H. HENSOLDT ON CAVITIES IN METEORITES. 189 



prove that they are in the wrong and myself in the right would be 

 futile with the scientific public at large, at least in this country, 

 where general information is not so diffused, that is, where the 

 knowledge of a plurality of scientific subjects is more rarely met 

 with in the same individual, and where the solution of problems 

 not entirely self-evident is habitually referred to known specialists, 

 whose opinion is thenceforward quoted as "law " by the majority. 

 While I would invite every observer who may feel an interest in 

 this subject to think and test for himself, unbiassed by any criticism 

 not resulting from his own research, I do not wish to detract from 

 the merit of opinions already expressed by authorities more or less 

 eminent. But I may point out that at least, those which have 

 come to my knowledge are not characterised by great unanimity. 

 They agree, it is true, in their denial of the meteoric origin of the 

 specimen from Braunfels, but here the comparison ceases, although 

 I should imagine that if they are unanimous in declaring what it is 

 7iot, they should be equally unanimous in establishing what it is. 

 Between the opinions of Mr. Fletcher, of the British Museum, the 

 custodian of the Mineral ogical Cabinet of Vienna, and Dr. Sorby there 

 is a marked discrepancy, for one considers the opaque substance in 

 the specimen to be Hematite, another metallic iron, and the entire 

 mass the produce of a melting furnace, and the third (if I am 

 rightly informed) a kind of ferruginous quartz. I am also of 

 opinion that it is entirely fallacious to establish the possibility of the 

 occurrence of the one or the other substance in a meteorite by 

 comparison with what is known of the composition of other 

 meteorites. If we regard the countless myriads of meteorites 

 which are known to traverse space, and which most probably pre- 

 sent a vaster diversity of mineral combination in the aggregate than 

 exists on this globe ; and if on the other hand we consider the 

 isolated few which have happened to fall on the earth, it appears in 

 my eyes an absurdity if, from the accidental composition of the latter, 

 we were to determine what is possible and what is not possible in 

 a meteorite. 



Respecting the fluid cavities, I may mention that shortly after 

 the publication of my paper, M. A. de Souza Guimaraens, F.R.M.S., 

 who happened to possess a number of meteoric sections, some by 

 well known mounters, such as Moller, but which he previously had 

 never thought of carefully examining with high powers, found fluid 

 cavities with bubbles in continual motion in nearly every one of 



