THE METEOKOLOGY OF BEN NEVIS. 



By ALEXANDER BUCHAN, LL.D., 



SECRETARY OF THE SCOTTISH METEOROLOGICAL SOCIETY. 



The attention of meteorologists was almost exclusively directed, till quite 

 recently, to the collecting of the observational data necessary for determining the 

 diurnal variation and the geographical distribution of the temperature, pressure, 

 moisture, and movements of the atmosphere and the rainfall. In conducting 

 these inquiries, the importance of the study of the changes of weather came 

 gradually to be recognised, and an additional impetus was given to the prosecu- 

 tion of this branch of meteorology when it was seen that the subject had inti- 

 mate relations to the practical question of weather forecasts, including storm 

 warnings. Weather maps, showing the state of the weather over a consider- 

 able portion of the earth's surface, began to be constructed, and rapid pro- 

 gress was at once made in our knowledge of the more striking changes of 

 weather as these occur from clay to day. 



One of the largest and most important practical problems of meteorology is 

 to ascertain the course which storms follow, and the causes by which that 

 course is determined, so that we may forecast from the meteorological pheno- 

 mena observed, not only the certain approach of a storm, but the particular 

 course that storm will take. The method of conducting this large inquiry in 

 the most effective manner was devised by the genius of Leverrier, and began to 

 be carried out by him in 1858 by the daily publication of the Bulletin Interna- 

 tional, to which a synchronous weather map was added in September 1863. 

 This map showed graphically for the morning of the day of publication the 

 atmospheric pressure and the direction and force of the wind, together with 

 tables of temperature, rainfall, cloud, and sea disturbance from a large number 

 of places in all parts of Europe. It is from such weather maps that forecasts 

 of storms are framed and suitable warnings issued, and a body of information 

 is being collected which is gradually leading to a juster knowledge of those 

 great atmospheric movements and other changes which form the groundwork 

 of the science. 



These weather maps practically take note only of the meteorological con- 

 ditions and changes which are observed at one height, viz., the level of the sea. 

 vol. xxxiv. c 



