Distribution of Frequency of the Barometric Height. 491 



lines on page 121 from "The extent" to " 0*001, " and substitute 

 " The capacity of window glass is but little affected by variations of 

 frequency at ordinary temperatures." The statement as it stands is 

 hardly likely to mislead as it is obviously incorrect ; it is unlikely 

 that capacity would increase with frequency. 



" On the Distribution of Frequency (Variation and Correlation) 

 of the Barometric Height at diverse Stations." By Karl 

 PEARSON, M.A., F.R.S., University College, London, and 

 Miss Alice Lee, Bedford College. Received June 15, — 

 Read June 17, 1897. 



(Abstract.) 



1. Although this paper contains the results of a very large amount 

 of arithmetical work, which has been in progress during the last 

 two or three years, it is not intended in the first place as a contri- 

 bution to the meteorology of the British Isles. It is especially 

 intended as an illustration of method. The authors believe that 

 hitherto no exact theory of variation or of correlation has been applied 

 to meteorological observations, and they have endeavoured to indi- 

 cate that fruitful results may be obtained from such a theory when 

 applied to one branch at least of meteorology, namely, barometric 

 frequency. They wished to deal with a fairly extended area with 

 an easily accessible material, and this was found in the Meteorological 

 Observations at Stations of the Second Order for the British Isles. The 

 " telegraph " stations would have provided better material, but it was 

 far less accessible. The authors have accordingly only dealt with 

 three telegraph stations. The main body of their data was drawn 

 from twenty stations of the second order, four of which are in 

 Ireland, and the remainder distributed round the coast of England, 

 Wales, and Scotland, as indicated on a chart accompanying the 

 memoir. 



2. Their first object was to determine the nature of the barometric 

 frequency distribution. By means of tables and plates it is shown 

 that it can be described with a very high degree of accuracy by 

 the use of a generalised frequency curve of the type-^ 



/ x\P 



a type which has been fully discussed in a previous memoir on skew 

 variation. 



A standard frequency curve for the British Isles having been 

 selected, it is shown that the frequency distribution varies con- 



