Nov. 1907. ] THE PRESIDENTIAL ADDRESS. 359 
during the long period of forty-seven years. He possessed 
a remarkable memory, a marvellous faculty for handling 
great masses of figures, and a penetrating insight into the 
meaning and significance of statistical returns collected 
from widely separated stations. These qualities enabled 
him to be largely instrumental in securing the general 
acceptance of Buys Ballot’s principle of the relation of 
wind to air pressure. Variations in atmospheric pressure 
at given points, and the fact that the direction of the 
wind was connected with the relative distribution of 
pressure, were well known before his time, and had been 
systematised to the extent of definitely marked lines of 
equal pressure, or “isobars,” for several countries. But it 
required the patience, genius, and rare statistical skill of 
Alexander Buchan to co-ordinate the enormous masses of 
statistics gathered together from all parts of the world. 
This he did in his paper on “The Mean Pressure of the 
Atmosphere and the Prevailing Winds over the Globe,” 
published in the “Transactions of the Royal Society of 
Edinburgh” in 1869. To us who are so familiar with the 
daily results of meteorological observations it is difficult 
to believe that Alexander Buchan was the first to trace 
the course of a “depression” across the Atlantic. This 
gigantic and epoch-making achievement embodied in the 
previous paper raised him at once to a position of acknow- 
ledged pre-eminence as a meteorologist in Europe and 
America, and he retained this high reputation to the last. 
It was enhanced by his “Handy Book of Meteorology,” 
published in 1867, and his “Introductory Text-book of 
Meteorology,” in 1871. He was fittingly chosen to examine 
the meteorological observations of the “ Challenger” Expedi- 
tion, and the results of many years’ labour thereon were 
embodied in the two monographs, “ Atmospheric Circulation,” 
published in 1889, and “ Oceanic Circulation,” in 1895. He 
was profoundly interested in the high-level meteorological 
station on Ben Nevis erected by the Royal Societies of 
London and Edinburgh, and was keenly disappointed when 
it had to be closed for want of adequate financial support. 
The study, co-ordination, and elucidation of the accumulated 
observations at this station occupied most of his time in 
later years, and had not been completed at the time of his 
