348 
NATURE 
[March 2, 1871 


The Exeter Museum 
Tue paragraph in NaTuRE or the 23rd ult, respecting the 
Royal Albert Museum at Exeter, has excited my curiosity. 
Will you be so good as to mention an instance or two in proof 
that the museum ‘‘has done much towards attracting attention to 
the value of scientific knowledge in the West of England ?” 
It is difficult for a stranger to see how the case of the Plympton 
Grammar School can be ascribed to its influence. 
Feb. 25 INQUIRER 
Aurora Australis 
[Extract from a letter received_from Captain H. P. Wright, 
Ship Gasfarth] F 
Madras, Dec. 5. 
J ENCLOSE you an account of the Aurora Australis as we saw 
it in the South, and I might also state that Mr. Pogson (Madras 
Observatory) says that the magnetic disturbance in these two 
days, 14th and 25th October, was so great that his instruments 
would not register the amount, 
(Signed) H. P. Wkicur 
« October 24, 1870.—New moonat 6 P.M., lat. 42°S., long. 39° 
E. ; at 7.30, as the twilight began to fade in the sky, we observed 
a bright rosy light at first resembling the reflection from a very 
red fire in the southern heavens. It extended from W. to E., 
and was visible from 8° to 50° high, being brightest at about 35° 
or 40°. Bright stars of the first and second magnitude shone 
through it. This cloud of crimson light had nearly all faded 
away by 9 P.M., first in the south-western direction, and so on 
gradually to the south-eastward. It may have been blown along 
by the wind, which was N.W. by W., but I did not think so. 
Other light clouds were passing; the sky below was its usual 
colour, and the stars shining very low down. As soon as this 
had passed away, there came a yellowish white, or milky white, 
light in the southern sky, and, as it were, taking the place of the 
crimson light. I should guess it to be about equal to % of the 
moon s light, and showing a little bank of clouds of a dark-grey 
colour some 4° or 5° above the horizon underneath. This con- 
tinued until 10.40 P.M., when it suddenly assumed a grander 
appearance. There was one long line of the brightest crimson 
some 8° or 9° broad, reaching up from south towards north, and 
some 70° high, fading into the normal colour of sky ; this rose 
up a little to the west of the Southern Cross, on from this to the 
eastward was a great cloud or clouds of this bright crimson light, 
the bright star Canopus &c. showing through with a deep 
yellow light, and, passing over all, cumulus clouds carried some- 
what quickly by the brisk breeze then blowing. To give, per- 
haps, a better estimate of the yellowish-white light, we could as 
long as it lasted only see the stars in the Southern Cross indis- 
tinctly. By midnight, or a little after, it all passed away, and 
we had lightning to the S.W. in the middle watch. The follow- 
ing night was very rainy, but the strong crimson‘ and white light 
could still be discerned.” 

Aurora by Daylight 
In Nature of Dec. 15, a correspondent asks the question, 
Can Aurora be seen in daylight?” I answer, yes, beyond a 
doubt. In the autumn of last year (I cannot give the date 
nearer than that it was early in Ooctober) my eye was attracted 
by an unusual motion, in what at the first glance appeared to be 
a light fleecy cloud, but was in reality a broad ribbon of Aurora 
of a yellowish white colour, which changed its form and position 
with the peculiar streaming motion of the Aurora, sometimes 
almost fading entirely and again recovering its comparative 
distinctness. 
It was about four o’clock in the afternoon when my attention 
was drawn to it, and I watched until late in the evening, and 
saw it as the dusk came on, supported by fainter streamers of 
light, which stole out as the darkness increased, and almost 
imperceptibly grew into one of those magnificent auroral 
displays so frequently seen here, 
The Aurora, as I first saw it, was about N.W. by N., and I 
should say 30° above the horizon, and the sky was beautifully 
clear and free from clouds, 
Will any of your correspondents inform me if the intensity 
of auroral light, as proved by its visibility in daylight, teaches 
us anything more than is at present known of the Aurora? 
And I should be much obliged to anyone who will inform me 


if the spectrum of lightning has ever been obtained, and if so, 
how it compares with the spectrum of the Aurora. 
W. G. THOMPSON 
Matapediac, Province of Quebec, Feb. 4 
.Tigers at Bay 
In Nature for Feb. 2, p. 275, a doubt is expressed as to 
whether a tiger when in danger will ever take toa tree. Ananec- 
dote related in vol. 2, p. 112 of De Beauvoir’s *‘ Voyage Round 
the World,” seems to settle the question :—‘‘Attacked and 
conquered by the buffalo, the tiger bounded some thirty feet 
into the air into a cocoa-nut tree. Some twenty natives were in 
an elevated position amongst the branches of this tree ; in one 
and the same moment they let themselves fall like ripe fruit 
from a tree that is shaken.” G, E. D, 
Furzewell House, Torquay 
Dr. Donkin’s Natural History of the Diatomacez 
THE reviewer of the above-named work (see NATURE, vol. 
iii., p. 210) describes the plates as inferior to those in the Synopsis. 
With this opinion I fancy many will differ ; as correct repre- 
sentations of the species described, they are far in advance of 
those in the Synopsis, for example, compare the figure of Vazz- 
cula tumens in the latter work with Vavicula rostrata in Dr. 
Donkin’s ; with the exception of the outline, the figure in the 
Synopsis does not resemble that species, and is inferior to Ehren- 
berg’s in the Microgeologie. Also compare WV. Hebes, NV. paipe- 
bralis, N.subsalina, N. latiuscula, N. alpina, with the corre- 
sponding forms in the Synopsis, and I think the superior fidelity 
of Dr. Donkin’s illustrations will be conceded. 
Many of the forms in the Synopsis must have been drawn from 
memory, they are so glaringly inaccurate, ¢.g., dmphipleura pellu- 
cida is represented with marginal punctze, Vileschia bilobata with 
indistinct distant striz. The marginal dots on A. pellucida ex- 
isted only in the delineator’s imagination ; and, as every student 
of the Diatomacez knows, /V. dilobata has close but distinct striae. 
I agree with “ W.” that the synonymy might have been more 
extended. It is, however, next to impossible to identify from 
figures or descriptions the forms intended by the early observers. 
The desirability of giving habitats in full is questionable ; three 
or four localities are sufficient, as with very few exceptions the 
same species would be found (the localities being similar) in any 
part of the United Kingdom. 
In conclusion, I would remark that the following species are 
not Ehrenberg’s, as stated by ‘*W.,” but Gregory’s :—/Vavicula 
Smithii var. fusca ; N. Smithii vax. suborbicularis ; N. Smithit 
var. zitescens, and JV. latissima. 
I know the works of Ehrenberg, Kutzing, Rabenhorst, Grunow, 
and Greville, but who is Cleeve ? 


PROPOSED OBSERVATIONS OF VENUS 
get following circular has just been issued by the 
Observing Astronomical Society :— 
The committee of the society have decided to under- 
take a series of systematic observations of the planet 
Venus, during one complete revolution, for the purpose of 
obtaining results that shall lead to our becoming better 
acquainted with the markings which are visible on her 
surface, and a correct knowledge of their form and per- 
manency. 
In common with other observers it has been to them 
a matter of regret that although this beautiful object 
approaches nearer to us than does any other member of 
the solar system (our satellite excepted), yet that our know- 
ledge of its superficial condition should be far less than 
of those planets less favourably situate. In most astro- 
nomical works the information concerning Venus is very 
meagre, whilst the drawings of her appearance exhibit, 
in the majority of cases, merely a blank crescent. 
Yet, in turning to the ancient observations made of this 
planet, the committee have been struck by the large 
number recorded, many exhibiting well-defined markings, 
and when they considered the numerous observations of 
