0^ THE THEORY OF POINT-GROUPS. 



93 



sentation of all geometrical loci of this degree which pass through the 

 intersections of the lines or surfaces represented by the original equations. 

 It is evident, however, from the examples, that Lame is really concerned 

 with actually obtaining the necessary conditions in order that three or 

 four given equations may hold simultaneously, and that the singly infinite 

 (and linear) nature of the system in the one case and the doubly infinite 

 (and linear) nature of the system in the other are not of primary import- 

 ance to him. 



Meteorological Observations on Ben Nevis. — Report of the Committee, 

 consisting of Lord M'Laren, Professor A. Crum Brown (Secretary), 

 Sir John Murray, Professor Copeland, and Dr. Alexander 

 BUCHAN. (Draivn up by Dr. Buchan.) 



The Committee were appointed for the purpose of co-operating with the 

 Scottish Meteorological Society in making meteorological observations at 

 the two Ben Nevis Observatories. 



The hourly eye-observations made at the top of the mountain by night 

 as well as by day have been regularly made by Mr. Angus Rankin, the 

 superintendent, and staff of assistants. As the observatory at Fort 

 William is one of the observatories of the Meteorological Council, the 

 observations there are taken from the photographic curves. 



The health of the observers has been good during the year. The 

 directors desire to express their very cordial thanks to Messrs. A. Watt, 

 M.A., T. Affleck, R. Aitken, William S. Bruce, and G. Philip for the 

 invaluable services rendered by them as volunteer observers at certain 

 seasons of the year, particularly during the summer months, thus securing 

 to the members of the staff of both observatories the rest they needed from 

 their arduous work ; and to Messrs. Wedderburn and Aiken for the 

 valuable observations they have made this summer at the half-way station 

 on the Ben. 



The principal results of the observations made at the two observatories 

 during 1900 are detailed in Table I. 



Table I. 



