Warren de la Rue, Balfour Stewart and Benjamin Loewy: Planetary Influence on Solar Activity

I came across this old paper, which may turn out to be very important. Balfour Stewart was head of solar research at Kew Observatory in the latter part of the C19th. This study demonstrates an effect of the planets on the size of sunspots, which may be connected with gravitationl, tidal and electro-magnetic forces interactions operating in the heliosphere.