An introduction to the study of meteorites; with a list of the meteorites represented in the collection
British Museum. Dept. of Mineralogy
Paperback
(RareBooksClub.com, May 14, 2012)
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1888 Excerpt: ...stones, it will be seen that almost all of them and their '.. matrix, appear to be made up chiefly of irregular angular fragments, and that some of them bear a close resemblance to volcanic tuffs. In the large group of chondritic aerolites, chondruies or spherules, some of which can only be seen under the microscope while others reach the size of a cherry, are embedded in a matrix, apparently made up of minute splinters such as might result from the fracture of the chondruies themselves. In fact, until recently, it was Other structural characters. thought by some, that the chondrites owe their form, not to crystallisation, but to friction, and that the matrix-was actually produced by the wearing down of the chondrules through collision with each other either as oscillating com-ponents of a comet or during repeated ejection from a volcanic vent of some small celestial body. Chondrules have been observed, however, presenting forms and crystal-line surfaces incompatible with such a mode of formation, and others have been described which exhibit features resulting from mutual interference during their growth. The crystallisation of the chondrules is independent of their form, and must have started, not at the centre, but at various places on their surfaces; Sorby argues that some at least of the chondrules must once have fallen as drops of fiery rain, and have assumed their shape in an atmosphere heated to nearly their own temperature. The chondritic structure is different from anything which has been ob-served in terrestrial rocks, and the chondrules are distinct in character from those observed in perlite and obsidian. After a minute study of the classical collection at Vienna, BrezinaJ lends his weighty support to the theory that the structural features of m...