128 



K. YE. Veselov and V. L. Panteleyev 



Let us assume that the ampHtude of the vertical accelerations is 5 gal, and 

 their oscillatory period 10 sec. In this case the gravimeter pendulum will 

 oscillate with an ampUtude of 5x0.0061 = 30 mgal. 



The above gives rise to certain assertions. 



Firstly, under conditions of strong damping, , small sinusoidal vertical 

 accelerations do not produce systematic changes in the gravimeter read- 

 ing but on]y forced sinusoidal oscillations in the pendulum, the amp- 

 litude of which is decreased proportionally to the value of A. The ampUtude 

 of the vertical accelerations can be found from the recording of these 

 oscillations. 



Secondly, it is not necessary to wait for the system to come completely 

 to rest in order to take readings from the instrument. The reading for a posi- 



tion of static equilibrium of the system may be calculated from the recorded 

 motion of the pendulum, thus considerably reducing the amount of time 

 spent in observations at the point. 



Thirdly, the dynamic coefficient which, for a given oscillatory frequency 

 of the vessel, is the basic parameter of the gravimeter can be found from 

 the recorded motion of the gravimeter pendulum when deflected from a state 

 of equilibrium. 



Apart from the methods of measurement and the determination of the 

 instrumental parameters, the problem of the combined effect of vertical 

 and horizontal accelerations and inclination on the instrument readings 

 is of considerable relevance to the static method of measuring gravity at sea. 



We shall attempt to solve the problem to the first degree of approximation. 



It is assumed that the instrument is mounted on a Cardan suspension 

 subjected to vertical and horizontal accelerations so that the suspension 



