He had introduced his method of analysis of two star-drifts, and his prevailing interest in statistical stellar astronomy was concentrated on the systematic motions and distribution of the stars throughout his Greenwich years.
Ipinakilala niya ang kanyang paraan ng pagtatasa ng dalawang bituin-drifts, at ang kanyang mga nangingibabaw na interes sa statistical bituin astronomy, ay puro sa sistema motions at pamamahagi ng mga artista sa kabuuan ng kanyang Greenwich taon.