Decembku 7, 188:5.] 



SCIENCE. 



729 



adults of transition forms from Xantiloidea to 

 Ammonoidea, and set down his convictions 

 that the Ammonoidea must have been derived 

 from Nautihis through these transition forms, 

 the gradations being Nautilini, Goniatitcs. 

 Ammonites. Barrande then pictures this same 

 naturalist as attempting to verify his appar- 

 entlj- well-founded conclusions by opening a 

 species of Goniatite with the anticipation of 

 discovering within, at the apex, or young shell, 

 an identical form and structure to that which 

 he had been accustomed to find in the Nauti- 

 loidea, and his consequent confusion, and the 

 overthrow of his theory, upon the exposure of 

 a different form. Barrande's argument deals 

 fairly with every point ; and his facts are crush- 

 ing refutations of the usual direct, simple 

 modes pursued by embrvologists in handling 

 the question of the evolution of types. Bar- 

 rande's work had no orators or lecturers to 

 translate it ; and the hypothesis of the embry- 

 ologists, and even evolution itself, escaped an 

 attack, wliich, if supported by powerful in- 

 fluences, might have shaken the popular fiiith 

 in the new school of thought. 



Hyatt lias denied that there were such great 

 and essential diflerences between the eml)ryos 

 of the Nautiloidea and those of the Ammonoi- 

 dea ; and they certainly seem to have been 

 more alike than was supposed by M. Barrande. 

 The fact, however, remains, that Barrande saw 

 clearly that the embryos of these two nearl3' 

 allied groups, which are united by most authors 

 into one order, were, even in the Silurian, more 

 easilj' separable from each other than some of 

 the adult forms. When we can add to this, his 

 discovery and thorough demonstration of the 

 distinctness of tlie diflerent types of fossils in 

 the Silurian, and tlieir sudden mode of appear- 

 ance, we see clearly that he succeeded in doing 

 the work which has thrown the greatest light 

 upon the most obscure and interesting periods 

 of the world's history, and wiiich has furnished 

 a temperate and healthy opposition to the 

 tiieor3- of evolution. His faults of logic were 

 unavoidable, with his mathematical and C'uvic- 

 rian education, and strong feelings of loyalty 

 to ids masters in science ; but these arc only 



slight scratches upon tiie face of the vast monu- 

 ment erected by his hil)ors, his discoveries, his 

 eightj'-three years of unblemished moral and 

 faithful life, and his personal s.acrifices for the 

 advancement of science and the truth. 



WHIRLWINDS, CYCLONES, AND TOR- 

 NADOES.^— y. 



Cyclonic circulation has thus far been de- 

 scribed as if it were effected in radial lines in 

 to and out from the centre ; but here, as in the 

 whirlwind, perfect radial motion is impossible. 

 A horizontal rotary motion would soon be es- 

 tablished near the centre by the inequality of 

 the inblowing winds. It is found, however, 

 that all storms yet studied turn from right to 

 left in the northern hemisphere, and fVoni left to 

 right in the southern (fig. 0). Such constancy 

 points to something 

 more regular than the 

 accidental strength of 

 the winds, — to some 

 cause that shall always 

 ttnn the indraughts to 

 tlie right of the centre 

 as they run in towards 

 it in tjic northern hem- 

 isphere, and to the left 

 in the southern hemi- 

 sphere ; and this cause 

 is found in the rota- 

 "tion of the earth on 

 its axis. 



There is a force aris- 

 ing from the earth's 

 rotation that tends to 

 deflect all motions in 

 the northern hemi- 

 sphere to the right, 

 and in the southern to 



the left ; and this deficcting force varies with 

 the latitude, iieing notiiing at the equator, and 

 greatest at the poles. It may be found that 

 this statement differs from that generally 

 made : name!}", that moving bodies are de- 

 flected only when moving north or south, and 

 not at all when moving east or west :' for it is 

 thus th.at Iladley (17:).')) and Dove (183a) ex- 

 plained the obli(|ue motion of trade-winds, and 

 that Herschel and. others explained the rotation 

 of storms. But this is both incorrect and in- 

 complete ; for a body moving (?astward is 

 deflected as well as when moving northward, 

 and the actual deflective tbrce is greater than 

 that accounted for in Iladley's explanation. 



> continiu.l from No. 43. 



