Fan. 6, 1870] 
NATURE 
267 
which they have been subjected on their downward course ; but, 
at the same time, he distinguishes between these veins—the 
result of stratification, and others which he terms bands of 
infiltration, and which he believes to have been formed by the 
infiltration and freezing of water. 
The late Principal J. D. Forbes maintained (‘‘ Occasional 
Papers on the Theory of Glaciers,” 13th letter) that the veins 
of stratification were annihilated at a certain point, and that 
at precisely the same time other veins, approximately at right 
angles to the former ones, were formed. These effects he 
referred to intense pressure. 
Professor Tyndall (‘‘ Glaciers of the Alps,” pp. 380, 425-6), 
agrees with Professor Forbes ‘‘in ascribing to the structure a 
different origin from stratification,” and, if I understand him 
rightly, does not believe that azy portion of the (approximately) 
vertical veins have such an origin. He divides the veins into 
marginal, transverse, and longitudinal structure, and asserts that 
all are produced by pressure, which causes partial liquefaction of 
the ice, and that the water is refrozen when the pressure is 
relieved. 
If any one cause produced the whole of the veins of pure ice 
that are found in the imperfect ice of glaciers (which all are 
agreed are a constitutional feature of those bodies), it is obvious 
that that cause would have to be equally generally distributed. 
It is indisputable that all the veins are not veins of stratification, 
because examples have been frequently observed crossing (cutting) 
the strata lines at a larger or smaller angle. But although such 
observations prove conclusively that all the veins must not be 
attributed to stratification, they do not prove any more. I 
believe, with Professor Agassiz, for reasons advanced elsewhere, * 
it can be demonstrated, equally conclusively, that many of the 
veins which are seen in the lower courses of glaciers in the Alps 
are veins originally produced by stratification, and dissent entirely 
from the ‘‘annihilation” of Principal Forbes. But as it is 
proved that some have a different origin, we must look to other 
causes for an explanation. It is probable that the theories 
quoted above offer a practical solution of the difficulty, although 
they are unfortified by direct proofs. But I have seen examples 
which it was difficult to explain by either one or the other. 
There is one means by which the veins might be produced, 
which, if not overlooked, is at least not generally advanced. All 
glaciers have crevasses ; a glacier is known byits crevasses. The 
sides of al] crevasses become more or less weathered and coated 
with a glaze of pure ice. When they close up again, when the 
sides join by virtue of regelation, does this leave no trace? Can 
it beannihilated? Or, do the two coalesced films leave their mark 
as a vein of pure ice throughout the generally whitish mass of the 
glacier? I consider a large number of the veins of pure ice which 
constitute the ‘‘veined structure” of glaciers as nothing more 
than the scars of healed crevasses. 
It is not easy to say whether this was the meaning of the follow- 
ing passage, taken from p. 201 of Forbes’s ‘* Occasional Papers :” 
“* Most evidently, also, the icy structure is first induced near the 
sides of the glacier where the pressure and working of the interior 
of the ice, accompanied with intense friction, comes into play, and 
the multitudinous incipient fissures occasioned by the intense strain 
are reunited by the simple effects of time and cohesion.” Judged 
by his preceding pages, itis not, and Iam unaware that it has been, 
advanced in any other place. Some of your readers may perhaps 
be able to throw some light upon the subject. 
Dec. 13, 1869 EDWARD WHYMPER 
Irish Lepidoptera 
In reply to the note appended to the report of the Dublin 
Natural History Society’s Meeting, Dec. 1st (NATURE, No. 6, 
-p. 176), allow me to say that I perfectly remember the specimen 
of Ziminitis to which Mr. Andrews refers, and which he exhi- 
bited some years ago as Zzminitis Stbylla from Tarbert in the 
county of Limerick. It was subsequently given by him to my 
friend Mr. A. Dunlop, of Sutton, near Dublin, and sent to me 
for identification. 
I examined it carefully, and it is a specimen of Limzdnitis 
Camilla, and of Continental origin. ow it came to be mixed 
with Mr. Andrews’s Irish specimens remains for him to explain. 
To say that the insect is neither Sibylla nor Camilla is absurd ; 
these are the only two species of the genus which inhabit Europe ; 
and Camilla, to which Mr. Andrews’s specimen belongs, is the 
most unlikely of the two to occur in Ireland, as Sybilla is found 
in England, but not Camilla. However, the insect is in Mr. 
* British Association, 1866 (Nottingham). 
Dunlop’s Collection, and I am sure that gentleman will haye 
pleasure in allowing anyone to inspect it. 
As to Chrysophanus Virgaurea, there is no British specimen 
known, nor is there any trustworthy record of the capture of the 
species in the British Islands. 
Chrysophanus Hippothoe (variety Disfar) was formerly taken 
in profusion in the fen districts of Cambridge and Hunting- 
don, but not that Iam aware of in any other part of England. 
It has been extinct for many years as a British insect, and there 
is no record of its capture in Ireland at any time. Mr. Andrews’s 
statement that he ‘‘met with” Dispar in Kerry is indefinite. 
Did he capture it? or did he only see it, or suppose he saw it? 
The most experienced collector may mistake an insect on the 
wing; and delighted as entomologists would be to welcome back 
the long-lost Hippothoe, they will require very different proof of 
its reappearance to any which has yet been adduced. 
EDWIN BIRCHALL 
Airedale Cliff, Newlay, near Leeds, Dec. 20, 1869 
Deep Sea Corals 
In the postscript to Mr. J. Gwyn Jeffreys’s report on the 
“ Deep-sea Dredging ExpeditioninH.M.S. Porcupine,” I notice 
the following sentence :—* The presence of corals at great depth 
will also materially alter the views generally received of the 
depth at which reef-builders may work, and modify to a 
certain extent Darwin’s theory of the reefs and their mode of 
growth.” This opinion hasgained muchcredence, but itis founded 
upon error, and is a mistake. Count Pourtales has been good 
enough to send me the commonest corals which he dredged 
up off Florida and the Havana from depths greater than 100 
fathoms. He has forwarded also the description of the species, 
and a note upon the nature of the gevera represented in the 
depths of the Gulf of Mexico, and which have not been as 
yet described. I have received the greater part of the corals 
dredged up during the expedition in the Porcupine, and have 
examined the specimens carefully. Being thus acquainted with 
the deep-sea coral fauna of both sides of the Atlantic, and 
having a previous knowledge of the species of the Mediterranean, 
I have no hesitation in asserting that there is not one species 
found in these deep seas which is ‘‘ reef-building”’ in its habit or 
whose structures resemble those of the true reef forms. Mr. 
Darwin’s theory is therefore as yet as strong as ever. 
Dec. 23, 1869 P. Martin DUNCAN 
A Meteor 
My attention has just been called to an error in my letter 
of November 6, which appeared in NATURE, p. 58, respect- 
ing the meteor of that evening. I refer to the statement that, 
of the meteor-cloud, the ‘‘longest axis was in the line from the 
north-west point of the horizon to the pole-star.” Instead of 
north-west, it should have been sowth-west, or, perhaps, more 
correctly, S.W. by W. Wn. PENGELLY 
Lamorna, Torquay, Dec. 31, 1869 
NOTES 
THE trigonometrical survey of England and Wales, on the scale 
of one inch to a mile, has been completed during the past week. 
It was commenced in the year 1791. 
TELEGRAPHIC connection with Australia is about to be carried 
out by the British-Australian Telegraph Company. The work 
will consist of 563 miles of cable from Singapore to Batavia, 
and will join the Dutch line which crosses to the south-eastern 
extremity of Java, from which point another cable of 1,163 miles 
is to be laid to Port Darwin. A land line of about 800 miles will 
connect this with all the Australian colonies. From England to 
Singapore the messages will be taken by the Falmouth and 
Malta, the Anglo-Mediterranean, and the British-Indian Exten- 
sion Companies; thus forming a complete route. 
THE eighth part of Wurtz’s Dictionnaire de Chimie has just 
been issued. The Revue des Cours Scientifigues, to which we are 
indebted for this announcement, calls particular attention to the 
articles Laux and Composés diazotgues by M. Gautier, Dzssocia- 
tion by M. H. Debray, and Exgrais by M. Deheérain. 
Tue Agricultural Academy of Poppelsdorf, near Bonn, has 
recently sustained a seyere loss in the death of its able and ener- 
