2.4.Sudden Increases

Since reliable readings of cosmic ray intensity commenced in 1936 there have been four major increases in activity:

• 1942, January 31.

• 1942, February 7.

• 1946, July 25.

• 1949, November 19.

and in each case these bursts were proceeded by a radio fade out caused by a violent chromospheric eruption near an active sunspot. In 1946 and 1949 the newly developed techniques of measuring radio noise showed a tenfold increase from the sun.