380 Mr. W. R. Birt on the Storm-paths 



the half of an ellipse of greater or less eccentricity ; the apices 

 are confined to the thirtieth parallel of latitude, and are more 

 acuminated as they recede from the fiftieth degree of longi- 

 tude west of Greenwich. The remaining eight depart consi- 

 derably from this type : four appear in some measure to ap- 

 proximate to it, but most probably with very acuminated 

 apices. A most remarkable one, of a parabolic form, with 

 its apex on the twenty-sixth parallel, was observed in October 

 1837 (XV.). In- October 184-2, the north-western portion of 

 an elliptic path with the apex still lower was traced (XIII.). 

 The storm pursuing this path is particularly discussed in the 

 continuation of Mr. Redfield's paper, and its identity with the 

 northers of the Mexican coast insisted on. Mr. Redfield also 

 speaks of other storms that had exhibited the character of 

 northers in the Gulf of Mexico, and afterwards presented all 

 the features of Atlantic storms. Speaking of a storm that oc- 

 curred in October 1837, he says, " This norther of the Mexi- 

 can coast had become in due course of progression an At- 

 lantic storm" (see American Journal of Science, second series, 

 No. 2, March 1846, p. 166). In October 1844, a storm 

 passed nearly in a direct line from the Gulf of Honduras to 

 Newfoundland (XIV.); and to the gale which is first dis- 

 cussed in the articles before us (XII.), a nearly direct west- 

 erly course has been assigned from all the observations that 

 have come to hand. 



It is not my intention in the present communication to enter 

 into any examination of the particular gales above enumerated, 

 or to attempt to substantiate or refute either the one or the other 

 of the rival theories which have been offered as an explana- 

 tion of the phenomena. Those of your readers who are ac- 

 quainted with Col. Reid's work, are aware that he has most 

 ably discussed the rotatory theory, and for the centripetal 

 theory, I beg to refer to various papers in the American Journal 

 of Science. I apprehend that the labours of Redfield, Loomis, 

 and Espy in the United States, Col. Reid in England, and 

 Piddington and Thom in India, have brought the inquiry to 

 that point at which it becomes essential to connect it with 

 some kindred branch of science, in order to see our way clear 

 in resolving the interesting problems that suggest themselves, 

 to strike out a path for working energetically in surmounting 

 the obstacles that still retard our progress in becoming ac- 

 quainted with the dynamical system of our atmosphere, and 

 in successfully removing the desiderata as they arise. 



Among the desiderata of these phaenomena, and by far the 

 most important, will be found their origin and final disappear- 

 ance. Sir John Herschel has suggested, in his Report on 



