The latitude effect for cosmic-ray showers

Cosmic-ray observations have been taken with Geiger counters on a voyage from San Francisco to Colombo via Japan and return via Australia. The apparatus used possesses some interesting features and is described at length. The latitude effect for vertical coincidences is found to be 14.5 percent in the region of the Dutch East Indies and 10 percent in the Pacific Ocean. The showers show a much smaller variation with latitude, only about 6 percent being found in the region of the East Indies. This result is interpreted as meaning that the latitude sensitive part of the radiation is not as efficient at producing showers as the nonlatitude sensitive radiation. Qualitatively at least, such behavior is consistent with the hypothesis that the latitude sensitive radiation is due to incoming electrons