Aug. 25, 1870] 
NATURE 
347 
gian Academy of Sciences, a translation of which has already 
been published in this country. The current number for August 20 
opens with an article 2 frogos of the war, a translation of Prof. 
Shaw’s address to the Military College at Sandhurst on the war 
establishments of Great Britain. We have then the continuation 
of M. Marey’s paper on the Flight of Birds ; and, in conclusion, 
under the head of ‘ Bibliography,” a translation of Mr. Wallace’s 
review of Mr. J. J. Murphy’s ‘‘ Habit and Intelligence,” which 
appeared in our columns. 
THE American Entomologist and Botanist publishes a double 
number for July and August, which is occupied by short descrip- 
tive articles of interest and value principally to American col- 
lectors and students. The article of chief general interest is one 
on the ‘‘Origin of Prairie Vegetation,” consisting of an able 
criticism of Prof. Winchell’s theory that the prairies are of 
lacustrine origin, and that we must look to the source of the 
prairie vegetation from without,—probably the remains of a pre- 
glacial flora, the germs of which have remained stored up during 
subsequent epochs, and come again to life whenever the diluvial 
surface is again exposed. The writer of the article maintains 
that there is no need to go so far back as the diluvial period for 
the origin of the prairie vegetation. Dr. Hale, of Chicago, 
mentions the interesting fact that the Ranunculus cymbalaria, an 
abundant plant of the eastern sea coast and of the salt springs 
in the State of New York, is found in great abundance at 
Chicago, and for several miles along the shores of Lake Michigan, 
though nowhere else on the Great Lakes. It appears, however, 
that it also grows on the muddy banks of some of the western 
rivers. 
THE Geological Magazine for the present month (No. 74), 
contains only three original articles, namely, one by Mr. D 
Mackintosh on the Dispersion of Shapfell Boulders, and Origin 
of Boulder Ciay; a second by Mr. John Hopkinson on the 
structure and affinities of Dicranograptus (with a plate), includ- 
ing descriptions and figures of the British species of that genus, 
two of which (D. formosus and D. nicholsoni) are described as 
new; and a memoir, with two plates, by Mr. T. Davidson, on 
Italian Tertiary Brachiopoda, with an important table of the 
species and their geological distribution. Among the abstracts 
and notices of memoirs, is a report of an interesting lecture on the 
Primzeval Rivers of Britain, by Professor T. Rupert Jones. 
Mittheilungen aus Sustus Perthes Geographischer Anstalt 
(vol. xvi., No. 8) opens with a remarkably interesting paper 
—illustrated by a map—by Dr. G. Nachtigal, on his travels 
-in Tibesti. He says that, in spite of Barth’s philological 
investigations, he regards the question as to the nature of the 
Tibbu as still undecided. They are of middle height, are very 
well built, and possess elegant yet muscular limbs. The majority 
of themare of a deep bronze colour, but without a trace of 
what is usually termed the negro physiognomy. On the whole, 
their physical and psychical peculiarities, their social and poli- 
tical arrangements, and their manners and customs, resemble 
those of the Berber infinitely more than those of the Negro. 
Amongst other things, Dr. Nachtigal records some careful obser- 
vations of the rivers Zuar and Marmar, the former of which he 
regards as incomparably the finest river in Tibesti. In M. 
Lejean’s article on his own travels in European Turkey in 1869, 
he corrects the existing maps in several points, embodying in an 
elaborate map the results of his investigations. He expresses 
the greatest contempt for the modern Turks, intimating that 
those who believe they have recently made real progress are 
deceived by mere appearances. He says he has gathered full 
materials for a work or works on the ethnography and archzology 
of the districts he describes. Professor Pellegrino Strobel 
describes a journey from the Planchar Pass to Mendoza; and 
the rest of the number is made up of ‘‘ Geographical Notices” 
and translations of extracts from Mr. Robert Brown’s ‘“‘ Phy- 
sical Geography of the Queen Charlotte Islands,” and from re- 
ports published in the “‘South Australian Register,” on Mr, 
G. W. Gogden’s Measuring Expedition to North Australia. 
SOCIETIES AND ACADEMIES 
BRISTOL 
Observing Astronomical Society.— Report of observa- 
tions made by the members during the period from July 7th to 
August 6th, 1870, inclusive :—Solar Phenomena.—Mr. Thomas 
G, E. Elger, of Bedford, reports that the sun spots observed in 
July exceeded in number those recorded during the previous 
month, but they were, with a few exceptions, small (less than 
30" in diameter), and although pretty equally distributed between 
the two hemispheres, those to the south of the sun’s equator 
presented a remarkable contrast, both in type and size, to those 
observed to the north of it; the former, as in June, included 
some large scattered groups and moderately sized spots of the 
normal class, while the latter consisted chiefly of solitary specks 
without penumbree, and clusters of minute black punctures which 
frequently assumed very grotesque configurations. <A striking 
feature of the large groups observed during the early part of the 
month was an evident tendency either to close up or to become 
dissociated upon reaching a certain position on the disc—about 
half way between the E. limb and the centre. On the 25th one 
of the largest groups observed this year appeared at the E. limb ; 
on the 28th it measured nearly 5’ in length, and consisted of a 
large preceding spot 1’ 10” in diameter, followed by a straggling 
train of ‘‘ wispy” penumbrz enclosing several small spots. 
This group dwindled away very rapidly after the 28th. Another 
large spot, about 50” in diameter, was observed from July 13th— 
25th. 
Fresh groups observed in the sun’s N. hemisphere during 
July . é < : c : : . 
Fresh groups observed in the sun’s S, hemisphere during 
ijtil yews . F a : > 6 - 12 
Maximum number of groups on disc . 12 
(July 13, 5" 30") 
c : ogi 
(July 28, 5 10") 
Mr. Albert P. Holden, of London, says, ‘‘I observed a very 
interesting spot on June 21, at 7 A.M. The penumbra was 
unusually pale, and the umbra of a decided light brown hue. 
Four darker openings arranged in a square were observed in the 
umbra, and were readily seen with a very small aperture. A 
very remarkable circumstance in connection with the sun spots 
during the last two months has been their extremely light 
colour. The light brown tints of the umbra have been very 
marked, and totally different from the dark hues they usually 
present ; while, at times, the penumbrz have been so light as to 
be scarcely visible. In most of them, however, the nucleus 
(which is ordinarily so difficult to detect) has been very easily 
seen, as in the case of the foregoing observation. The fact 
proves the phenomenon seen to be due to the actual lightening 
of the spots themselves, because if it were merely an optical or 
atmospheric effect, the whole spot would be lighter and the 
nucleus would be quite as difficult to detect as before. It is 
probable that these appearances may be a necessary result of the 
maximum of sun-spot activity, and are due (as suggested by Mr. 
Lockyer) to the thinness of the solar envelope at the present 
time. This would certainly account for the light hues of the 
umbrz and penumbree, and also for the frequency and blackness 
of the nucleus.” Mr. Henry Ormesher, of Manchester, writes, 
‘On: the 3ist of July, from 28 15™ to 3% om, while 
looking at the sun with my 3in. refractor, I saw a beau- 
tiful large cluster of spots occupying an almost central 
position on the disc. It occurred to me that the umbra 
in the largest spot appeared more dense on the western side. 
I therefore determined to examine it with my 54in. refractor. 
I did so, using a power of 181. The result was that it resolved 
itself into a very fine nucleus of a somewhat oval shape. After 
making myself sure that the above was the case I examined the 
cluster generally, and was struck with the beautiful appearance 
of the brighter part of the sun’s atmosphere. A very bright 
stream ran across the cluster, in a zigzag direction, separating 
the penumbra. Some parts of this stream, and particularly the 
upper part, appeared brighter than others, presenting a very 
mottled appearance.”—Mr. William F. Denning, of Bristol, 
observed the sun, with his 3in. refractor, on July 14, from 
5" 30™ to 64 10™, He noticed nine large well-defined macule 
on various parts of the disc. A particularly large and interest- 
ing grcmp of spots was visible inthe N. hemisphere. On July 22, 
at 8 P.M., a spot was observed in the same hemisphere, which 
was divided by two bridges of light. He noticed that the 
penumibra was invaded by numerous minute lines of light, and 
that the bridges seemed to present the appearance of running 
matter. This observation was made with power Ioo and 
10} in. reflector by Browning. 
The Lunar Eclipse of Fuly 12.—The Rey. Ralph Prowde, of 
Northallerton, Yorkshire, observed this phenomenon, and has 
forwarded the following :—“‘I observed the eclipse of the moon 
Minimum number of groups on disc 
