whilst for that of the small tide P the circumstances will be un¬ 
favourable always and everywhere. 
2. In a recent publication 1 ) Prof. Hecker has made an investigation 
of the influence of forces generating tides on two horizontal pendu¬ 
lums set up for this aim in a pit so that the influence of changes 
m temperature was reduced to a minimum. 
. The r ? ult of thls investigation surpasses the expectations about 
the possibility of such a determination of disturbances of gravity 
caused by celestial bodies which were until a short time ago decidedly 
unfavourable. J 
The two instruments are not of equal value; the pendulum set 
up in an azimuth of 222* proves to be a much better instrument 
than the other; the results obtained with the best pendulum are, 
expressed m deviations of an equivalent vertical pendulum in arc 
seormns 
M l Calculated 0".00922 cos (2 t — 305°.5) 
* I Observed 0".00622 cos (2 t — 285°4) 
5 I Calculated (T00399 cos (2 t — 305°.5) 
’ I Observed 0".00244 cos (2 t — 273°.6) 
Deviations in the sense of the movement of the hand of a time¬ 
piece are reckoned positive for this instrument. 
Hecker concludes from this that the earth deforms itself under the 
riTd°f \ f0rC0S 0f the tides and * hat ite rigidity or resistance 
against deformat.on is about equal to that of a steel sphere. This 
result is in accordance with the conclusions drawn from the variation 
1 vel rjf f P ro P a S a tion Of the first forerunners of a seismic 
wave (longitudinal vibration) from 7 to 13 K. M. and of the second 
forerunners (transversal vibration) from 4 to 7 K. M. with the depth 
of the layers passed through and likewise with the fact that the 
principal periodical oscillation of the geographical latitude does not 
pIa h Ce . m a P eriod of 306 d ' (E™*) but of 427 d. (Chandler), 
naTeV ahn 7 T* ! g-ater resistance agains, deformation 
namely about twice that of steel. 
deduce he J aSt iL ChaP a er HECKEE diSCU8SeS in short * he Possibility to 
7“ ' . from the data tne influence of the partial tidal force 7 
lurnal periodical with sidereal time; here however he is checked 
dfurnal 6 7. men(ioned difficnlt y that CTi dentIy there exists in the 
anTnnuaTval C t r Vement ^ ° f ““cal origin, 
Er^pers 'ZZ “s H ° riZ “ ta 'r de ' n flber die Defonuatiou des 
Gedd. L. Neue 32,7m ”” “ M ° nd ' ““ deS ^ 
1 * 
