CLIMATES OP GREAT MALVERN AND LONDON. 61 



round— whether the sub-soil is rocky, chalky, clay, or otherwise, — 

 whether the contiguous localities are well or ill drained, — and whe- 

 ther, with reference to the country around, it lies rather high or 

 low. The conditions of the surface of the district, and its neigh- 

 bourhood, should also be stated ; whether extensive tracts of mea- 

 dow land, or arable land, prevail, — much or little wood, water, &c. 

 With such additional information, meteorological observations would 

 be rendered trebly valuable. 



The atmosphere often varies very much in transparency. Some- 

 times it is loaded with a light haze or mist, at others it is perfectly 

 clear, so that distant objects appear nearer; sometimes the haze or 

 mist is very great, and yet the air, as shewn by the hygrometer, is 

 very dry ; indeed, with our driest winds (N. E.), the haze is gene- 

 rally most prevalent : it must, therefore, at such times, be very dif- 

 ferent from any form of vapour. A hazy state of the atmosphere, 

 such as that just noticed, is called, by the common people, a blight. 

 Whether it exerts any such effect upon the human frame, is a ques- 

 tion to be determined ; at all events, it should be clearly distin- 

 guished, by the meteorologist, from that thick and muddy appear- 

 ance which the air often assumes when its temperature is no greater 

 than the dew point, and which arises from the commencing precipi- 

 tation of vapour. 



The more obvious effects resulting from the precipitation of va- 

 pour, diffused through the air by the heat of the sun, are rain, fogs„ 

 and dew. 



It is well known that aqueous vapour facilitates the vaporising 

 force of many substances, becoming, as it were, a carrying agent. — 

 A theory of meteoric stones has been founded on the supposition 

 that the earthy and metallic matter found in them had been raised 

 in vapour from similar matter upon the earth's surface, which, 

 though extremely attenuated and dilute at first, gradually accumu- 

 lated, and, by some natural operation in the upper regions of the 

 atmosphere, became condensed, forming those extraordinary masses 

 of matter which occasionally fall to us from above. However this 

 may be, we cannot doubt that many noxious exhalations are carried 

 up by the aqueous vapours arising from the ground during the day, 

 but which are, in their ascent, so extremely attenuated and dilute 



