution TO
science viz. his stldy into the phenomena of ships
magnetism About the year 1871 his attention was
drawn to this problem by bis friend Major Sabine,
and lie shortly after published solution of the
questions connected with this subject in "A form far
more readily understood than had previously been
given by Poison The formulae of Mr.. Smith sup
piled the means of sufficiently exact calculation of
all the laws affecting he accuracy of the compasses
on board of any wooden vessel aud when reduced
TO simple tabular forms, they were at once adopted
by the Admiralty aud have ever since continued to
be used in the Royal navy. As tue use of iron i'll
vessels increased, and the weight of the armament
OF ships-Of-war increased the irregularities Of the
compass to incOnvenicnt degree. an entire revi-
sion of the old Admiralty instructions became neces-
sary and the mathematical part OF the work was
intrusted to Mr.. Smith. That gentleman reduced
the complete expression given by Poison, calculating
the effect of both the permanent and the induced
magnetism of the iron portions Of the vessel to a
few simple and easily applied formue. and this last
edition of the Admiralty Compass Manual has been
translated into numerous languages and adopted by
the United States the Russian, German, Portuguese
and French. The rule given by Smith for placing
the needles on the compass cards mas been adopted
by every nation. 1t reads thus


When there needles used they should be placed
with the ends tue card at CO. ON eaeh side
OF the ends OF diameter; and wien there are four
needles they should placed with their ends AT l5o and
450 distance FROM the ends OF the diameter.


The reasons given for this rule by Smith when it
was originally proposed were afterward supple
mented by various important merits which were
found TO be incident to this construction Of the card


The general tenor of Mr. Smiths researches as well
as the result of all the experience of the British
navy, seems to show that COMPASS needles (which


have sometimes attained to the monstrous length of


10 inches or even more of the great modern
passenger steamers) ought by no means 10 be so
| large as they are generally made; that i'm fact


seven inches long should be the limit in length and


that il shorter than this the of the needle will


be still more perfectly corrected. In fact when the
needles of the standard compass are reduced to
| something like half inch in length and not till
then, will the theoretical perfection, and beauty


and great practical merit OF Airys method of cor
recting the compass be universally recognized and


have full justice done TO II III practice The studies
| of Archibald Smith III relation To compass deva-
tons carried by him a labor of love en-


tiIely distinct from hls practice OF law. He gradI-


ally attained TO an important and extensive prac-
tice and TO high reputation as chancery barris-


but never lost his interest ia science ceased


10 be engaged IN scientific pursuits. la addition 10
tie love Of science for It's own sake he was Dcne-