464 Intelligence and Miscellaneous Articles. 
CLASSIFICATION OF METEORITES. 
Professor Tschermak, who has made many important contri- 
butions to the study of meteorites, has been led by the results of 
recent microscopic study to propose some changes in the system of 
classification given by Rose in 1864. The meteorites are classified 
after the principles of lithology according to the kind and relative 
amounts of their mineralogical constituents. The classification as 
proposed by Tschermak, with some typical examples under each 
head, is as follows :— 
I. Meteorites consisting essentially of iron : Meteoric iron. 
II. Meteorites having an iron ground-mass with enclosed sili- 
cates. («) Pallasite : iron and olivine the chief constituents (Pallas- 
iron, Atacama, Bitburg) ; (b) Mesosiderite : iron with olivine and 
bronzite (Hainholz, Estherville) ; (c) Siderophyr : iron and bronzite 
(Kittersgriin, Breitenbach, Steinbach) ; Grahamite : iron with pla- 
gioclase, olivine, bronzite (Serra da Chaco). 
III. Meteorites consisting chiefly of olivine and bronzite with 
iron as a subordinate constituent ; the texture mostly chondritic. 
Chondrite (Aigle, Knyahinya, New Concord, Pultusk). 
IV. Meteorites consisting essentially of olivine, bronzite, 
pyroxene, (a) Chassignite : olivine (Chassigny) ; (b) Amphoterite : 
olivine and bronzite (Manbhoom) ; (c) Diogenite : bronzite or 
hypersthene (Ibbenbiihren, Shalka); (d) Chladnite, enstatite 
(Bishopville) ; (e) Bustite : diopside and enstatite (Busti). 
V. Meteorites consisting essentially of augite, bronzite, lime 
felspar; with a shining crust, (a) Howardite: augite, bronzite, 
plagioclase (Frankfort, Loutolaks) ; (b) Ealcrite : augite, anorthite 
or maskelynite (Juvinas, Jonzac, Stannern, Peterborough). — Silli- 
man's American Journal, ~Nov. 1883 (Ber.Alc. Wien, July 7, 1883). 
PROFESSOR FERREL S THEORY OF ATMOSPHERIC CURRENTS. 
To the Editors of the Philosophical Magazine and Journal. 
Gentlemen, 
Understanding that you consider that this question has been 
sufficiently discussed in your pages, I nevertheless hope you will 
allow me to set myself right with Prof. Everett. 
First, by acknowledging a blunder which he has pointed out. 
A mass moving in a fixed great circle over the earth's surface does 
gain and lose, not only relative (as I said), but also absolute 
velocity parallel to the equator, because it changes its direction 
relative to that plane. 
Secondly, by stating that this is not the doctrine which I still 
understand Prof. Ferrel to maintain, and which I still dispute. 
Thirdly, by pointing out that this, after all, is not "the main point 
of my criticism." That main point is the utter baselessness of the 
mathematical theory propounded in the paper of 1860. 
I remain. 
Kitlands, Dorking, Your obedient servant, 
Oct. 27th, 1883. D. D. Heath. 
