A general description and preliminary results con cerning the size of the speotnum and the zenith angle distribution are presented. The M.I.T. air shower program includes three experiments: (1) a preliminary experiment performed on the M.I.T. campus (latitude 42 deg N, sea level) by means of four detectors arranged at the vertices of a square 36 m on the side. (21 The Agassiz experiment' which covers a circular area 460 m in diameter on the grounds of the Agassiz Astrononfical Station of Harvard University (latitude 42 deg N, 183 m above sea level. (3) The Kodaikanal experiment'' using four detectors at the vertices of a square 35 m on the side in operation at Kodaidanal, India (latitude 8 deg N, 2800 m above sea level). Some results concerning the size spectrum and the zenith angle distribution are preserted. The results on the arrival directions of air showers cover a range of prirnary energies from 10/sup 14/ ev to lO/sup 18/ ev and a range of celestial declinations from -30 deg to + 80 deg . Below primary energies of about 10/sup 17/ ev, the data are consistent with the hypothesis that the primary flux is isotropic. Within statistical accuracy, thismore » result is in agreement with results obtained in other experiments. On the other hand, the distribution of the arrival directions of showers with N > 3 x lO/sup 7/ recorded by the large experiment, gives evidence of a lack of isotropy in the flux of primaries with energies greater than 10/sup 17/ ev. (A.C.)« less