Cosmic Radiation at Very High Altitudes Near the Geomagnetic Equator

During an extensive series of balloon-flights near the geomagnetic equator in India, intensity-depth curves have been obtained with the standard quadruple coincidence counter trains, containing various thicknesses of interposed absorber (4.0 cm, 7.5 cm, and 17.7 cm of Pb), previously utilized at high latitudes. A rather pronounced difference occurs between the two stations at Aligarh, Uttar Pradesh ($\lambda =18\mathrm{}°$N) and Bangalore, Mysore ($\lambda =3\mathrm{}°$N). The primary flux values, extrapolated to the "top of the atmosphere" from data obtained with instruments containing 7.5 cm of Pb, are 0.032±0.001 and 0.024±0.001 ${\mathrm{cm}}^{-2\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ ${\mathrm{sterad}}^{-1\mathrm{}}$, respectively.