The cyclic law and that of periodicity are practically identical. For what we trace as the periodicity of phenomena, can be shown to bear a direct relation to planetary cycles. Take, for instance, the periodicity of Sun-spots. The years of maximum frequency noted have led to the discovery of a period of 11 years and 40 days. Many years ago I published a statement to the effect that the rents in the luminous envelope or photosphere of the Sun would be found to coincide with the occursions of the planets Mars and Jupiter. Since then I have made further research, and I find that the mean of the two periods of these planets is 11 years and 203 days, which is in excess of the observed period of maximum solar activity by 163 days; but by taking the periods of Mars, Venus and the Earth into account, we have a period of 11 years 40½ days, which is exactly what we want. The Sun-spot period of 11·11 years is, therefore, attributable to the combined action of the planets Venus, the Earth and Mars, the mean of whose cycles yields a period so exactly in conformity with it. Probably the introduction of Jupiter and Saturn to the equation would yield a climacteric every fifth period. It is, however, of extreme interest to note that the years of the maximum Sun-spot appearance, 1871, 1882, 1904, 1916, 1927, are found to be associated with important configurations of the major planets: 1871, Saturn opposition Jupiter; 1882, Saturn conjunct Neptune; 1904, Jupiter opposition Uranus; 1916, Saturn conjunct Neptune; 1927, Jupiter conjunct Uranus. From this we might conclude that the luminous envelope of the Sun is acted upon by the planetary bodies when they are on the same solar meridian. An ingenious student of planetary influence, Prof. Corrigan, has suggested that by regarding the solar disc as a plane, and setting off the orbits of the planets from the centre, the parallels of solar latitude tangent to the orbits of Mars, Jupiter and Saturn, are those along which the greatest Sun-spot activity is shown. Thus he shows that at the latitude of 5° North and South of the Sun’s equator, spots are produced by the action of the planet Mercury on the Sun: at latitude 6° those produced by Venus’s action are seen; at 7° those due to the action of the Earth and its satellite; at 13° those frequent spots due to Mars; and at 48° those due to Saturn; while the band corresponding to the orbit of Jupiter is attended by the largest and most frequent display of Sunspots. Hence the Professor is quite in agreement with my original statement that Sun-spots are principally caused by Mars and Jupiter. This certainly upholds the original observation that Sunspots are connected with the occursions of the planets Jupiter and Mars, but it would extend the period to 11 years and 203 days. The whole subject is, however, in its infancy.