The investigation thus entered upon, together with the zone observations just mentioned, and the continuation by ampler and in some particulars radically different methods of investigations in spectroscopy and photography, have given the institution a wide renown. But hardly less conspicuous are certain other achievements in the long list which makes the complete record. Without attempting to give any of these rank, still less to repeat the list, a few may here be mentioned upon the ground of their presumed popular interest. In 1878 the utility of the time signal service was increased by causing a time ball to be dropped every day at exact noon from a conspicuous point in Boston within view of the shipping of the harbor. The time was that of the meridian of the State House in Boston. When the standard or 75th meridian time went into general use the practice was conformed thereto. Indeed, the terms of the proposition might be reversed so as to indicate that, in the final determination, the responsibility was put upon the observatory to lead off in the matter. There had been some discussion in the public prints and elsewhere of the advisability of adopting a common meridian time for large areas. In the report of the observatory for 1878 the theoretical presentation of the case which had been made by those advocating the change was sanctioned, and the new time was recommended as sure to be of public convenience if generally accepted. General consent was somewhat slow in its manifestation, but eventually the managers of all the principal railroads of New England agreed to adopt the plan if the time-signalling system of the observatory should be made to correspond in respect to clock connections, time ball, etc. This was instantly agreed to, and with due prior public notice the new time went into use Nov. 18, 1883, and the Boston noon ball was first dropped on that day at exactly five hours later than the noon of Greenwich. [Illustration: HARVARD COLLEGE OBSERVATORY.] [Illustration: HARVARD STATION IN CALIFORNIA.] In 1880 the full routine of meteorological observation was abandoned, as several institutions were doing like work. The record of the observatory in meteorology, which had continuously been kept up for 40 years, was reduced to proper form for printing, and was published in 1889. Certain observations of this kind have, however, been continued in the record to the present date. In 1888 a plan of co-operation was agreed upon with the N. E. Meteorological Society and Mr. A. L. Rotch of the Blue Hill, Mass., Observatory, by which their results, which are of a comprehensive character, have since been published in the annals of the Harvard Observatory.