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ON METEOROLOGY: ITS PRESENT PROGRESS AND 

 FUTURE PROSPECTS 



By BALFOUE STEWART, L.L.D., F.R.S., Director of the Kew Observatory. 



Meteorology, or tlie Phenomena of the Earth's Atmosphere, may be 

 studied from two points of view, which are in reality quite distinct from one 

 another. 



"We may in the first place desire to investigate those atmospherical con- 

 ditions which render certain places on the earth's surface suitable for a certain 

 class of organised beings. Thus for instance, we may have a cold climate or 

 a hot one, a dry climate or a moist one, a climate that varies very little from 

 day to night — from summer to winter, or one that varies in these respects a 

 great deal. 



Now some of these climates may be suitable for a certain class of persons, 

 but not for others ; and some of them may be favourable towards the growth 

 of a certain class of plants, while other vaiieties may not thrive therein. Indeed, 

 it is universally acknowledged that animals and plants are influenced to a very 

 large extent by considerations of climate. 



Nevertheless, I am not aware that physiologists have ever set themselves 

 seriously and systematically to investigate the precise relations which [subsist 

 between climate and health. As an example of this we may take the element 

 of moisture. It has been the custom to express the state of the au* with regard 

 to this element by means of the proportion subsisting between the amount of 

 vapour which the au- at any moment contains, and that amount which it is caisable 

 of containing while it remains at its present temperature. Thus, if air at 60° 

 Fahrenheit contained half as much vapour as it was callable of holding at this 

 temjjerature, we should represent the relative saturation by ^ ; if it only con- 

 tained one-third of the whole amount we should call the saturation ^ ; while if 

 it contained all the vapour it was caj>able of holding at that temperature we 

 should represent the saturation by unity, which thus denotes complete saturation. 



But has complete saturation at all temperatiues the same effect upon 

 organized beings? thus, for instance, when the temperature is very high will 

 not its effect be greater than when there is only a moderate lieat ? We may 

 ask the question, but no answer has yet been fuinished, nor as far as I 

 know has any joint action been taken by meteorologists and physiologists with 

 the view of investigating this important question. 



But important as a knowledge of the effect of climate upon health un- 

 doubtedly is it does not yet constitute the main problem of meteorology. To 



