Results are presented of cosmic ray measurements taken at sea level during 1954–55 from the Arctic to the Antarctic. The equipment consisted of a neutron monitor and a meson telescope. Latitude effects of 1.77 for the nucleonic component and 1.15 for the meson component were measured. The longitude effect at the equator was much less than expected on the basis of the geomagnetic eccentric dipole and the longitude effect at intermediate northern latitudes shows that the longitude of the effective eccentric dipole is considerably west of that of the geomagnetic eccentric dipole. In a previous paper by the same authors, the positions of the equatorial minima were combined with other published cosmic ray measurements to calculate a new cosmic ray geomagnetic equator. In this paper new coordinates are derived on the assumption that these equatorial coordinates apply to a new eccentric dipole, and, therefore, that the equatorial coordinates may be extended to high latitudes. When the complete results are plotted on these coordinates, it is found that an eccentric dipole representation of the earth's magnetic field is inconsistent with the combined observations at all latitudes.

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The mean annual intensity of the nucleon and meson components of the cosmic-ray intensity at Ottawa, Churchill, and Sulphur Mountain was at a minimum for the year September 1957 to August 1958 when the mean annual intensity of the 10.7-cm radio solar flux was at a maximum and the annual mean of the interplanetary magnetic index Kp was at its first maximum since the low at the beginning of the present solar cycle. At Resolute Bay the mean annual intensity of the nucleon and meson components was at a minimum for the year July 1959 to June 1960 when the interplanetary magnetic index Kp was at a second maximum. The anomalous behavior at Resolute Bay is attributed to a combination of spectral differences and directional effects.

Measurements have been taken on the changes in intensity of the nucleon and meson components of cosmic rays during a cruise of the Canadian Naval Icebreaker Labrador into the Arctic, through the North West Passage, and circumnavigating the North American Continent. The geomagnetic latitudes covered extend from 18°N. to 89°N. The latitude knee is clearly shown at a geomagnetic latitude of about 52° in the case of the nucleon component and less definitely between 40° and 50° in the case of the meson component. The rigidity of particles arriving in a vertical direction at 52° is 2.1 Bv. and at 45° is 3.7 Bv. Meyer and Simpson have shown that changes in the primary spectrum between 1948 and 1954 probably extend up to these rigidities and such changes should, therefore, be observable at sea level. The longitude effect at low latitudes is clearly shown by differences in intensity between the measurements on the east and west sides of North America. In the case of the meson component, the magnitude of the longitude effect at these longitudes was found to be greater than that shown by Millikan and Neher in 1936. The interpretation of the meson component results above the knee is complicated by difficulties in temperature correction. In the case of the nucleon component, an apparent longitude effect exists above the knee in that there was a small difference in the intensity at high latitudes in the eastern and western parts of the North American Arctic. No satisfactory explanation is offered for this. The diurnal variation of the nucleon component at high latitudes is shown but no unusual features were found. Appreciation is expressed to the Royal Canadian Navy for making these measurements possible.

The semidiurnal component of the nucleonic intensity at Ottawa, Canada, is essentially a pressure effect for the 5-year period, 1955 to 1959. The diurnal variation is composed of the component due to pressure, and a component that may be attributed to an anisotropy of the primary cosmic-ray particles. The results are confirmed by a comparative study of the data from 15 stations between the geomagnetic latitudes 83 °N. and 73 °S.A world-wide barometric coefficient of −0.72% per mb was obtained from the semidiurnal component and this coefficient was used to correct the diurnal component at all the stations. The average corrected diurnal variation during the period of study common to all stations, August 1957 to October 1958, is 0.27% and occurs at 14 h 16 m solar time. There is considerable spread in both amplitude and phase angle amongst the various stations. The root mean square differences from the mean amplitude is ±0.05% and from the mean phase angle is ±10° (40 minutes in time). The difficulty of drawing definite conclusions about the anisotropy from short-term studies of individual stations is pointed out.