1030 
with this view, the glacial map of Asia which 
precedes the chapter is covered with extensive 
glaciated areas over the regions which I have 
specifically visited. All of which shows the 
confusion of mind which has widely prevailed 
up to the present time concerning the glacial 
conditions of Southern Siberia and Central 
Asia, and goes to justify the editor in naming 
my article. 
4. Tam not aware that Kropotkin had any 
personal knowledge of the southeastern border 
of West Turkestan. But it is significant that 
Geikie, on his authority, speaks of ‘immense 
sheets and terraces of loess’ fringing the base 
of its mountainous border. The writer in Scr- 
ENCE assumes, as I believe unwarrantably, that 
the only indication of a former sea-level is the 
occurrence of sea shells. On the contrary, in 
the broader studies of physical geography that 
are now current, sea-levels may be determined 
in many places by terraces where shells are not 
present. - 
5. With reference to the occurrence of the 
bones of Jand animals and of terrestrial mol- 
lusks in the loess, I need only to say, that the 
great uncertainty concerning the situation of 
these remains with reference to the original 
deposit largely, if it does not entirely, breaks 
the force of the argument which is drawn from 
it. No one will deny that the wind has in 
many instances redeposited vast amounts of 
loess, nor that subsequent streams have done 
the same. But to go no farther than our own 
country, it is difficult for any one who is famil- 
iar with the situation of the loess over North- 
ern Missouri, for instance, or in the center of 
the Mississippi Valley at Vicksburg, to believe 
that it has been deposited either by the wind 
or by flowing streams of water when the land 
stood at its present level. 
In due time I hope to bring the facts in fuller 
detail before the public. But this much I may 
confidently say, that the whole problem of the 
loess has not yet been fully comprehended, 
much less has it been solved. If the renewed 
discussion elicited by my report shall contribute 
to an understanding of the subject, a great 
point will be gained. But Iam sure that the 
as yet little understood facts of Central Asia 
will contribute much toward a solution of what 
SCIENCE. 
(N.S. Vou. XIII. No. 339. 
has been one of the most perplexing of all the 
geological problems. 
G. FREDERICK WRIGHT. 
‘THE LARYNX AS AN INSTRUMENT OF MUSIC.’ 
To THE EpITOR OF ScIENCcCE: Noting in 
your issue of May 24, a communication from 
Arthur Gordon Webster quoting Professor Le 
Conte’s reference to the larnyx, comparing it 
in its function to a horn and citing a passage 
from Helmholtz containing the same compari- 
son, I am tempted to refer your readers to a 
much earlier example of the same conception. 
I quote the following from some notes of mine: 
“In 1700 Dodart (‘ Memoire sur les causes de la 
voix de l’homme,’ par M. Dodart, Memoire de 
V Academie des Sciences, 1700, p. 238) insisted 
that the trachea only furnishes the material of 
the voice, 7. e., the expired air. The glottis is 
the only organ of the voice. All the effects of 
the glottis for tones depend on the tension of 
its lips, and of its various internal structures. 
The concavity of the mouth has no part in the 
production of the voice, but it is a modifier of 
it, and still more is this true of the nose. He 
showed that Galen’s comparison to a flute 
could not be accepted if one were to go into 
details. He spoke of the vibration of the lig- 
aments, of the dilatations and contractions of 
the glottis. He asserted. that the trachea is 
elongated in high notes and shortened in low 
ones. He likened the vocal organ rather to @ 
horn or trumpet. According to him the glottis is 
the place which corresponds to the lips of the musi- 
cian; the body of the instrument extends from the 
glottis to the external orifice of the vocal canal, 
that is to say the mouth.”’ 
JONATHAN WRIGHT. 
SHORTER ARTICLES. 
PREDETERMINED ROOT-HAIR CELLS IN AZOLLA 
AND OTHER -PLANTS. 
ORDINARY root-hairs arise in acropetal suc- 
cession in the zone where the surface tissue is 
becoming fixed; that is to say, in a region at 
some distance from the root apex, where the 
cells have ceased to divide and have reached, 
or are reaching, full elongation. They come 
from any or all of the superficial cells indif- 
