American citizen. [volume] (Canton, Miss.) 1864-1890, 1878-11-30
AMERICAN DISPLAY AT THE
PARIS EXPOSITION. f;.iaus,-
wonders of the Mechanical DEPART
as ment.
From the London Times, Aug. 0.I


From the London Times. Aug. I'll
Perhaps, however,. the most inn
portan. display in this department, all tnings
considered, is that of the Waltham Watcn
Company, their first in the European exhipi-
tions. The readers of the Times reports, OF
the Philadelphia Exhibition will not need 70
be informed of the admirable machinery py
which the works OF the Waltham Watcnes ais
produced, or their singular exactitude, which
enables any part of a watch to be repiaceo py
the corresponding piece of any other watch Oh
the same grade. In this mechanical prouuc-
ton of machines, America has long leo Inc
world and the mechanism by which the En-
glish army rifle is still produced is with I'M
material notifications contribution from
works science has been brought to he
aid of native ingenuity to such degree that
even since the Philadelphia Exhibition the
fabrication of watches has gone through
large arc of another revolution. What was
begun by applying such machines that their
work was beyond competition on anything
like equal terms from any hand-woFk is con
tinued by the construction OF the most esse eis
tial parts of watch on a new principle, winch
permits an approach to periection unattaIF
able by the old mechanism, however pro-
iuced. Every one knows that the great diin-
Guilty in making chronometers mas Leen a am5
contraction due to change OF tennperatuI3s'
but what is less well known is that TINS uiin-
Guilty is due less to the balance, which pS us
construction with bi-segmental rim (oI BRASS
and stceD, may be perfectly corrected, liian
to the expansion OF the balance or hair
spring, which, being immensely longer cruises
five times the error caused by the exph us To
or contraction balance-wheeI alone. uo
two Iieces must be considered as ohe,
and the compensation effected in the wneei
. or j i'm must answer for the spring as wen As
for itself. The theoretical ana ifisuperaoie
difficulty in this compensation has always been
that the error caused by the expansion anu
contraction of the spring was In dIereht
ratio from that of the correcting expansion OF
be compared to curves with two radi, whlcn
could be brought together at two points, buI
not to coincide throughout, SO thatll tle com
pensation at the extremes OIL Temperature 10
correct, the mean must be in error and pace
yeYsd
The old compensation WAS speaking broad
ly, in brazing band OF brass on one OF steSi,
a process both theoretically and mechanically
erroneous, since the contraction and eXpan-
sion can only go ON with a certain tendency 10
disrupture OF the elements aud consequent IN
equality of the action; Inc new naia,lee pr of
the compensating metals The rim, OF PLAIN
steel, is cut nearly through at the hxed ex,
tremities of the semi circles by several
saw-tooth shaped notches, the number de-
termined by experiment, and the brass Is
forced into these notches. The compensat-
ing weights are then put on at tie otner
extremities of the sem-circles instead OF be-
ING distributed along them empiricaliy, and it
isfound possible in this arrangement 50 10 uis-
tribute the compensation and compromising
weights as to give at viii a compensation Ior
the mean Temperature, either in excess OF, or
less than the extremes and OF course, to give
a compen sation which shall coincide through
out, which makes it theoretically possible to
give absolute compensation Tor all tenpera-
lures at once. 1t is difficult to make TINS
clear, without diagrams showing the exact
curves attained by experiment; but the nature
of the result will be appreciated by those VINO
know the mechanism of the balance. IL Is
simply the theoretical elimination of all error
from the compensated balance so far as tenn
perature is concerned. Practically aud me
Chemically there will always be some, due to
the inherent imuerfecton of human workman
ship; but il is believed that the mean error. AND
| equally the manual adjustment required VIII De
reduced to one third of that actually obtaining
\ under the old form of balance. Butte illustrate
| how involved are the various improvements IN
| mechanism it may be noted that the delicacy oi
| construction OF the new balance would only
| have been possible with the mechanism intro
| duced by the Waltham Company, the precision
| of which may be judged from that OF the mi
crometer last produced and shown at Paris
which measures the nty-fve-thousandti
part of an inch, and even indicates that sc
| largely that it might be divided under len'
readily into hundred thousandths. mi
/ crogneter screw gauge detects Inequalities IL
the thread of screw up to hundred thou
/ saudtLs and a screw made for the Severn
/ mcnt Scientific Commission To correct tii
| measures has been constructed i'll which th'
maximum Of error in the thread is less than On
ten thousandth part OF an inch