PROCEEDINGS 
OF THE 
NATIONAL ACADEMY OF SCIENCES 
Volume 6 AUGUST 15, 1920 Number 8 
ON CHONDRULES AND CHONDRITIC STRUCTURE IN 
METEORITES^ 
By Gkorgk p. Mkrrii.Iv 
U. S. Nationai. Museum, Washington, D. C. 
Communicated by J. M. Clarke, May 12, 1920 
The term "chondrit," from the Greek xo^^^por, a grain, was first used, 
so far as I am aware, by Gustav Rose^ to designate a class of stony meteor- 
ites characterized by the occurrence of small granules or ''kugeln.'' "Sie 
ist durch kleine Kugeln ausgezeichnet die aus einem noch nicht bestimmten 
Magnesia- Silicate bestehen, und in einem fein kornigen Gemenge einge- 
mengt sind," etc. The word, with the addition of the terminal e, as 
Chondrite, has been very generally adopted, with its original meaning, 
by English and American writers. Unfortunately, as it would seem, a 
further modification of the word as ckondros, chondrule, chondrus, or 
chondrum has been introduced, at first apparently synonymous in meaning 
with kugel as used by Rose though it is to be noted that he did not define 
the word quite as clearly as might be desired. He wrote: * * in 
Bruche erscheinen sie theils unehen, tkeils fasrig, im letzern Fall jedoch 
stets nur sehr feinfaserig, indessen doch immer bestimmt erkennbar 
fasrig, besonders unter der Lupe * * nie radial, sondern immer excen- 
trisch fasrig." No further reference is made to those of "uneben Bruche" 
and one is left only to surmise that they may have been of a granular or 
porphyritic rather than fibrous structure. The fact that Rose's work was 
written before the day of thin sections doubtless accounts for the unde- 
termined character of the magnesian silicate. 
Tschermak in his Mikroskopische Besckaffenkeit (1885) was little more 
explicit in his use of terms than was Rose. He wrote: "Kugelchen und 
uherkaupt rundlicke Kdrper, welche bald aus einem einzigen krystallin- 
dividuum, bald aus mehreren bestehen, ofters auch aus verschiedenen 
Gemengtheilen zusammengestzt sind, bilden das Gestein fast allein (Borkut) 
Oder sie lagern unverletzt, ofters auch zersplittert in einer lockeren bis 
festen Tuff masse." Elsewhere he includes all the rounded forms under 
449 
