1147 
period the a-v-interval is again much shortened, in the then following 
period it lengthens again. 
We found thus, that heart-bigeminy after poisoning with veratrine 
can develop itself in 3 ways. 
1. as transition-stage between the normal rhythm and the halved one ; 
2. by alternating retardation in the conduct-systems between the 
different heart-partitions. 
3. with accumulations of extra-systoles after blockading of the 
connection-systems between sinus venosus and atrium. I found the 
manner of development as it is indicated by Hering only in dis- 
connected groups. I never found a row of bigeminus-groups of which 
every 2nd systole was an extra-systole. 
Geophysics. — On the relation between departures from the normal 
in the strength of the trade-winds of the Atlantic Ocean and 
those in the waterlevel and temperature in the northern European 
seas. By P. H. Gaus. (Communicated by Dr. J. P. vAN DER STOK). 
(Communicated in the meeting cf February 27, 1915). 
1. From hydrodynamical and oceanographical investigations in 
the North-Sea, the Baltic, the Norwegian and the Barents-Sea, the 
existence of the following phenomena is evident. 
a. Mean values from Dutch’), Norwegian’), German*) and 
Finnish *) tide-gauges show an annual periodicity in the waterlevel 
of the North-Sea and the Baltic, displaying a minimum in spring, 
a maximum and secondary-maximum — separated by a rather clearly 
indicated secondary-minimum — in autumn. 
6. Temperature and salinity observations of the underlayers in the 
North-Sea’*), the Norwegian’) and the Barents-Sea"), show a periodicity 
1) Koninklijk Nederlandse Meteorologisch Instituut N° 90. 
J. P. VAN DER Stok. Etudes des phénomenes de marée sur les côtes néerlandaises. 
1. Analyse des mouvements périodiques et apériodiques du niveau de la mer, 1904. 
2) H. GEELMUYDEN. Resultater af Vandstands Observationer paa den Norske Kyst. 
Hefte VI, 1904. 
8) Orro Perrpersson. Ueber die Wahrscheinlichkeit von periodischen und unperio- 
dischen Schwankungen in dem Atlantischen Strome und ihren Beziehungen zu 
meteorologischen und biologischen Phaenomenen. Rapports et Procés Verbaux du 
Conseil Permanent pour |’Exploration de la mer. Vol. HI, 1905. 
4) Rour Wirtina. Finländische Hydrographische-Biologische Untersuchungen N°. 7, 
Helsingfors 1912. | 
5) Report on Norwegian Fishery and Marine-Investigations Vol. IL, 1909, NO, 2, 
The Norwegian Sea, its physical oceanography, based upon the Norwegian Researches 
1900—1904 by BjörN HeLLAND—HANSEN and FRipTJor NANSEN. 
6) L. Brerrrusz. Oceanographische Studiën über das Barentsmeer. Petermanns 
Geogr. Mitth. 1904 Heft IL. 
