There is a discrepancy in the electron excitation cross section for electric quadrupole transitions between Sneddon and Touschek, who obtain essentially the same result for both electric quadrupole and magnetic dipole transitions, and Wick. We have also calculated this and agree with Wick's result. TABLE I. Hourly rate of coincidences.

A preliminary analysis of cosmic‐ray neutron monitor intensity data during the November 1960 solar disturbances is presented. The first increase on November 12 is attributed to generation of particles on the sun, following a class 3+ flare. A second increase on November 12 is interpreted as the arrival at the earth of solar particles trapped in the gas cloud emitted by the sun in connection with a previous flare. It is shown that the arrival of a further cloud sweeps away the remaining solar particles. The increase on November 15 is attributed to a new generation of high‐energy particles by another class 3+ flare that occurred on the same solar active region. The characteristics of the solar flare increases are shown to agree with the conclusions of McCracken and Palmeira regarding the propagation of solar particles in interplanetary space. Data from low latitude stations are used to investigate the Forbush decreases and their relation with other solar and terrestrial events.

T HE energy of the Y-rays emitted by natural radioactive K 40 was measured by the absorption method, with copper and lead used as absorbers. We found an energy of 1.5 Mev in accord with the value 1.54 Mev obtained by Warner and Hirzel. 1 This energy, however, is a little higher than the upper limit 1.35 Mev of the continuous /3-spectrum 2 and so it seemed difficult to associate this 7-ray with the /3-transitions. On the other hand, positron emission or i£-capture could take place to account for the great abundance of A 40 . Evidence for a i£-capture process was given 3 recently, and no positron activity has been detected. We undertook fi-y coincidences to show that the 7-rays should be associated with the i^-capture process. Measurements were taken with a precision of 1 percent, and no coincidences were obtained. These experiments show that no 7-rays can be associated with the ^-transitions and that, therefore, the nucleus of Ca 40 is not left in an excited state, showing that the disintegration scheme proposed by Warner and Hirzel is a correct one.

about 15/1, while the corresponding ratio of meson intensity is only 2/1.Hence we may say that it appears almost certain that high energy nucleons and

The mean range of the radiation that generates penetrating showers has been determined in the atmosphere and in water. The results are respectively ^120 g/cm 2 and ~55 g/cm 2 . The relation between the observed variation of the frequency of penetrating showers with barometric pressure and the absorption law in air for the shower producing radiation has been discussed in some detail. The east-west asymmetry of the radiation that generates penetrating showers has been studied and the results were found to be negative within the experimental errors. The penetrating power of the penetrating showers produced in air has been investigated. No appreciable absorption has been found when the lead protection of the counters has been increased from 18 to 28 cm.