Magnetic Field Measurements near Mars

During the encounter between Mariner IV and Mars on 14-15 July, no magnetic effect that could be definitely associated with the planet was evident in the magnetometer data. This observation implies that the Martian magnetic dipole moment is, at most, 3 x 10(-4) times that of the earth.

Mariner II: Preliminary Reports on Measurements of Venus: Magnetic Field

Mariner II magnetometer data gave no indication of a Venusian magnetic field. This implies, by comparison with spacecraft measurements near Earth and with theoretical models, that the magnetic dipole moment of Venus is at most 1/10 to 1/20 that of the earth.

Interplanetary Magnetic Fields

Preliminary analysis of Mariner II magnetometer data indicates a persistent interplanetary field varying between a least 2 and 10 gamma (1gamma = 10(-5) gauss). The interplanetary field appears to lie mainly in the ecliptic plane, although there is a substantial, fluctuating, transverse component. The Mariner II data agree reasonably well with the prior Pioneer V observations. Typically, variations as large as 5 to 10 gamma in the field component radial from the sun are measured. Correlations with the Mariner II plasma measurements have been observed.

The Influence of Meteorological Conditions on Rainmaking in the Sydney Area

An analysis is presented of the results of 88 flights whose purpose was to carry out rainmaking experiments, using dry ice, in the Sydney area between January 1948 and June 1950. The chance of encountering clouds suitable for rainmaking is shown to be correlated with the synoptic situation, the water content above the freezing level, the height of the freezing level, and the lapse rate below lt. The number of days on which rainmaking was possible in the Sydney area is estimated as 45, 33, and 8 for 1948, 1949, and January to June 1950 respectively, a smaller number of opportunities occurring when the natural rainfall was abnormally high. The possibility of forecasting days suitable for rainmaking is examined.

Observation of Precipitation with an Airborne Radar

A radar set with its beam directed downwards has been mounted in an aircraft and used for observation of natural and artificially induced precipitation. It provides information on where the precipitation originates within a cloud and the way in which it grows. A measure is obtained of the area and duration of precipitation reaching the ground, and an estimate of the precipitation rate. As an example of the use of this equipment, an account is given of a typical experiment in which precipitation was artificially induced by seeding a cloud with dry ice.

The Artificial Stimulation of Precipitation by Means of Dry Ice

In experiments carried out near Sydney, supercooled water clouds were " seeded " with ice crystals by dropping pellets of solid carbon dioxide into them. Up to August 25, 1948, 20 experiments were made under conditions sufficiently well defined for the experiments to be significant. In 15 of them precipitation is believed to have been released artificially. Of 11 clouds with tops colder than -7�C., 10 precipitated. The depth of the treated clouds ranged from 1000 to 15,000 ft. In none of these did natural precipitation occur within 20 miles. Further evidence that the effect is genuine is given by the fact that both the likelihood of success in inducing precipitation and the time between treatment of the cloud and the appearance of precipitation at its base, varied consistently with the cloud characteristics. The observations are consistent with the view, as postulated by Bergeron, that the precipitation grew from ice crystals (formed by the dry ice pellets).

Experiments in Seeding Cumuliform Cloud Layers with Dry Ice

This paper describes five experiments in which granulated dry ice was dropped into layers of cumulus cloud at temperatures below freezing. In each case precipitation of snow or ice crystals occurred, and part or all of the cloud dispersed. Displays of haloes and similar phenomena were observed.

Some Spinal Cases of Interest: (Section of Orthopædics)

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Traumatic Anterior Dislocation of the Hip

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