( 211 ) 
The frequency of the Pulsations was tested in vain like that of 
the Spasms for a concordance with the tropical or synodical revo- 
lution of the Moon. 
In the yearly values of the- frequency of these Pulsations no 
parallelism with the numbers for the sun-spots can be found, and 
in the monthly values a not very distinct yearly undulation appears, 
which however is quite different from that of the Spasms. But, 
curiously enough, the daily variations in the frequency agree, without 
being however quite equal, as appears from the following table of 
the epochs of the maxima ete. 
Spasms Pulsations 
Principal maximum  11—12 P.M. 0—1 AM 
» minimum 7— 8 AM. 7—S A.M. 
Secundary maximum + 2 EAN [eee op | P.M. 
» minimum 6— 7 P.M. 5—6 P.M. 
The Electrograms at Batavia show nothing remarkable during 
the occurrence of Pulsations, which means that no simultaneous 
changes in the Potential can be observed. As regards the slope of 
Electric Potential in the lower strata of the atmosphere, I think 
this will not have any influence on the magnet. 
In concluding this preliminary communication I will point out, 
that a magnetic calm favours the development of the Pulsations, 
which is connected directly with the quiet of night, as shown by 
the magnetograms at Batavia. This nightly calm is clearly indicated 
by the diurnal variation of the above mentioned ,deviations”, and 
the epoch of the minimum (1 A.M.) practically coincides with the 
maximum epoch of the Pulsations. But also the minimum epoch of 
the deviations (3 P.M.) coincides with the epoch of the secondary 
maximum, and this makes the connection less clear. 
Physics. — Dr. Fritz Hasenorury. “The dielectric-coef ficients 
of liquid nitrous oxide and oxygen.” (Communication N°. 52, 
from the Physical Laboratory at Leyden by Prof. H. Kamer- 
LINGH ONNES). 
(Read September 30th 1899). 
Measurements of the dielectric-coefficients of liquid gases have 
been made up to the present only by LiNpe !) and by Dewar and 
1) Lanpe, Wied. Ann. 56 p. 546. 
