Variations of Cosmic-Ray Intensity with Variation of Barometric Pressure and Temperature at Sea Level

Some results are given from the records of three different ionization-chambers, two under 110 cm Fe, one under 12 cm Fe. A daily influence generally parallel to temperature is found in the thin shielded instrument, not in the thick shielded one, and only in winter. It is found that the short periodic variations are not followed by the thick shielded instruments. The long periodic variation with temperature is generally antiparallel and moreover temperature and pressure variation is the same in all three instruments. A barometric coefficient of -6.4 percent per cm Hg is found and a temperature coefficient of -0.21 percent per degree C. The high value found for barometric variation is not explained, but seems not improbably to be related to the high values sometimes found at large angles from the vertical.