During each of the two recent periods of special international coordination of scientific effort, the IGY (International Geophysical Year) and the IQSY (International Year of the Quiet Sun), we made a latitude survey of cosmic rays, using ionization chambers carried by balloons. All instruments were carefully compared with the same set of standards. In each case, simultaneous balloon flights were made from a high‐latitude base station. Such monitoring of the primary radiation allowed corrections to be made to the data from the mobile station. Ratios of the abundances of the different nuclei to that of protons in the primaries as found by other observers have been used to separate out the effect due only to protons. Two methods are used to find the differential spectrum of the protons for the different years. Above 1 bev, the areas under successive latitude difference curves are used. This method takes advantage of the earth's magnetic field as an analyzer. Below about 0.6 bev the ranges of protons in air and areas are used. The two methods give results that are consistent with each other. Where applicable the results are also in good agreement with the differential spectra of protons found by other observers using satellites and high‐altitude balloons. From the integral of the differential spectra so derived for the different years, it is found that the total number of primary protons increased by a factor of 3.1 between 1958 and 1965. From similar flights made during the previous solar minimum the change from 1954 to 1958 is found to be a factor of 4.2. This, as well as solar activity data, indicates that there was more residual modulation of the primary cosmic radiation during the 1965 minimum than was present in 1954.