180 YEARS OF

arely ever needed, Longines wanted the best of all possible
solutions. is watch movement was certainly the
best that the market had to oer at that time.
LARGER SIZE, GREATER ACCURACY
In 1938 Longines developed a chronograph that was specially
designed for use at major sporting events. For the
design of the giant 24-lignes (54.14-mm) movement,
Longines’s engineers took the highly accurate Cal. 24.99
from 1908. Longines had achieved great notoriety at
chronometer competitions in Neuchâtel, Kew-Teddington
and Washington D.C. with this movement. From the
very beginning, exibility was emphasized in upgrading
its mechanics. e chronograph was introduced in 1939
in a basic version with a semi-instantaneous 30-minute
totalizer that measured elapsed time to the exact 1/5 of a
second, thanks to its large screw balance that oscillated at
a frequency of 2.5 hertz. Its intended use at sports competitions
made the split seconds indispensable. However,
Longines’s engineers decided against placing the
mechanism on the back of the movement. Instead, they
positioned the column wheel, braking lever, splitseconds
wheel and its operating lever directly on the
front of the plate. is made the long, very delicate splitseconds
arbor no longer essential, but servicing the
watch required the removal of the hands and dial. An advanced
feature of this chronograph rattrapante with two
pushers was a hack mechanism to ensure precise setting
to the exact second. Variations with a smaller balance
and a frequency of ve hertz accurately recorded time intervals
to the 1/10 second but did not show the time. is
was also the case with the chronograph that measured
the smallest time interval, which was produced well into
the quartz era of the 1970s. In this case, the 1/100-second
measurement was possible thanks to a balance frequency
of 50 Hertz.
The split-seconds chronograph
based on Cal. 19.73N was
certainly THE BEST that the
market had to offer at that time.
Hand-wind Cal. 262
with split-seconds
function, diameter =
24 lignes, height =
14.55 mm; 36,000
vph. Production
began in 1966.
Elapsed Time | CHRONOGRAPHS
Even though Longines revolutionized the timing of
sporting events in 1954 with its quartz-controlled photo-
nish system “Chronocinégines,” the company continued
to manufacture mechanical pocket chronographs.
Ocial timekeepers placed their trust in these instruments
because of their proven reliability and precision
and could not put their full condence behind modern
electronics, always relying on back-up timers. For this
reason Longines developed the 24-lignes split-seconds
chronograph again in the 1950s, which produced the
large, technically complex Cal. 260 in 1957 that could
time events accurately to a 1/10 second. In contrast to the
previous model, the added feature for the rattrapante was
again placed on the conventional side of the movement,
the back. Its most unusual feature consisted of the rotational
speed of the chronograph and its split-seconds
hands. Only 30 seconds – not 60 – were needed to circle
the dial, and that allowed for a wider and more precise
scale. However, timekeepers were unhappy with the
modied dial design. Precise reading of elapsed intervals
was possible only in conjunction with the contrasting
LONGINES SPECIAL WatchTime | 43