Marcu 14, 1912] 
NAT ORE. 
272 
rere) 
is somehow supplied, cause water to pass into a 
solution; for on the side of the solution it holds less 
water than on the side of the water unless the solu- 
tion is raised in pressure so as to bring the concentra- 
tion of water in the ether to be the same throughout. 
Frep. T. TRouton. 
University College, London. 
The Weather of 1911. 
Ir is probably no exaggeration to say that all 
students of meteorology who have been fortunate 
enough to read Sir Edward Fry’s letter in 
Nature of November 16 have been greatly impressed 
by it, and have awaited with eagerness the discussion 
to which it must inevitably lead. Already, at this 
early stage, they must feel a sense of gratitude to 
the writer of the letter for having enriched the 
science by calling forth the excellent reply from Dr. 
Shaw in the number of November 30. 
Now, as was to be expected, that ultra-violet solar 
radiation has come up for consideration, and Dr. 
Carl Ramsauer, in the issue of December 14, has 
entered a strong plea for recognition of the part 
it did not play in producing rain, in Europe, during 
the summer and fall of 1911, the time seems ripe for 
“the other side of the world” to enter the discussion, 
so that European men of science may take a glance 
“out and beyond their latticed home,” and realise 
that sunshine and meteorological changes are 
phenomena quite commonly witnessed in other 
regions of the earth. 
It is to be understood that nothing in this letter 
is to be considered as the result of a careful study of 
observational data, and, furthermore, that the ideas 
here expressed have been inspired solely by articles 
in Nature, by my personal experience, and by a 
cursory knowledge of meteorological changes gained 
from the weather chart of the Argentine Meteoro- 
logical Office, which shows the daily changes over 
the southern half of South America, a region quite as 
extensive as, if not much greater than, all Europe. 
In his interesting article, Dr. Ramsauer says, 
amongst other things, that he and Prof. Lenard have 
distinguished three actions of ultra-violet light on 
dust-free gases, and that one of these actions 
is the ‘‘formation of condensation nuclei.”’ This, he 
Says, gives us the chief source of nuclei in the earth’s 
atmosphere, which are meteorologically so important ; 
and his final conclusion is:—‘‘Thus the lack of 
nuclei, and the consequent fine weather of the year, 
can be attributed to a much diminished ultra-violet 
radiation of the sun.’ (The italics are mine.) He 
makes no mention as to variable efficiency in different 
parts of a bundle of solar rays, and so his conclusion 
must be taken as uniformly applicable to the entire 
bundle of rays impinging upon the earth. As the 
difference’ of longitude between the two continents 
is only a few hours, it may be assumed that the solar 
rays falling upon Europe and South America con- 
stitute separate parts of a single uniform bundle of 
rays; also, as ultra-violet rays are to be considered 
as the controlling agency in the production of con- 
densation nuclei, they must be assumed to be most 
active, and rainfall therefore most copious, over the 
continent with the midsummer sun. Let us see how 
far his conclusions are justified by facts. 
During the mid-year and later months of torr 
Europe experienced an unprecedented season of heat 
and drought, beneath the unobstructed rays of a high 
sun; Dr. Shaw states that apparently all requisites 
for dense clouds and heavy rains were frequently 
satisfied, and Dr. Ramsauer suggests that the poverty 
NO. 2211, VOL. 89] 
Wee 
mor 
of the intense solar rays in ultra-violet waves was 
responsible for the fact that no precipitation occurred. 
During the same period, July to November, a portion 
of South America equal in extent to Europe, under 
the relatively feeble radiation of a low sun, was treated 
to a superabundance of condensation nuclei, and 
probably to the most excessive drenching ever noted 
in this part of the world. The current conditions, 
with reversed seasons, are really just as interesting. 
| The rains continued here during the summer solstice 
and ended suddenly on January 1; so that, on passing 
through perihelion, although the sun was not far 
from the zenith, and was about five million miles 
nearer than when Europe experienced its extra- 
ordinary weather, sending out proportionately more 
intense ultra-violet and all other kinds of solar rays, the 
sky was clear, and has remained practically so during 
the past two weeks of our midsummer, notwith- 
standing that this is normally the rainy season of the 
year, and conditions are favourable for the develop- 
ment of showers and even general rains; meanwhile 
in Europe, mirabile dictu, the advent of the new year 
has been marked by disastrous floods in many parts. 
Do not these facts constitute another exemplification 
of the saying that ‘‘one-half of the world does not 
know (usually realise) how the other half lives,’ and 
of the further thought that it is extremely difficult 
completely to interpret cosmical processes by means 
of laboratory experiments? 
In the present state of the sciences of meteorology 
and solar physics it is impossible to look upon these 
perfect and abnormal contrasts of the past year in 
the conditions in Europe and South America as 
merely fortuitous occurrences. In seeking for their 
explanation we must inevitably follow Dr. Shaw in 
ascribing the important terrestrial activities to the 
dynamics of the upper air, and amplify his proposition 
slightly by naming the sun as the prime source of all 
the trouble. Is it not possible that with the already 
long period—nearly two years—of almost complete 
quiet on the solar disc, the conditions on the earth 
are approximating to what they would be if the sun 
were not a variable star? With a constant output 
of solar energy would not the atmospheric layer con- 
tained between the isothermal region and the earth’s 
surface act more uniformly, like an engine—the part 
over the summer hemisphere, being heated by the 
most intense radiation during long days, acting as 
steam chest; the part over the winter hemisphere, 
cooling through long nights and feeble solar radiation, 
acting as condenser, while the convective processes of 
the equatorial region serve as the safety-valve through 
which would be brought about an orderly alternation 
of hot and relatively dry summers, and wet but not 
extremely cold winters in both hemispheres? 
It is probable that a complete answer to Sir Edward 
Frv’s question will have to come from some such 
world-wide conception as this rather than from a 
study of meteorological conditions on a particular con- 
tinent. Possibly the pronounced conditions during the 
past year may point out a way for alleviating to some 
extent the disappointment of those investigators who 
seek to establish a well-defined periodicity in tem- 
perature and rainfall variations based upon the vari- 
ability of the sun, as they apparently emphasise 
the necessity of determining exactly the epochs of 
maxima and minima in the sun’s own period, and 
taking account of his position in the ecliptic at such 
times. If a minimum, for instance, coincide with a 
solstice, then an abnormally hot and dry summer in 
one hemisphere, with an abnormally wet and probably 
warm winter in the opposite one, should be con- 
sidered as confirming the sun-spot theory, and not 
as contradicting it, and so the effect may be graduated 
