Dec. 16, 1869] 
NATURE 
eS 
that no great damage was done to buildings is ascribed to the 
movement being chiefly vertical, The horizontal direction is 
stated by an observer to be from south-west to north-east, and 
by another from north-east to south-west. 
SCHOPENAUER’S treatise on the ‘‘ Philosophy of vision and 
colours,” which originally appeared upwards of fifty years ago, 
and which has hitherto been treated with unmerited neglect by 
the great writers on physiological optics, has just reached a third 
edition. An interleaved and annotated copy of the second edition 
prepared by the author himself in 1854 was found amongst his 
papers, and has formed the basis for the present ‘‘ improved 
and augmented” reissue, which appears under the editorship 
of Julius Frauenstadt. 
WE desire to call special attention to the singularly interest- 
ing address of the new Rector of the University of Vienna, 
Carl von Littrow, on a subject which does not at first sight 
appear to be of a very interesting character, viz., the backward- 
ness of the ancients in the sciences. This backwardness he 
ascribes, firstly, to an actual want of the power of accurate ob- 
servation ; and, secondly, to a restless spirit of speculation. The 
illustrations of these positions are drawn from astronomy, the 
science to which in early times the greatest care was devoted. 
Of the instances adduced to show that the ancients, notwith- 
standing their fine feeling for form, evidenced in the remains of 
classic art, had not even the most primitive power of observa- 
tion, we may mention the following. According to the elder 
Pliny, whose estimate is very much higher than those of Hippar- 
chus and Ptolemy as recorded in the Almagest, the number of fixed 
stars is 1,600; whereas, in our own day, Argelander, working in 
such a comparatively unfavourable climate as Bonn, records on his 
maps no less than 3,256 stars visible to the naked eye. Again, 
Argelander gives nineteen as the number of nebulz and star- 
clusters visible in our latitudes, while Hipparchus mentions 
only two, and Ptolemy but five ; both of these observers entirely 
passing over such remarkable objects as the nebule in Orion 
and in Andromeda. The group of the Pleiades was considered 
of great importance for ancient navigation, and was constantly 
watched; and yet only seven of its stars were discovered. 
Indeed most of the early observers could only see six; the 
seventh was lost sight of for centuries; and ultimately, when 
the middle star in the tail of the Great Bear first attracted atten- 
tion, the conclusion arrived at was that the latter was the 
missing seventh star of the Pleides. Nowadays cases are known 
of people who are not astronomers seeing from fourteen to 
sixteen stars in the Pleiades ; and it is by no means uncommon 
for persons of good sight to see eleven. The star w in Capri- 
cornus was seen by man for thousands of years without its 
being noted that it is a double star, a fact that any child 
would discover now if its attention were directed to it. It 
would be interesting to know what is the capacity of indivi- 
duals of savage races as regards discriminating celestial objects. 
Light might then be thrown upon the question, how far the 
observational defects of the early astronomers were due to mere 
carelessness, and how far we inherit a schooled eye from gene- 
tions of ancestors who gradually accustomed themselves to the 
accurate discrimination of external objects. 
SOCIETIES AND ACADEMIES 
LONDON 
Royal Society, December 9.—Dr. W. A. Miller, V.P., in 
the chair. The following papers were read :— 
‘«Spectroscopic Observations of the Sun.”—No. V. By J. 
Norman Lockyer, F.R.S. 
The author first referred to several new facts of importance as 
follows : 
“T. The extreme rates of movement in the chromosphere 
observed up to the present time are— 
Vertical movement 
Horizontal or cyclonic movement. 
40 miles a second 
120 a 
“TI. T have carefully observed the chromosphere when spots 
have been near the limb. The spots have sometimes been ac- 
companied by prominences, at other times they have not been so 
accompanied. Such observations show that we may have spots 
visible without prominences in the same region, and prominences 
without spots ; but I do not say that a spot is not accompanied 
by a prominenee a¢ some stage of its life, or that it does not result 
from some action which, in the majority of cases, is accompanied 
by a prominence. 
“TIT. At times, when a prominence is seen bright on the sun 
itself, the bright F line varies considerably, both in thickness 
and brilliancy, within the thickness of the dark line. The ap- 
pearances presented are exactly as if we were looking at the 
prominences through a grating. 
“IV. Bright prominences, when seen above spots on the disk, 
if built up of other substances besides hydrogen. are indicated 
by the bright lines of those substances in addition to the lines of 
hydrogen. The bright lines are then seen very thin, situated 
centrally (or nearly so) on the broad absorption-bands caused by 
the underlying less-luminous vapours of the same subs'ances. 
“WV. Ihave at last detected an absorption-line corresponding 
to the orange line in the chromosphere. Father Secchi states* 
that there is a line corresponding to it much brighter than the 
rest of the spectrum. My observation would s-em to indicate 
that he has observed a bright line less refrangible than the one in 
question, which bright line is at times excessively brilliant. It 
requires absolutely perfect atmospheric conditions to see it in the 
ordinary solar spectrum.. It is best seen in a spot-spectrum 
when the spot is partially covered by a bright prominence. 
“VI. In the neighbourhood of spots the F bright line is 
sometimes observed considerably widened out in several places, 
as if the spectroscope were analysing injections of hydrogen at 
great pressure in very limited regions into the chromosphere. 
“VII. The brilliancy of the bright lines visible in the ordinary 
solar spectrum is extremely variable. One of them, at 1871°5, 
and another, at 1529°5 of Kirchhoff’s scale, I have detected in the 
chromosphere at the same time that they were brilliant in the 
ordinary solar spectrum. 
“VIIT. Alterations of wave-length have been detected in the 
sodium-, magnesium-, and iron-lines in a spot-spectrum. In the 
case of the last substance, the lines in which the alteration was 
detected were zof those observed when iron (if we accept them 
to be due to iron alone) is injected into the chromosphere. 
“IX. When the chromosphere is observed with a tangential 
slit, the F bright Jine close to the sun’s limb shows traces of 
absorption, which gradually diminish as the higher strata of the 
chromosphere are brought on to the slit, until the absorption- 
line finally thins out and entirely disappears. The lines of 
other substances thus observed do not show this absorption. 
‘*X. During the most recent observations, I have been able to 
detect traces of magnesium and iron in nearly all solar latitudes 
in the chromosphere. If this be not merely the result of the 
good definition lately, it would indicate an increased general 
photospheric disturbance as the maximum sunspot period is 
approached. Moreover, I suspect that the chromosphere has 
lost somewhat of its height.” 
The author appends a list of the bright lines, the position of 
which in the chromosphere have been determined absolutely, 
with the dates of discovery, remarking that in the case of C and 
F his observations were anticipated by M. Janssen :— 
Hydrogen 
C. October 20, 1868. 
F. October 20, 1868. 
near D. October 20, 1868.* 
[* Hydrogen ?—G. G. S.] 
near G. December 22, 1868. 
hk. March 14, 1869. 
Sodium 
D. February 28, 1869. 
Barium 
1989°5+ March 14, 1869. 
2031'2 July 5, 1869. 
Magnesium and included line 
ji 
ral 
B February 21, 1869. 
* Comptes Rendus, 1869, 1 sem. p. 35%. 
+ This reference is to Kirchhofi’s scale. 
