( 278 
27 and 28 had lately been cleaned, while Strasser 95 during the 
period of observation had twice been replaced and meanwhile had 
been exposed to great differences of temperature. For DeNcKer 12 
at =Leipzig also some perturbations from outside shortly before and 
during the period under consideration are noted. 
7. For a clock which is used for astronomical fundamental deter- 
minations the regularity of the rate during the 24 hours of the day 
is of the very highest importance, but it is obvious that only long 
continued observations reduced with the greatest possible care can 
give us any information on this subject. 
As yet I can only state that we may confidently expect Honwt 
17 not to be inferior in this respect to other clocks kept at constant 
temperature, seeing that, while the amplitude of the yearly variation 
of temperature has diminished comparatively little in its present 
place, the daily variation has almost entirely disappeared. 
This will be seen from the following values of the difference 
between the temperature at 4 o'clock in the afternoon and the mean 
of the temperatures of the preceding and the following 8 hours in 
the morning. These differences taken for about 240 days have been 
combined in 6 two-monthly groups, and their means follow here: 
Temp. 4h—Temp. 20h 
damuary, PELI LI ee oes cee oe: + 0?.09 
MENGEN; Api er ten ot EE mains + 0.15 
Baty. JUNG oy rae iit eet tot eee + 0.12 
A RY AMD ECs zn ar Ms ic OEE ay + 0.20 
September, Outabereee aoe. ee a Chee 
Rotan bet, Deerns hae wee + 0.08 
The mean difference is greatest in summer, but even then very 
small, while no difference ever reaches to 07.5. 
(October 22, 1902). 
