Observatory Report.

The annual report of the Astronomical Observatory, recently issued by Professor Pickering, reviews in detail the work of the department for the past year. It states that three important astronomical events have occurred since the last report: the opposition of the planet Eros, which brought the planet nearer to the earth than it will be again for many years; the appearance of the New Star in Perseus, the brightest object of its class which has been seen for three hundred years; and the total eclipse of the sun in Sumatra.

Among the more important results of the investigations of the past year is the discovery of two new variables, three stars having peculiar spectra and the presence of hydrogen lines in the spectrum of V. Andromeda. The discovery of the variability of light of Eros has added greatly to the value of the early Photographs of that body. Photographs of the spectrum of lightning were obtained last summer for the first time. It is expected that the discovery will open a new field for spectroscopic work.

In addition to the regular routine at the Blue Hill station semi-daily observations have been made of audibility and of the refraction of Mt. Wachusetts. The possibility of kite flying in calm weather from moving steamers was demonstrated. This discovery will open an extensive field for research, especially in the tropics.