Nov. 16, 1882 | 
NATURE 53 
Magnetic Arrangement of Clouds 
THERE is a small literature on the above subject (dating back 
to the time of the publica'ion of Humboldt’s Cosmos) which seems 
to have escaped the attention of Mr, Romanes. He will find a large 
number of observations similar to those mentioned in NATURE, 
vol. xxvii. p. 31, recorded in a paper in the P/:/. Mag. for July, 
1853, by Mr. W. Stevenson, of Dunse. Similar observations 
have been made by Mr. Birt, Ae’. Wag. January, 1876, and by 
several others in this country. M. André Poéy also deals with, 
the subject at some length in his work, ‘‘ Comment on observe 
les Nuages,”’ chap. iv. 
Theapparent arrangement of cirri-form clouds “round two oppo- 
site poles” is simply the optical effect of the parallelism of the belts 
of ice-cloud, or ‘‘ cirrus-band:,” as Humboldt designated them. 
These belts are coincident in direction with what were, at the 
time of the formation of the clouds, lines of eqnal pressure in 
that horizontal plane in which the clouds float; or, in other 
words, their direction is normal to that of the atmospheric gra- 
dient at the cirrus-level, Their position, and therefore that of 
their vanishing points, has never been proved to have any rela- 
tion to the position of the magnetic poles. It is true that in 
Europe a direction coincident with the magnetic meridian is 
slightly more common than a direction transverse thereto. But 
this is explained hy the fact that the formation of the bands 
requires somewhat steep gradients in the regions of the cirrus, and 
that, with us, the steepest gradients in those regions are commonly 
the north-eastward, being those which prevail in front of and 
between the cyclonic disturbances at the earth’s surface, which 
travel towards north-east. Thus, the best defined cirrus-bands 
most commonly stretch from north-west to south-east. 
A detailed explanation of the formation of the belts, which 
bears some similarity to that given by Lamarck, and which is in 
many, but perhaps not in all points satisfactory, will be found in 
a paper by Max Moller in the ‘‘ Annalen der Hydrographie und 
Maritimen Meteorologie. Organ des Hydrographischen Amtes 
und der Deutschen Seewarte,’’ 1882, heft iv. pp. 212-226. 
The attem) ts which have been frequently nade to apply the 
terms ‘‘ polarisation,” ‘‘ polar bands,” &c , to the cirrus belts 
have proved unsuccessful, and will not, it is to be hoped, be 
renewed. W. CLEMENT LEY 
November 11 
*©A Curious Halo” 
THE phenomenon described in Nature (vol. xxvi. pp. 268, 
293, xxvii. p. 30) is far from being unknown in Europe, where 
it generally receives the title of ‘‘ Rayons du Crépuscule” ; 
although I do not think that it ever presents the brilliant appear- 
ance described by Father Mare Dechevrens as noticeable ia 
China. In England it is more common in the winter than in 
the summer months, and does not appear to occur especially in 
warm weather, although I do not know tbat it has been noticed 
during frost. The furrows between the bands of light are not, so 
far as I have observed, rapidly movable in the sky in England, 
and they seem to be traceable to hills beneath the horizon, rather 
than to cumuli. I have never noticed them where the sun sets 
beneath a sea horizon. W. CLEMENT LEY 
The phenomenon described by M. Dechevrens as often wit- 
nessed in China, I have several times seen in this country, 
namely, beams or spokes in the eastern sky about sunset, spring- 
ing from a point due opposite to the sun, The appearance is 
not very strongly marked, and I used to think I must have been 
mistaken, till I came to see the true explanation, which was the 
same as that furnished by your correspondent. 
There seems no reason why the phenomenon should not be 
common, and perhaps if looked out for it would be found to be. 
But who looks east at sunset? Something in the same way 
everybody has seen the rainbow; but the solar halo, which is 
really commoner, few people, not readers of scientific works, 
have ever seen at all, The appearance in question is due to 
cloud-shadows in an unusual perspective and in a clear sky; 
now shadow may not only be seen carried by misty, mealy, 
dusty, or smoky air near the ground, but even on almost every 
bright day, by seemingly clear air high overhead. Therefore, if 
this sunset phenomenon is much commoner in China, there must 
one would think, be some other reason for it than that the sky 
of England is not heavily charged enough with vapour to carry 
shadow. Rather it is too much charged, and the edge of the 
shadow becomes lost with distance and with the thickening of 
the air towards the horizon before the convergence of the beams 
eastwards is marked enough to catch the eye. 
I may remark that things common at home have sometimes 
first been remarked abroad. ‘The stars in snow were first ob- 
served in the polar regions ; it was thought that they only aro:e 
there, but now everyone sees them with the naked eye on his 
coatsleeve, GERARD Hopkins 
Stonyhurst College 
Priestley and Lavoisier 
I AM sorry that Mr. Rodwell should have thought it necessary 
to revive the old oxygen quarrel, and the more so, as he has 
taken an unpatriotic part against Priestley, and indor ed the 
complacent statement of Wurtz, that chemistry is a French 
science founded by Lavoisier ; forgetting, perhaps, that the title, 
“*La Chimie Frangaise,” was invented by Fourcroy, and objected 
to by Lavoisier. 
The fact is, that chemistry has no nationality. It belongs to 
the universal republic of Nature, and had no proper existence 
for us until Dalton discovered its laws. 
In the scientific democracy, to ue Lord Bacon’s expression, 
discoverers are mutually dependent, and it would perhaps be 
impossible to find any o.e capable of standing alone. It has 
even been charged against our great Newton that his astrono- 
mical discoveries are to be found in Kepler; but, as Dr. 
Whewell well remarks, it required a Newton to find them there. 
That the compound is always equal to the sum of its elements, 
was known long before Lavoisier, and so early as 1630 Rey gave 
the true explanation of the increase of the weight of metals by 
calcination. Lavoisier’s note of 1772 was, as he admitted, 
based upon Priestley’s earlier experiments, begun in 1744 ; while 
the acceptance of Lavoisier’s doctrine was mainly due to the 
capital discovery of the composition of water by Cavendish, iu 
1734. 
If at this advanced period we are required to put in national 
claims, then surely our own countrymen must share largely in 
the honours which Mr. Rodwell reserves for Lavoisier alone. 
Black, Priestley, and Cavendish are the founders of pneumatic 
chemistry. Priestley discovered oxygen in 1774, Cavendi-h 
discovered hydrogen in 1784, while Davy abjured La voisier’s 
principe oxygene, and by his numerous discoveries gave the che- 
mical edifice so rude a shake, that it had to be taken down and 
rebuilt. C. TOMLINSON 
Highgate, N., November 4 
Wire Guns 
IN the last number of NATURE there is an interesting paper 
on ‘* Wire Guns,” and incidentally various methods of manu- 
facturing guns is mentioned. <Afrofos of this permit me to 
relate a curious fact regarding gunmaking which came under 
my notice many years ago, and which supports the adage that 
there is nothing new under the sun. In the autumn of 1841 Sir 
H. Gough took the batteries of Chusan by a turning movement 
and thus spoiled the Chinese preparations. The force captured 
a large number of gans, some very fine bronze ones, but there 
were also a good many smaller iron ones, and as these were of 
no value they were ordered to be destroyed. The Royal Artil- 
lery tried to burst these without success at first, and only after 
sinking the muzzles in the ground did they succeed. {ft was 
then ascertained that the reason of the extreme strength of the 
gun arose from its strange manufacture. It had an inner tube 
of wrought iron, over which the gun was cast, anticipating by 
many years a somewhat similar plan by Palliser. 
Cheltenham, November 3 Wi, EL, (©. B: 
Paleolithic River Gravels 
Mr. C. Evans, in NATuRE, vol. xxvii. p. 8, wishes our 
anthropologists to furnish an explanation why the mortalremains 
of paleeolithic man are not to be found amongst his ‘‘ so-called 
* flint implements.’ ” 
The question is one that naturally occurs to any one whose 
practical acquaintance with anthropological ‘‘finds” is of a 
limited character; and it may fairly be presumed that the 
inquirer has not himself seen and handled such relics, else he 
would scarce“y have imagined it within the range of possibility 
that they could have been ‘‘ formed by natural causes,” by 
which, I suppose, he wishes to infer that they were not made 
Ty man, 
