344 
of resistance at the temperature of liquid hydrogen was made 
by Dewar on platinum, and he found that the resistance decreased 
to acertain value and then became constant. Thus from this 
result and from the behaviour of bismuth it is not altogether 
unexpected that a rather impure specimen of iron should show a 
definite turning power. 
The present experiments, so far as they go, show that the 
resistance of iron at the temperature of — 253° is actually greater 
than that at - 191° (liquid air), a turning point on the curve 
occurring just below — 200°. Several readings were taken of the 
resistance of the iron spiral when immersed in liquid hydrogen, 
and the readings in liquid air were consistent with my previous re- 
sults. But the observations lack confirmation, and Iam induced 
to publish them owing to the small chance of getting any more 
liquid hydrogen until next year. E. PHILIP HARRISON. 
University College, London, July 31. 
Retention of Leaves by Deciduous Trees. 
I HAVE read with much interest the various communications 
in NATURE on this subject, as the phenomenon was the subject 
of much conjecture to me last winter in Northumberland. In 
one particular instance which I had constant opportunity of 
observing, the cause of the retention of the leaves could hardly 
have been “ protection,” as the beech hedge in question was in 
avery exposed, though by no means an elevated, situation. 
The hedge was a high one, probably 12 or 15 feet high, and 
formed a protection to the garden to the south or south-east of 
it, and in spite of the severe winds to which it was exposed it 
retained its leaves long after those of the beech trees of the 
neighbourhood had fallen. 
Iam inclined to think that it is much more probable that the 
frost theory brought forward by ‘‘ P. T.” in NaTuRE of MayJ15 
is the true solution of the phenomenon than that the retention 
is a ‘* protective device.” 
It would be interesting to know whether ‘‘P. T.” or any 
other readers of NATURE can produce any further proof of early 
frosts causing the premature drying up of the leaves in the case 
of beech hedges and young small trees. If, as ‘‘ P. T.” sug- 
gests, the early freezing prevents the formation of the abscission 
layer of cork at the base of the petiole, it should also cause the 
leaves of hedges and small trees to display their autumn tints, 
or at least to show signs of drying up earlier than the leaves of 
the larger trees. 
If this can be shown to be generally the case where the leaves 
are retained, I think ‘‘P. T.’s” theory would be considerably 
strengthened. A. BaGe 
Henzada, July 1. 
Campanulate Foxgloves. 
In the issue of NATURE for July 24 (p. 306) is a paragraph 
which is somewhat misleading. It is distinctly stated therein 
that ‘‘ the terminal flower of each inflorescence was not a fox: 
glove blossom, but a Canterbury bell (Campanula),” and again, 
**the combination of two flowers other than the foxglove and 
Campanula, if it occurs, would, however, be worth recording.” 
There is no telling what hybridisers may do in the future, but 
it is quite certain they have not yet succeeded in crossing the 
foxglove with a Campanula, nor does it seem likely they will 
ever accomplish such a feat. Bigeneric hybrids (if they are 
really bigeneric) are not uncommon nowadays, but the union is 
always between nearly allied genera, not between groups so 
widely different one from the other as the foxglove and the 
Canterbury bell. The confluence of several of the uppermost 
flowers of the foxglove into a large cup-shaped blossom is not 
uncommon. Indeed, the peculiarity is so far ‘‘ fixed” that 
a large percentage of the seeds from this form may now be 
relied on to ‘come true.” Is this a case of the inheritance of 
an acquired character ? 
The synanthic condition of the foxglove flowers is mentioned 
in my ‘‘ Vegetable Teratology,” p. 40, or p. 59 of the German 
editions, and has repeatedly been recorded, but I am not aware 
that the cause of the deviation has been ascertained. 
MAXWELL T. MASTERS. 
Forestry. 
In my paper on forestry which appeared in NATURE of July 
17 (p. 283) I was wrong in stating that czez//efes means ‘* pro- 
duction of all kinds from baskets and fishing rods to sponges 
NO. 1710, VOL. 66] 
NATURE 
[Aucust 7, 1902 
and caviare.” The term means articles of forest produce, 
collected and utilised, though not specially made the object of 
the working of the forest. 
Fruits and seeds, grasses, flowers, bark, medicinal products, 
and so on, all belong to czezJ//efes. 
This correction is due to Mr. J. S. Gamble, F.R.S., who 
wrote the article in the Royal Scottish Arboricultural Society 
Proceedings, which I noticed in the paper referred to. 
Coopers Hill, Englefield Green, Surrey. W. R. FISHER. 
THE FORTHCOMING MEETING OF THE 
BRITISH ASSOCIATION AT BELFAST. 
SECTIONAL ARRANGEMENTS. 
HOUGH several of the sections of the British 
Association have not completed their programmes, 
it is possible to make a preliminary statement of some of 
the subjects to be brought before the Belfast meeting. 
Up to the time of going to press, the following particu- 
lars of sectional arrangements have reached us. 
In Section A (Physics) there is to be a department in 
astronomy and cosmical physics, to be presided over by 
Prof. Schuster. To this department papers on the work 
on Eros, on the Moon and on Nova Persei will be pre- 
sented, and some discussion on points connected with 
the nebular theory will, it is hoped, take place. Photo- 
graphs from Yerkes Observatory will probably be 
shown, and several seismological communications will 
be made. In the section itself, Lord Rayleigh will pro- 
bably raise the question of the conservation of weight in 
chemical reactions; Prof. Trouton will describe his 
experiments to detect the rotation of the ether with the 
earth, and Dr. Larmor will have something to say on the 
temperature of radiant energy. Belfast will be repre- 
sented in the programme, Profs. Everett, Morton and 
Dixon having several communications to make. 
The presidential address in Section C (Geology), by 
General C. A. McMahon, F.R.S., will deal with the 
general principles of rock metamorphism. Among the 
papers received or promised for the section are the 
following :—(1) “The Geology of the District around 
Belfast, including the Mourne Mountains” ; (2) lecture 
on “The Structure of Ireland,” by Prof. Grenville A. J. 
Cole; on “ The Viscous Fusion of Rock-forming Minerals,” 
by Prof. J. Joly, F.R.S. ; ‘List of Minerals known to 
occur in Ireland,” by Mr. H. J. Seymour ; note on “‘ The 
Scenery of Ceylon,” by Mr. A. K. Coomaraswamy ; on 
“A Lower Carboniferous Fish-fauna from Victoria, 
Australia,’ by Dr. A. Smith Woodward, F.R.S.; on 
“The Graptolites of the Belfast District,” by Mr. R. 
Clark; on “The Valleys at the Head of the Hardanger 
Fjord, Norway,” by Mr. H. W. Monckton; on “The 
Marine Fauna of the Boulder Clay,” by Mr. Joseph 
Wright; on “The Original Form of Sedimentary 
Deposits,” by Rev. J. F. Blake; on “A Stage in the 
Evolution of the Brittle Stars,” by Prof. W. J. Sollas, 
F.R.S.; on “The Fishes of the Lower Devonian 
‘Roofing Slate’ of Gemiinden, Germany,” by Dr. R. H. 
Traquair, F.R.S. 
Prof. Howes is president of Section D (Zoology) 
this year, and it is believed that he will devote his address 
to a general consideration of the importance of the 
morphological method in zoology. As regards the sub- 
sequent work of the section, several papers of a morpho- 
logical and more or less technical character have already 
been promised. The president will show, on behalf of 
Dr. Hill, an interesting series of photographs of seg- 
menting eggs and other early stages in the development 
of Dasyurus. Prof. Johnson Symington will read a 
paper on the “‘Cetacean Larynx.” Prof. MacBride will 
describe the development of Echinus, and Mr. Bles, 
whose exhibit of living larvae of Xenopus (Dactylethra) 
excited so much interest at the Royal Society’s soirée 
