62 iiEPORT — 1900. 



If a meteorologist knows the distribution of barometric pressure over 

 Western Europe, he can then at once state what the weather is in each 

 part of the countries for which he has this information, and he can de- 

 hicribe the weather in fuhiess of detail just according to the accuracy and 

 abundance of the barometric readings supplied to him. This valuable 

 practical result is a direct consequence of the scientific study of the rela- 

 tions of barometer, temperature, and wind as observed over the whole 

 world and interpreted in accordance with physical laws. 



Now this is not forecasting, but only the description of the weather at 

 the time the barometric readings were taken. But it necessarily follows 

 that if the forecaster can guess what the distribution of Isarometric pres- 

 sure will be at some future time, he can state what' the weather will be at 

 that time. Hence the whole problem of forecasting resolves itself into 

 foreseeing the arrangement of barometric pressure in the future. The 

 distribution of pressure does not shift arbitrarily, but the areas of high 

 and low pressure existing on any one day change into those of the next 

 by movement over the surface of the earth and by increase or diminution 

 in intensity, in accordance with physical laws. 



The scientific study of the causes of the movements of these areas of 

 high and low pressure, called respectively anticyclones and cyclones, can 

 only be said to be just beginning. Until this great inquiry has made 

 some substantial progress we cannot have a science of forecasting, as we 

 now have a science of climatological meteorology. 



These areas of low and high pressures are not mere surface pheno- 

 mena, but extend upwards through the atmosphere, and their movements 

 are largely determined by the conditions surrounding them in the upper 

 regions of the atmosphere. 



Towards the expenses of publishing the hourly observations of the two 

 Ben Nevis Observatories the Royal Society of London has made a grant 

 of 5001., and a grant to the same amount has been made by the Royal 

 Society of Edinburgh. These societies thus approve of the publication as 

 a necessary preliminary to the scientific study of forecasting. The Ben 

 Nevis Observatories have already largely contributed to the fundamental 

 data of meteorology, and in the future the observations they supply will 

 take a promment place in the development of scientific forecasting. 



Your Committee have the greatest pleasure in adding that at the 

 meeting of the Scottish Meteorological Society in March last J. Mackay 

 Bernard, Esq., of Dunsinnan, intimated a third handsome donation of 

 500^. towards the maintenance of the observatories to the end of next 

 year. Another gentleman, on learning that assistants were urgently 

 required to assist Dr. Buchan and Mr. Omond in the oSice, at once readily 

 and most generously intimated a donation of 300^. to the Council of the 

 Society for the purpose. 



Iladicdion in a Magnetic Field. — JReport of tJi,e Committee, consistiiuj of 

 Professor G. F. FitzGerald {Chairman^., the late Professor T. 

 Peeston (Secretary), Professor A. Schuster, Professor 0. J. 

 Lodge, Professor S. P. Thompson, Dr. Gerald Molloy, and Dr. 

 W. E. Adeney. 



The Committee regret that they are unable to report that any further 

 work ha? been dolie with thfe gfeat spectroscope belorigiilg to the Roy*I 



