1884. ] Mineralogy. 183 
out western Transylvania suddenly burst, and three minutes after 
its disappearance a series of detonations was heard. The path of 
the meteor was for a long time marked by a grayish-white cloud. 
Some 3000 stones fell, the largest of them weighing over 38 kil- 
ogrammes. Analysis showed that they were stone meteorites 
containing a percentage of 9.88 nickel-iron, 6.63 magnetic pyrites 
and 83.49 silicates, 
Tu Fetpspars.—Speaking of the importance of a correct de- 
termination of the feldspars, J. Szabo! remarks “that it is the 
unanimous conviction with petrographers that every kind of a 
rock mass can be best determined by the mineral association 
found in it, and of all mineral it is the kind of feldspar which is 
most important. There was a time when we had been contented 
to say feldspar generally; then came a time when we said ortho- 
clase and plagioclase; but now we know that this is not enough ; 
we must discern among the plagioclases according to their basic- 
ity, at least an oligoclase-andesite, a labradorite, and a bytainite- 
anorthite.” He states that in the case of an eruption, the most 
acid feldspars are the first product of eruption and the most basic 
the last, and that in many cases “the determination of the feldspar 
is the only possible way of saying something of the lithological 
and chronological character of the rock in question.” 
In order to determine the feldspar in the quickest way, he rec- 
ommends flame experiments, and describes his method of work. 
It is based upon the coloration of the flame of a Bunsen burner 
Parts of the flame. He distinguishes seven degrees of fusibility 
from Bronzite (1) to Stibrite (7), in each case holding the grain in 
the flame for one minute, and noting the degree of fusion. “ So- 
rises is the element in the silicates which makes them easily 
usible, the magnesium and aluminum render them less fusible or 
altogether infusible,” 
: to the coloration of the flame, he uses a solution of indigo 
sulphuric acid, through which to observe the coloration by: 
Potash, and discovers five degrees in the yellow flame of sodium, 
eee three degrees for the red flame of potash, the intensity of 
“0 ration depending upon the percentage of the alkali. 
woe ne these observations with an examination of the 
er of the fused globule, it is claimed that all the principal feld- 
fal that, be racognized. It is doubtful, however, whether a care- 
Sure ree unless made confident by long practice, would be 
on his determination by this method. The almost universal 
“trenee of a mixture of two or more feldspars renders any 
7 1 
_ Proc, Amer. Assoc, Adv. Sci., XXXI., 270, 1882. 
