FEBRUARY 22, 1884. ] 
We thus have the paradoxical result that the rota- 
tion period is more than five minutes less at the equa- 
tor than in the latitude of the red spot. The effect 
of the motion of matter from one part of the planet 
to the other would be to make the actual time of ro- 
tation longer as we approach the equator. The op- 
posite effect noticed in the times of rotation of spots 
suggests the possibility that the latter may be en- 
dowed with a motion of their own; partaking, perhaps, 
of the nature of cyclones on the earth’s surface. 
RED SKIES A CENTURY AGO. 
I VENTURE to suggest that recent phenomena are a 
re-appearance of those of 1783. It will therefore be 
interesting to give a sketch of the phenomena of 
1783, in order to ascertain their similarities and differ- 
ences. 
In the spring of 1783 one of the greatest eruptions 
of Shaptar Jokul in Iceland resulted in the largest 
lava-streams ever observed, ten miles long, five miles 
wide, and a hundred feet deep. Obviously, great 
quantities of ash must also have been thrown up. 
Towards the end of May, héhenrauch (dust-haze) 
was remarked first on the western coast of Europe. 
It was so thick as to render the sun invisible on the 
horizon, and even at mid-day it was only a red indis- 
tinct disk. It was first noticed, May 29, at Copen- 
hagen, then in England, on July 6 and 7 in France, 
and rapidly spread over Europe, northern Africa, and 
eastern Asia. Neither rain, heat, nor cold dispelled 
it; and, having reached a maximum at the end of 
July, it remained visible till Sept. 26, 1783, at Copen- 
hagen, thus lasting four months. 
There are numerous instances of volcanic ash being 
carried very great distances. The dust from Cose- 
guina in Central America was carried a hundred and 
seventy miles, towards Jamaica, and was so dense 
there as to darken the sky. Hence meteorologists 
concluded that the hdhenrauch of 1783 was due to 
dust from Shaptar Jokul. 
The similarity of the 1783 phenomenon with the 
present seems to me extraordinary. The frightful 
volcanic explosion of Krakatoa in the Sunda Straits, 
which began on Aug. 26, 1883, supplies, as did Shaptar 
Jokul, the material. The splendid redness at sunrise 
and sunset was first reported from India; and it will 
be an interesting inquiry to study the spreading of 
the phenomenon, as was done in 1783. 
It was first seen in Japan at the end of August, 
but only reached Germany in November; and, from 
the dates of the various records, it seems evident that 
the ash was thrown into the upper regions of the 
atmosphere in the tropics. The extraordinary dura- 
tion corresponds with that of 1783, and is to be ex- 
plained by the fineness of the dust. 
The differences are, that in our country the obscu- 
ration of the sun is less than in 1783, which would 
accord with the greater proximity of Iceland than 
Java. 
It seems probable that rain and snow may bring 
some of the dust to the earth. I have therefore ex- 
SCIENCE: 
251 
amined the residue of the rain-gauges from the 1st 
of December, but thus far without any positive re- 
sults. Hence I infer that the dust is at present too 
high for it to be brought down: it is therefore most 
necessary that such observations be made in many 
places. 
These views have been advocated by Lockyer, who, 
through spectroscopic research, has been led to the 
same conclusion. 
Before, however, a final decision upon one or 
another hypothesis can be given, it will be necessary 
to collect observations, researches, and investigations, 
from as many points of the earth’s surface as possible, 
which will doubtless be done in meteorological jour- 
nals. G. KARSTEN. 
Kiel. 
BROWNE AND BEHNKE’S VOICE, SONG 
AND SPEECH. 
A practical guide for singers and speakers; from the 
combined view of vocal surgeon and voice-trainer. 
By Dr. Lennox Browne and Emit BEHNKE. 
New York, G. P. Putnam’s Sons, 1884. 322 p., 
illustr. 8°. 
A CAREFUL perusal of this work must estab- 
lish the conviction in the mind of the reader, 
that the authors thoroughly understand their 
subject. In reference to voice-formation, many 
hitherto obscure points are made clear, and 
_many hitherto doubtful points are settled, 
on physiological, and therefore indisputable, 
grounds. ‘Thus, the distinctions between the 
various ‘ registers’ of voice are proved to be 
due to demonstrable differences in the adjust- 
ments of the ‘ voice-box’ and the vocal liga- 
ments. <A great deal of information is com- 
municated on the subject of voice-cultivation, 
and the prevention and treatment of the 
ailments of ‘ voice-users.’ The precepts in 
regard to hygienic habits for singers and 
speakers, their diet, and their clothing, so as 
to secure unrestricted freedom for the chest 
and the abdomen, are both judicious and 
important. About one-half of the book is 
taken up with the single subject of respiration. 
The proper management of the breath is 
shown to be a matter of the highest possible 
value to singers and speakers. The conclu- 
sions arrived at, in reference to the healthful 
and efficient use of the lungs, commend them- 
selves as thoroughly sound and practical; but 
condensation in the treatment of the subject 
would have been a great improvement, as the 
same principles are again and again repeated 
under different heads. 
The use of the laryngoscope is recommended 
more than will be thought generally advisable, 
so far as practical results are concerned ; but 
the authors have handled this instrument to 
ey 
