From the commencement of the meteorological researches on Ben Nevis, a double set of observations have been carried on—one set on the top of the Ben, and the other at a station at Fort William near the level of the sea. It is not so much from the observations made on the top considered by themselves, as to their relations to those made at the base, that we may hope to arrive at a better knowledge of the atmosphere, and particularly at a better understanding of the principles of weather forecasting. Accordingly, both stations were from the first fitted up with the best instruments.