40 On Aerolites. 



Journal de PJnjsique, and found in volume Ix. a description of 

 some spongy stones which fell near Roa, not far from Burgos in 

 Spain, in 1438. The analogy is very striking, and I do not know 

 any oilier instance upon record which descrihes meteorolites un- 

 der a similar character. It may be considered as corroborating 

 that whicli I have detailed, and confirming its claim to a similar 

 origin : — " Mais ce qui causoit le plus d'ctonnement, e'etoit 

 leur excessive legeretc^, puisque les plus grandes ne pesoient pas 

 une demi-livre. Elles ctoient si lendres, qu'elles ressembloient plus 

 a dc I'ecume de mer condensce qu'a toute autre chose. On pou- 

 voit s'en frapper le dedans des mains sans crainte d'y causer n: 

 contusion ni douieur ni la moindre apparcnce, &c." Now this is 

 precisely the case with that in question. 



I confess that I read with some degree of astonishment Mr. 

 Brando's opinion on the origin of meteoric stones (Journal of 

 Science and the Arts, No. 10, page 294), because I believed that 

 their supposed lunar origin had been generally abandoned, and 

 that the opinion which confined them to our atmosphere had 

 ceased to be problematical. Mr. Brande observes, after stating 

 the questions of their being " earthy matter fused by lightning?" 

 or " the offspring of a terrestrial volcano?" and adverting to 

 the inexplicable projectile force that would here be wanted, that 

 " this is merely explaining what is puzzling by assuming what 

 is impossible," and that, in this conjecture, the advocates of 

 such an opinion " have assumed one impossibility to account 

 for what they conceive to be another." The Professor then con- 

 tinues : " The notion that these bodies come from the moon, 

 though it has been laughed at as lunacy, is, when impartially 

 considered, neither absurd nor impossible; — It is quite true," 

 says he, " that the quiet way in which they visit us is against 

 such an origin ; it seems, however, that any power which would 

 move a body 6000/ee^ in a second, that is, about three times 

 the velocity of a cannon-ball, would throw it from the sphere of 

 the moon's attraction into that of our earth. The cause of this 

 projective force may be a volcano; and if thus impelled, the body 

 would reach us in about two days, and enter our atmosphere with 

 a velocity of about 2.5,OGO/ee/'i// a second." With every respect 

 for Professor Brande's opinion, and highly as I may value it, it 

 is impossible for me to receive the present in any other than a 

 very doubtful form.— Mr. B. denies to any volcano on the ter- 

 restrial surface a projectile power of extent sufficient to propel vol- 

 canic dust to the required elevation; and yet unhesitatingly gives 

 to lunar volcanoes one not merely of enormous, but of almost in- 

 conceivable impetus. Now, to say nothing of the " quiet way 

 in which they visit us," the very existence of lunar volcanoes, to 

 state the least of it, is exceedingly questionable. Sir W. Her- 



schel 



