710 REPORT — 1901. 



Geograjihy of the. Air. 



With regard to Meteorology, the distribution of temperature and pressure 

 over the British Islands for the year and for the separate months have been 

 worked out by the experienced hand of Dr. Buchan and published both in 

 separate memoirs and in the ' Meteorological Atlas,' edited by Dr. Buchan 

 and Dr. Herbertson. But such observations as the degree of cloud or of 

 sunshine can as yet be treated only in a superficial and generalised way for 

 want of data. Perhaps the most important and certainly the most difficult of 

 all the atmospheric conditions to discuss fully is precipitation. It depends on so 

 many varying conditions, such as the form and exposure of the land, the altitude 

 above sea-level, the direction and force of the wind, the relative frequency of 

 thunderstorms, the distance from the sea, the direction of the average paths of 

 cyclonic storms, &c., that far more numerous and more long-continued observa- 

 tions are required to establish the normal condition of the country than in the 

 case of either temperature or pressure. When we reflect that the whole water- 

 supply of the country depends directly on rainfall, and when we remember that 

 the value of water-power made available by differences of level promises to be 

 oreater in the future than it has been in the past, we can see that a study of 

 rainfall in conjunction with configuration may prove as valuable for the localisa- 

 tion of the manufacturing centres of the future as the geological survey was for 

 those of the present. 



Thanks to the remarkable foresight and the untiring exertions of the late 

 Mr. Symons, the volunteer rainfall observers of this country have been encouraged 

 to organise their efforts, and by working on a common plan have accumulated 

 within the last forty years a mass of observations unrivalled for number and com- 

 pleteness in any other land. But as yet the difficulties in the way of constructing 

 a map of normal rainfall on an adequate scale have not been overcome, and much 

 experimental work will probably be necessary before it can be accomplished. To 

 this task it is my ambition to devote myself I may be permitted to state that 

 Scotland is far "behind England or Wales in the number of rainfall stations per 

 square mile. Thus there is, roughly, one rain-observing station for every 20 

 square miles of England, one for every .'>0 square miles of Wales, but only one 

 for every fi7 square miles of Scotland, and one for every 170 square miles of 

 Ireland. 



Rainfall observations only tell the amount of available water ; the con- 

 figuration of the stream-beds must be considered in determining water-power. 

 The only country I know where the horse-power of the rivers has been measured 

 and mapped is Finland, but of course individual rivers, such as the Mississippi, 

 Ehine, Seine, and Thames, have been thoroughly studied. Before many decades 

 have passed it will be a necessary element in the surveys of all countries, though 

 at present the available data are few and scattered. 



Population Maps. 



In considering human geography we come to the most interesting and least 

 occupied field of research. Until Mr. Bosse constructed his beautiful maps of the 

 density of population of Scotland and England we had absolutely no carto- 

 graphical representation of the true distribution of people over the laud. To map 

 population by counties gives a very poor idea of the truth, for in such counties as 

 Yorkshire or Perthshire there are large areas entirely without inhabitants, and 

 small areas where the population is very dense. Mr. Bosse's maps were made on 

 the principle of leaving blank all the land on which there were no dwelling-houses, 

 and so obtaining a close approximation to the true density of population of the 

 inhabited area. For Scotland his map shows at once that it is a function of 

 configuration. It shows the densely peopled lowland plain, the less densely 

 peopled coast-strip surrounding the country, and the least densely peopled valleys 

 running inland into the great uninhabited areas. The population map of England, 

 on the other hand, shows an absolutely startling relation to the geological structure, 



