NovEMBER 5, 1903] 
- States, and, indeed, wherever meteorology is studied. The 
| other subjects treated in these papers include :— 
(1) The changes in the hourly variation of the barometer 
in fine and in cloudy weather at Ben Nevis, Fort William, 
and several other stations. 
(2) The general meteorological conditions on Ben Nevis 
in clear and in foggy weather. 
(3) Atmospheric dust on Ben Nevis. 
(4) The pumping effect on a barometer of strong winds. 
(5) The difference in the direction of the wind at Ben 
Nevis from that at sea-level. 
(6) The change of temperature with height in anti- 
cyclones. 
(7) The diurnal ranges of the Ben Nevis and Fort William 
barometers when both are reduced to sea-level by the usual 
tables. 
(8) The diurnal range of the variability of temperature 
from day to day at Ben Nevis and some other places. 
(9) The meteorological conditions at Ben Nevis during 
the severe frost of January and February, 1895. 
(10) The relation of wind direction to temperature and 
to rainfall at Ben Nevis. 
The establishment of the Ben Nevis Observatories has 
provided meteorological data of a character unique in this 
country, and, indeed, in the world, owing to the position 
of Ben Nevis as a high-level station placed right in one 
of the storm-tracks of the Atlantic. But it has also led to 
investigations which could not otherwise have been carried 
out, for no increase in the amount or quality of low-level 
observations would have supplied the necessary data, and 
the high-level records got from kites or balloons are too 
fragmentary for the purpose. 
The observatories were built with money subscribed by 
the public, and up to this time have been supported by 
subscriptions, aided by an annual payment of rool. for the 
Ben Nevis Observatory and 2501. for the Fort William 
Observatory from the Parliamentary grant of 15,3001. given 
annually for meteorological purposes. What their future 
position may be depends on the recommendations of the 
Parliamentary, Committee of Inquiry into the administra- 
tion of this grant now sitting, but whether Parliament 
gives the money necessary to carry them on, or whether 
they are closed and abandoned, as they assuredly will be 
if not taken over by the State, the work done at and in 
connection with these observatories is a record of investi- 
gation which will be growingly studied by meteorologists. 
Edinburgh, October 17. R. T. Omonp. 
No one is more conscious of the shortcomings and 
omissions of the address than its author. One correction 
I should like to make here. The joint editors of the 
Meteorologische Zeitschrift are Dr. Hann and Dr. Hell- 
mann; Dr. Pernter is associated with the journal as 
““ Herausgeber.” 
I cannot fail to be aware that, with perfect propriety, I 
might have devoted a large part, or even the whole, of the 
address to the obligations of meteorology to private enter- 
prise in this country. In that case it would have been a 
different, perhaps a better, address, but I will ask your 
readers to believe that any omissions of that kind which 
they detect and regret were not due to a desire to belittle 
anything except the address itself. 
In one sentence I did explicitly refer to Edinburgh and 
Ben Nevis. I cannot altogether emulate the achievement 
of Mr. Puff, who managed to extract so much meaning from 
a shake of Lord Burleigh’s head, but I should like to say 
that if Sir Arthur Mitchell had used an appropriate magni- 
fying power, and had got it properly focused upon that 
sentence, he would have read the following opinion which 
the mention of Ben Nevis always suggests to my mind, 
“that if means were found for endowing a chair of 
meteorology in the University of Edinburgh, and one of the 
distinguished Scottish meteorologists, whose names re- 
quire no announcement from the chair to make them known 
to the British Association and far beyond, were appointed 
thereto, a most important and productive step would be 
taken towards the solution of the many problems connected 
with the great Scottish work of the Ben Nevis Observ- 
atories, the twenty-first annual report of which Dr. Buchan 
will present to the Association.” W. N. SHAW. 
October 21. 
NO. 1775, VOL. 69] 
‘NATURE 7 
Weather Changes and the Appearance of Scum on 
Ponds. 
Ir any of your readers could explain an interesting 
natural phenomenon constantly occurring here we should 
be very grateful. It is simply that, invariably before any 
decided change of weather, there comes up a scum on the 
surface of the pool or small lake which skirts our south 
and east lawns—part of the pleasure grounds surrounding 
the mansion. Sometimes it looks like soapy water, but at 
other times it is black, and makes the breasts of our swans 
as black as ink just above the water-line. Then the scum 
will suddenly disappear, and the swans’ breasts become 
white again. Our geological formation is the junction of 
the Upper Greensand and the Lower Chalk. The bottom 
of our lake is chalk; it is fed by springs, and the stream 
formed by its overflow runs finally into the Thames. It is 
shallow, and is surrounded by large trees. There are at 
present eight swans on it, also many moorhens and wild 
duck, and quantities of fish, which attract herons; king- 
fishers live in the bank, which is very high on the far side. 
There is also an island with large trees and a dense under- 
growth. PLATANUS ORIENTALIS. 
Aston Rowant, Oxon. 
With reference to the letter of ‘* Platanus orientalis,” 
it seems to me that a possible explanation of the appear- 
ance of dirty scum on the surface of the pond before any 
decided change of weather may be that a sudden change 
of barometric pressure may accelerate the flow of springs 
rising through the chalk of the floor of the pond. This 
would carry up to the surface of the water some of the fine 
mud which had rested on the chalk, or even lodged in 
crevices within it. When the flow of the springs diminished 
or ceased, the sediment would naturally subside once more. 
It would be interesting to keep an exact record of the 
appearance of the scum and of the variations of atmospheric 
temperature, pressure, and the rainfall by automatic record- 
ing instruments. 
Without knowing the local conditions it would be im- 
possible to speak definitely as to the sufficiency of this 
explanation. 
Another that occurs to me is that, if the sediment at the 
bottom of the pond is of a flocculent character, its move- 
ments may be due to the same cause as those of the pre- 
cipitate in a ‘‘ storm-glass,’’ whatever that cause may be; 
but in that case the appearance would probably be limited 
to dead calm weather. 
It is possible that the scum may be organic, and 
it would be desirable to have it examined microscopically 
by a student of limno-plankton. 
HuGu Rosert MILL. 
Cranial Casts. 
In the number of Nature which arrived here to-day there 
is a report of the interesting presidential address delivered 
by Prof. Symington in Section H at the British Association’s 
recent meeting. In this report there are several statements 
which are likely to prove misleading to those who are not 
familiar with the literature relating to brain-casts. The 
reader might imagine (see p. 540) that this was an entirely 
new branch of research suggested by Dr. Forsyth Major’s 
work on the subfossil Lemuroids (1898) and only fully 
exploited by Prof. Schwalbe in 1902. This, of course, can- 
not be the meaning which Prof. Symington intended to 
convey, because he is quite familiar with the scores of 
cranial casts made in such profusion by Prof. Gervais in 
the years 1867-1871, and by a long line of anatomists and 
paleontologists both before and since that time, and with 
the valuable contributions to knowledge which have re- 
sulted from this fertile branch of study; in fact, Prof. 
Symington happened to visit the work-room in the Royal 
College of Surgeons in 1901 when I was examining and 
describing the considerable collection of such casts (repre- 
senting more than one hundred genera) which have been 
brought together by the late Sir William Flower and the 
present conservator, Prof. C. Stewart. (And, with refer- 
ence to Prof. Symington’s remarks on curators, I. may 
mention that no one more fully recognises the value of 
cranial casts than the present conservator of the Royal 
College of Surgeons’ Museum.) 
