When the Observatory on the summit of Ben Nevis was opened in 1883, arrangements were made with Mr Colin Livingston, of the Public School, Fort-William, whereby observations were made five times a day at the Schoolhouse for comparison with those on Ben Nevis. These observations, from December 1883 to December 1887, were published in vol. xxxiv. of the Transactions R.S.E., along with the Ben Nevis records; and three years more, up to December 1890, are given in this volume (see Introduction, p. 7). The Fort-William Observatory was opened in August 1890, but Mr Livingston kindly continued his observations till the end of 1891, so as to allow of a comparison between these two stations, which was the more desirable as Mr Livingston's observations had been used for the original determinations of the differences of pressure and temperature between Ben Nevis and sea-level, and any discrepancy between the observations made at the Schoolhouse and at the Observatory would necessitate a readjustment of these constants.