- 
Miscellaneous Intelligence. 497 
III. MisckELLANEOUS SCIENTIFIC INTELLIGENCE. 
1. Concours National de at eng de Seats eee 
pour les températures ; by G. CettmrieR. Geneva, 1885.— 
competition, the results of Thich are discussed in this volume oe 
initiated by the section of Horology of the Society of Arts, 
Geneva. Fifty- -four pocket and seven marine chronometers were 
in the competition, and an SH. Sapp marine chronometer was 
added for purposes eH compariso 
It is well known that a serotonin with an sneer maf 
balance wheel may te regulated to keep time for any one given 
temperature. With a compensated balance ete the chronome- 
ter can be regulated to keep correct time at any two given 
temperatures. But experience shows that, in general, the chro- 
nometer thus hs pte will not mF correct time at other temper- 
atures than those two. Fifty years ago Dent expressed this by 
saying: that etweun the two ive temperatures the chronom- 
eter gains time, that above the higher and below the lower 
temperatures the chronometer loses time. This secondary error 
of compensation, or Dent’s inequality, is sometimes expressed 
thus: Zhe curve whose abscissas are the temperatures and whose 
ordinates are the sponding rates is a parabola. A goodly 
f mechanical devices have been tried, at large expense 
of time y, generally with indifferent success, for th 
* * 
say the present investigation is, we believe, the first extensive 
one for ascertaining the facts about this inequality. It gives us 
a large number of observations. M. Cellérier has obtained from 
them some important conclusions. 
S chronometers had steel spiral springs and some had 
palladium. The whole were kept at a ee as near to 5° 
Centigrade as practicable for five days, then in like manner for 
successive pope of ie Rpts each, the remperacar es were 10°, 
1 0°, 20°, 35°, 25°, 20°, 15°, 10°, 5°, 35°; that is, 
fourteen’ sete in all. Boewéen each two periods one day was 
omitted to allow the warm box and the time-pieces to assume 
Sa= the new ay! beer In the final porugres se last 
r 
secondary error. But the principal scientific interest of the wor 
sig ain in the facts and discussions about the secondary — y: 
e pieces that had palladium hihi were compared with 
those that had steel springs, with the following results. Upon 
plotting the curves to present the observed secondary error those 
Ww 
mo 
nclined to a parabolic form, but had greater amplitudes 
shot, steel springs in the hands of a good adjuster permit us to 
