Ixxx 



General Results of the Makerstoun Observations. 



Gott. M. ' 

 1849. d. h. 

 Feb. 19 8 



10 



Marcli 18 10 



Fig^^l\ 





^il^MMK 



40™. Homogeneous auroral bank to N. with slight appearance of an arch. 



54'"-58™. Magnificent bow of aurora passing between Castor and Pollux, as in Fig. 1 ; shortly 



afterwards a series of waves 



seemed to move along the 



lower edge of the bow from 



east to west, and in a di- 

 rection opposite to the very 



violent wind then blowing 



from west ; the appearance 



of the waves is shewn in 



Fig. 2. 

 lO". The source of the waves 



was observed as in Fig. 3 ; the 



bow was seen to be at the base 



of a series of beams, which 



converged to the anti-dip ; 



the beams were but faintly 



visible, but they were observ- 

 ed to rotate about the point c, 



the centre of the corona, the 



beam a, appearing to occupy 



successive positions, till it 



arrived at the position h ; in this rotation the wave-like motion observed in Fig. 2, was produced. 



The sky was quite clear, and the wind blowing very violently. It is not a little curious that on the 



following evening, Feb. 20th, Professor Forbes observed a similar arch in almost the same position. 



He has obliged me with the following note of his observation : — 



" Edinburgh, 20th February 1849. — At 10^ 10™, p.m. [Greenvrich mean time], my attention was 

 called to a splendid auroral arch ; the brightest I ever saw. Sky clear and calm blue, diffuse light 

 in N. At 10'' 11™. Centre of band over northermost of two bright stars in Gemini (Castor and Pol- 

 lux). Motion at first a little northwards, but returned to its former position. Undulations of bright- 

 ness from E. to W. passed along the zone. Began to break up from the E. end about 10^ 18"; 

 figure became irregular, and, on the whole, to the S. of its first position. lO'' 22™. Only streaks in 

 the west remaining." 



25™. The arch passed between the stars, 38 and 40 of the Lynx, which were nearly on the meridian ; 

 at lO'' 32™, the arch passed over the two stars, X and ^ tJrsae Majoris. 



Fiff.S 



Diurnal Variation of Visible Frequency of the Aurora B or calis . — When we note from the preceding Table 

 the hours at vs'hich auroras were seen at Makerstoun, we obtain the numbers in the following Table. 



Table 70. — Number of times that the Aurora Borealis was seen at Different Hours in the Years 



1843-9, as deduced from Table 69. 



Mak. 























Nov. 



Feb. 



Aug. 





Mean 



Jan. 



Feb. 



Marcli. 



April. 



JIay. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Dec. 



March. 



Sept. 



Year. 



Time. 























Jan. 



April. 



Oct. 





5 P.M. 



1 































1 



3 



5 











5 



6 ... 



4 



2 



















1 



2 



7 



3 



14 



2 



3 



19 



7 ... 



10 



7 



4 



1 











2 



8 



7 



6 



23 



12 



10 



45 



8 ... 



9 



12 



9 



3 











5 



6 



9 



4 



22 



24 



11 



57 



9 ... 



10 



17 



12 



6 







1 



10 



12 



16 



7 



33 



35 



23 



91 



10 ... 



s 



10 



13 



12 



3 



2 



7 



8 



9 



3 



20 



35 



17 



75 



11 ... 



4 



9 



10 



7 



2 



3 



5 



3 



4 



3 



11 



26 



11 



50 



12 ... 



4 



6 



8 



7 



2 



1 



2 



1 



3 



3 



10 



21 



4 



37 



1 A.M. 



2 



3 



5 



5 



1 



3 



2 



2 



2 



2 



6 



13 



7 



i 27 



2 ... 



3 



2 



3 



2 











2 



2 







1 



4 



7 



4 



15 



3 ... 



1 







2 



2 











2 



3 







1 



2 



4 



5 



11 



4 ... 































2 







1 



1 







2 



3 



5 ... 































1 







1 



1 







1 



2 

 1 



