422 



SCIENTIFIC EECORD FOR 1882. 



witnessed, were enconutered by several well-appointed steamers out in 

 the middle of the North Sea during this storm, thus confirming the ob- 

 servations of the Eymouth fishermen. These facts seem to point to 

 one or j)erhaj>s two tornadoes with slanting* columns, the terrific force of 

 the gyrations of whose lower extremities played no inconspicuous part 

 in the devastation wrought during the continuance of this memorable 

 storm. (Nature, XXY, 1^.157.) 



J. A. B. Oliver, of Glasgow, in a note on the frequency of hail-storms 

 in Great Britain, gives the following data: 



Months. 



Farmer's 

 Insurance 

 Institute, 

 annual av- 

 erage. 



Daltou's 

 total in five 

 years of ob- 

 servation. 



Giddy 's total 

 in twenty- 

 one years at 

 Penzance. 



Thomson's 



relative pi o- 



portions. 



Winter 



January ... 



February .. 

 Spriuu 



March 



Apiil 



May 



Summer 



June 



July 



August 



Autumn 



Se])tember. 



October 



November. 



December.. 



45. 5 to 54. 5 

 20. 5 to 70. 



22. to 78. 



3. to 97. 



From a comparison of these tables we see that Daltou, Giddy, and 

 Thomson agree in making winter the season of maximum hail-fall, while 

 the insurance statistics i^oint to the opposite con(;lusion, the hail-storms 

 in June and July being much in excess of those in the other months of 

 the year. Oliver strongly suspects that Dalton, and other observers 

 who have arrived at similar results, included in their enumeration of 

 hail-falls, what we may call, in absence of a better name, winter hail. It 

 is very unfortunate that the word "hail" has, in our language, been 

 used to denote two entirely different phenomena, the French grele, 

 or hail proper, and gresil, or that small, round, powdery snow which 

 often falls towards the end of a snow-storm and in the early part of a 

 very frosty night. Gresil has nothing in common with grele. The one 

 falls exclusively in winter, and the other, perhaps, as exclusively in 

 summer. {Nature^ June 30, 1881, xxiv, p. 190.) 



X. — a Atmospheric electeicty ; b Terrestrial magnetism -, c 

 Ground currents ; d Auroras. 



In the first lecture at the South Kensington Museum on solar physics 

 by Professor Stokes, October, 1881, he suggests some new views in re- 

 gard to atmospheric electricity. He says : 



"Where shall we get the electromotive force sufficient to send a dis- 

 charge through 50, GO, or SO miles of atmosphere, such as occurs in the case 

 of the auroral streamers ? Measurements made upon the Atlantic cable 



