204 
pation of Bremen by the French, under the rapacious 
and unscrupulous Vandamme, the story of which we may 
allow the sufferer to relate in his own words. 
“Through the most barbarous fury, in consequence of 
an equally barbarous sentence, the whole unoffending 
soft “vale of lilies’’ (Lilienthal) was, without previous 
inquiry, destroyed by fire. Without possibility of suc- 
cour, they burnt down also the Royal Government offices ; 
I lost the whole of my furniture, and what was most 
distressing of all, with a considerable damage also to the 
bookshops of Europe, the sole stock of my collected 
works and writings laid up in the government buildings. 
Even my observatory, preserved by Providence from the 
conflagration, was a few days afterwards broken into, 
plundered, and through the destruction of the clocks, 
breaking off of the finders, and robbery of the smaller 
instruments, scandalously ruined. Having been displaced 
from my post, my income had been previously by degrees 
so very much reduced, that I was compelled to forego 
everything but absolutely necessary expenditure, and to 
be laid aside in a scientific slumber.” Elsewhere he 
says that even his journals had perished; and at the 
date of writing the introduction to his ‘‘ Observations and 
Remarks upon the Great Comet of 1811” (January 22, 
1815), from which the foregoing passage is taken, he 
complains that his circumstances were still so reduced, 
that his observatory, for want of time and money, re- 
mained for the most part in a state of confusion. So 
great are even the minor miseries of those ‘‘ wars and 
fightings,’’ of which many speak with such apathetic un- 
concern. Itis painful to add to these sad details that this 
seems to have been Schréter’s final effort, for after a 
twelvemonth of bodily and intellectual decay, he expired 
August 29, 1816, leaving behind him a worthy memory, 
to which, till of late years, our own country has done but 
inadequate justice. 
The “Areographische Beitrage” remained in MS. at 
his death, having escaped the calamitous fire, but so 
narrowly, that two out of the sixteen copper plates of 
figures had to be engraved again ; no idea seems to have 
been entertained of publication, but they were safely pre- 
served by the author’s family. Their existence having 
been ascertained many years ago, by the present writer, 
through the kindness of Dr. Peters of Altona, a negotia- 
tion was set on foot for their acquisition by the Royal 
Astronomical Society; this proved ineffectual; but, in 
consequence of the attention directed to them, they were 
allowed to be inspected by Dr. Terby, to whose able and 
comprehensive analysis of the MS. as published in the 
Memoires of the Belgian Royal Academy of Sciences in 
1873, the present notice is deeply indebted ; and astro- 
nomers will be glad to learn tnat they have now been pur- 
chased by the University of Leiden for the library of that 
observatory, and that, after an obscurity protracted 
through seventy years, they have at last been published in 
a complete and handsome form, under. the able and 
accurate editorship of the director of that institution. 
The work, though characterised, like other productions 
of the same author, by a needless amount of prolixity, is 
well deserving of careful study, as indicating or confirm- 
ing some valuable conclusions, and affording material for 
suggestive thought. The whole observations are per- 
vaded by an impression that the obscurer portions of the 
disc are condensations in a vaporous atmosphere. The 
author, with a singular misconception of terrestrial 
analogy, supposes throughout that such cloudy masses 
viewed on their upper or enlightened side would appear 
darker rather than lighter than the surface beneath them ; 
admitting at the same time that the configuration of that 
surface may so modify the superjacent atmosphere, as to 
cause a permanence, or, at any rate, recurrence of 
vaporous formation, from which the rotation may be, and 
has been determined. The occasional invisibility of dark 
spots, which has been recorded by too many observers to 
NATURE 
[ Dec. 28, 1882 
be brought in question, would be explained by Schroter 
in accordance with this theory, and may possibly be due 
to atmospheric causes; though, as Terby has pointed 
out, it may often have arisen from the difficulty of tracing 
any markings in the neighbourhood of the limb. It is 
more difficult to account satisfactorily for the movements 
ascribed by Schroter to the action of winds, of which he 
has specified in an elaborate table no less than forty-six. 
instances, not much differing in velocity from those on 
earth, and in the great majority of cases conspiring with 
the direction of the rotation. Error may have crept in 
with regard to the identification of some of the spots ; 
and both from the designs and descriptions a suspicion 
arises that some of the minuter details, which now serve 
for the recognition of distinct but similar regions, escaped 
the observer’s notice. There must have been some cause 
for this unfortunate defect which detracts materially from 
the value of his work, and the removal of which would 
have been the one step in advance which, as Terby 
remarks, would have put him in possession of the true 
interpretation of what he saw. It would be a ready 
explanation to refer it to the imperfect defining power of 
his instruments ; and I have somewhere read of a com- 
parison instituted after his time between his much-prized 
speculum of 93 inches aperture and 123 feet focal length, 
and a Fraunhofer object-glass of, I think, about 4 inches, 
to the disadvantage of the former. Yet on the other hand 
he began his work with telescopes by the elder Herschel : 
and his 7-foot instrument by this great maker does not 
seem to have been superior to that of the same dimen- 
sions by Schrader, the manufacturer of all his larger ones. 
This point is therefore not quite clear. We might have 
attached some importance to his own admission, in his 
work on the moon, that his vision was less microscopic 
than that of his assistant, Harding, but for the fact that 
the latter occasionally aided him in these observations on 
Mars. Whatever may have been the cause, the frequent 
absence of minuter detail must have served to confirm 
Schréter’s misapprehension of what he saw. And it 
must be borne in mind, in estimating his observations in 
general, that it was his habit to undertake investigation 
with a preconceived idea. In the case of the moon, his 
prepossession in favour of changes no doubt occasionally 
misled his judgment ; and on Mars he might be prepared 
to look out for atmospheric movement by the known 
phenomena of Jupiter. An anticipation of this kind may 
not be without incidental advantage in directing and 
sharpening attention: our search may be aided, and with 
perfect fairness and honesty, by the foresight of the 
result: but at other times such expectations may be 
equally or more prejudicial; and they probably were so 
in the instance before us. And it isat any rate a possible 
suggestion that, with regard to some of these supposed 
changes, Schréter’s ideas may have been unconsciously 
biassed by his study of the surface of Jupiter. The per- 
spective foreshortening of that great globe having no 
effect on the aspect of its more conspicuous and familiar 
markings, from their equatorial direction, and being non- 
apparent in the transits of the shadows of the satellites, 
the eye may come to regard it too much as a flat disc, 
and to appreciate too little the extensive changes which 
mere foreshortening produces among markings arranged 
in any other direction. 
But whatever explanation may be attempted of Schréter’s 
illusion, which, as his editor remarks, increases the value 
of his figures by securing their perfect independence, or 
however we may regret an apparent want in some cases 
of more distinctive detail, there can be no doubt that the 
work is worthy of attentive study. Dr. Terby has pointed 
out one curious inference —that at that epoch certain dark 
markings bore a relative proportion to each other, too 
different from that which obtains at present to be easily 
explained away. Nor does this result by any means 
stand alone; and it has considerable value as -affording 
