ACCORDING to a recent article distributed by Science Service, Washington, D.C., Dr. Arthur H. Compton, of the University of Chicago, proposes to use small sounding balloons that will automatically send wireless signals recording pressure and tempera ture of the air and the intensity of the cosmic rays. The idea is not new, having been developed for example by Prof. J. M. Benade, of Lahore, and by Prof. Moltchanoff, of Leningrad (NATURE, Dec. 31, 1932, p. 1006). The risks attending direct exploration of the stratosphere are obvious, and these special balloons are designed to avoid them, while greatly reducing expense; they are said not to exceed 15 ft. in diameter at release, and to weigh only 16 Ib. Radio signals are to be emitted from a single valve oscillator. The movements of a special barometer will affect the wave-length of the signals, and the signals will be interrupted by a balance wheel, of which the ratd of oscillation will be controlled by temperature. They will also be interrupted at each discharge of a cosmic ray counterâ an instrument which discharges at a rate dependent upon the conductivity of the atmo sphere, which in turn is affected by the cosmic raysâ the length of time between such breaks giving an indication of cosmic ray intensity just as the lengths of the intervals between interruptions previously mentioned will indicate the temperature. It is under stood that Dr. Compton's measurements will not entirely replace those made with manned ‘strato sphere balloons’, but will supplement them and allow some information to be obtained from sparsely populated regions where neither manned balloons nor balloons that release self-recording instruments when they burst can be employed, in the first case because of the risk of descent far from help and in the second because of the small hope of recovering the instruments.