He was also one of the first to carry out meteorological studies in Peru, traveling extensively in desolate areas at very high altitude.

[5] He made extensive studies of variable stars in globular clusters in the southern skies.

He also performed a light-curve analysis measuring the rotation period of the near-Earth asteroid 433 Eros during its 1903 opposition.

[5] Bailey was acting director of Harvard College Observatory from 1919 to 1921 after the death of Edward Charles Pickering and prior to the appointment of Harlow Shapley.

[7] Irving died on June 5, 1931, aged 76, in Hanover, New Hampshire, from an illness caused by heart disease.