244 
NATURE 
[APRIL 29, 1915 


east coast of Scotland, and the possibility of the exist- 
ence of outliers beneath the Glacial drift, is shown 
by the account (p. 131) of the Cretaceous sandstone 
of Leavad, which was recognised by D. Tait in 1906. 
This block, 240 yards in length, is used as a sand- 
quarry, and rests on a green clay which, from its 
foraminifera, G. W. Lee regards as perhaps of 
Pliocene age. This in turn rests on boulder-clay, so 
that, as happens in Ostpreussen (NaTuRE, vol. Ixxxv., 
p- 470), local geology has been distinctly enriched by 
material imported during the Ice age. 
The Geological Survey states that the issue of some 
of its colour-printed maps is delayed by work necessi- 
tated by the war; but it makes its own contribution 
to military needs in a pamphlet on ‘Sources of 
temporary water supply in the south of England and 
neighbouring parts of the Continent’’ (1914, price 
od.). The waters of sand-dunes, alluvium, and river- 
gravels are especially considered, and useful warnings 
are given as to pollution. It is remarked (p. 10) that 
a well sunk in sand or gravel on a chalk hill may 
lose its water if carried down to the surface of the 
porous chalk. 
The proceedings of local societies, especially where 
universities are at hand to provide a stimulus, afford 
valuable supplements to the publications of the official 
surveys. The second part of vol. xv. of the Trans- 
actions of the Geological Society of Glasgow (price 
zs. 6d.) forms an admirable example. All the papers 
record original observations in southern Scotland. 
Prof. J. W. Gregory (p. 174) treats of the red rocks 
of the Isle of Arran, which he regards as including 
Permian desert-beds at Brodick. These terrestrial 
deposits are, he urges, Lower Permian, and the 
appearance of conformity with the Keuper Marls 
above may be deceptive. G. W. Tyrrell (p. 188) 
describes critical sections in spots which he visited at 
Prof. Gregory’s request, and is unable to discover any 
break in the sedimentation. The papers by P. 
Macnair, R. G. Carruthers, and J. E. Richey on the 
lower beds of the Carboniferous Limestone Series 
will do much to help workers in other districts, such 
as the north of Ireland. GAASIaG: 

EXPERIMENTAL BOTANY AT. TRINITY 
COLLEGE, DUBLIN. 
[|X “Notes from the Botanical School of Trinity 
College, Dublin,” No. 5, vol. ii., 1915, Prof. 
H. H. Dixon gives experimental proof that morbid 
changes spread through plants from branches killed 
by heat. If a portion of a branch be killed by heat 
and the substances dissolved as the result of the heat- 
ing be washed away, morbid changes only take place 
after some fourteen days. In cases where no steps 
are taken to remove the poisonous substances liberated 
by the heating, the branches above the heated portion 
show morbid changes in the course of five days. 
It is clear from the experiments that with the killing 
of the cells by heat, substances are liberated into the 
sap which contaminate the water supply to the living 
tissues above, and that the morbid changes are not 
due to the cutting off of the supply of water. 
In a further paper in the same number of the 
‘*Notes’’ Prof. Dixon gives the result of his investiga- 
tions into the nature of the changes which are produced 
in the sap by the heating of the branches. Sap was ex- 
tracted by means of acentrifuge from pieces of branches, 
and was examined both fresh and after steaming for 
the acidity, colour, presence of oxydases and quantity of 
dissolved substances. The steamed sap showed marked 
acidity, a much higher percentage of dissolved sub- 
stance—indicated by the depression of the freezing 
point—and a development of colour, any oxydase pre- 
NO@r2374;, VOL. 951 

sent being, of course, destroyed. The presence of 
poisonous properties was proved by placing leaves of 
Elodea canadensis in the steamed .and in fresh sap, 
when it was noticed that lethal effects were produced 
quickly by the steamed sap, and that the leaves would 
not recover when placed in water. 
In a paper on the tensile strength of sap, Prof. 
Dixon records tensions of about 207 atmospheres and 
132 atmospheres in a tube of sap collected from a 
branch of Ilex aquifolium. The former of these is 
probably the highest yet :ecorded for the cohesion of 
any liquid. The tensile strength of the sap of trees, 
like that of water, is considerable, but it is probably 
somewhat more stable under tension than pure water. 
Prof. Dixon and Miss Marshall have also examined the 
elements of the wood of trees in relation to the ascent 
of sap, and find no evidence to support Janse’s hypo- 
thesis as to the intervention of the living cells in the 
ascent of sap in stems. 
Mr. W. R. G. Atkins publishes a series of careful 
papers on oxydases and their inhibitors in plant tissues, 
and his work confirms that of Keeble, Armstrong, and 
Jones. The distribution of oxydases in the flowers of 
Iris has been particularly studied; when they are kept 
in darkness, the quantity of active peroxydases in- 
creases. In the Pogoniris group an active peroxydase 
is absent. The localisation of oxydases and catalases 
in some marine Algz has also engaged the attention 
of the author. 

ENGINEERING, EDUCATION, AND 
RESEARCH. 
ESEARCH.—Research for the solution of new 
problems is of great importance, but it is not a 
task for young and immature students. Many so-called 
researches, in which well-understood methods are 
applied to materials or subjects not themselves impor- 
tant, scarcely deserve the name. They amount to 
little more than class exercises. Most scientific socie- 
ties receive papers in which a much over-elaborated 
description is given of known proceedings and pre- 
cautions, in which the new results are of limited value 
without establishing any general law. But the value 
of real research, based on a clear formulation of a 
definite unsolved problem, cannot be overestimated. 
Unfortunately, in engineering, the solution of un- 
solved but important problems is generally both diffi- 
cult and expensive. Much, no doubt, is done by manu- 
facturers who have a financial interest in the work. 
But their researches are, in general, not fully pub- 
lished. It is of great interest to the public at large 
and to other engineers that a scientific institution 
like this feels it part of its duty to advance knowledge 
by research, and is able to devote a fraction of its 
income for such researches as are beyond the means 
of private engineers. In most cases, a research com- 
mittee of this institution begins by an investigation 
of what has been done befcre, and the summary of 
previous investigations which the institution publishes 
is not only a safeguard against mere repetition of 
experiment, but is valuable in itself. Prof. Martens, 
the director of the great State laboratory at Gross- 
lichterfelde, has said that in four cases out of five 
when a manufacturer brings him a problem, it is found 
that it has already been solved somewhere by some- 
body. 
The War and Engineering.—We meet in circum- 
stances not foreseen a year ago. A war of unpre- 
cedented magnitude, extending over a vast area, has 
broken on us with the suddenness and fury of a 
tropical storm. We are already proud of the courage 
1 From the presidential address delivered to the Institution of Mechanical 
Engineers on April 16 by Dr. W. Cawthorne Unwin, F.R.S 

