TRANSACTIONS OF SECTION A. 481 
type occurring in the British Isles, maps were prepared on which the areas 
receiving a rainfall exceeding half an inch, one inch, two inches, &c., were laid 
down from the daily observations of observers reporting to ‘ British Rainfall.’ The 
path of the associated cyclone was inserted from the Monthly Summary o’ the 
‘ Weekly Weather Report.’ ‘ Z ; 
In nine of these cases it was found that, irrespective of the direction in which 
the cyclone travelled, the area of heavy rainfall (exceeding one inch in twenty-four 
hours) lay almost entirely on the left of the path, and that the wet area was in 
advance of the centre. The tenth case was one of nearly symmetrical distribution 
about the path. 
The relationship cannot be accidental, and suggests both theoretical and 
practical considerations of great interest, according with the views of the circula- 
tion of air in a cyclone recently put forward by Dr. W. N. Shaw, and suggesting 
a more definite basis for forecasting heavy rains. 
It must of course be remembered that all cyclones of equal depth of depression 
and rate of progressive movement are not rain-bearing to the same extent. The 
cyclone of February 27, 1903, which produced most disastrous damage by wind, 
brought little rain. The somewhat similar depression of September 10, 1903, 
remembered as occurring during the meeting of the British Association at 
Southport, brought a widespread rainfall, but no very serious wind. 
The remarkable rainfall of June 13, 14, and 15, 1903, between Cambridge 
and the Thames Valley, when one inch or more per day fell on three consecutive 
days, was associated with a depression which followed an elliptical path with the 
wettest area always on its left, a very unusual course, producing an unprecedented 
rainfall in a comparatively dry area. 
5, The Application to Meteorology of the Theory of Correlation. 
Ly Miss F. E. Cave. 
During the last few years the methods of the theory of correlation have been 
applied to the records of barometric observations taken during the years 1879 to 
1898 at various stations on each side of the Atlantic. The correlations between 
Wilmington (North Carolina) and Halifax (Nova Scotia), two stations about a 
thousand miles apart, have been calculated, different intervals being allowed 
between the corresponding observations. The magnitude of the correlation varies 
with the interval, being greatest when Halifax is taken one day later than 
Wilmington. This seems to indicate a drift of barometric conditions northwards 
and eastwards ; and the satisfactory results obtained in this case encourage the writer 
to hope that the application of similar methods to readings taken at stations on 
opposite sides -of the Atlantic, a longer interval being allowed, may lead to the 
discovery of correlations sufficiently large to be of use in the practical work of 
prediction. 
It has also been found that the correlation between simultaneous barometric 
heights at two stations lying north and south of each other, at a sufficient distance 
apart, may be a negative quantity of considerable magnitude, and that the correla- 
tion varies with the distance in a manner which deserves further investigation. 
The application to meteorology of the theory of correlation may be of import- 
ance, both for prediction and also in leading up to fuller knowledge of the laws of 
the atmosphere, by supplying more detailed information than is otherwise obtain- 
able as to the connection between different stations as regards either the barometric 
heights there or any other of the quantities with which meteorology deals, 
6. The Development of the Aeroplane. By Major B. Bapren-Powstt. 
The day is undoubtedly drawing near when we shall be utilising the highway of 
the air for travel, and it is now becoming an interesting question as to what form 
the motor car of the skies is to take, , ‘ 
1904, It 
