Cyclones. 329 



Fig. 3. Limulus Walchii, Desmar., -^th the natural size; 

 from the Lithographic stone of Solenhofen, Bavaria. 



Fig. 4. Bellinurus (Limulus) rotundatus, Prestw., -j-rds 

 the natural size ; Coal-measures, Coalbrook-dale, occurring in 

 pebbles of clay-ironstone. 



Fig. 5. Bellinurus regime, Baily; Coal-measures, Ireland.* 



Fig. 6. Bellinurus (Limulus) trilobitoides, Konig. ; Carboni- 

 ferous Limestone, Ireland. 



Fig 7. Hemiaspis limuloides, H. W. (the natural size) ; 

 Lower Ludlow rock, Leintvvardine, Shropshire. 



Fig. 8. Harpes ungula, Sternberg (the natural size) ; Upper 

 Silurian, Bohemia. 



Fig. 9. Dithyrocaris Scouleri, M.cCoy ; Carboniferous Lime- 

 stone, Ireland. 



Fig. 10. Apus cancriformis, Schteffer ; recent ; living in fresh- 

 water lakes, Bohemia. 



Fig. 10, a. b. c. Different degrees of development of the 

 larval Apus (after M. Zaddach) . 



Fig. 10, d. Adult female, natural size (dorsal aspect). 



CYCLONES. 



BY A. S. HERSCHEL, B.A. 



The revolution of the earth about the sun, its globular figure, 

 and its daily rotation on its axis, occasions its variety of 

 climates, its day and night, and its regular succession of the 

 seasons. The trade winds, anti-trade winds, and monsoons are 

 at the same time set in motion, as well as land and sea breezes, 

 and keep up a constant agitation in the atmosphere ; by which 

 the local moisture, temperature, and density of the atmosphere 

 are disturbed and rendered unstable. Its strata become the 

 scene of shifting winds, and are often dislocated by tempests 

 of the most violent kind. The most violent of these tempests 

 are conformable to a certain law, called — perhaps in default of 

 a better term — " the law of storms." Readers of the Intel- 

 lectual Observer who regard it as a barbarism to couple the 

 idea of law and harmony with anything so lawless as a storm, 

 may substitute for this expression, wherever it occurs, without 

 selection, the " theory of cyclones.-" 



The damage occasioned by hurricanes, like the destruction 

 caused by earthquakes or volcanoes, is incalculably great. To 



* See explanation of sheet No. 137, p. 12 — 14, " Geological Surrey of 

 Ireland, 1859." 



