415 
of Edinburgh , Session 1868-69. 
raises tlie temperature of the air as it approaches this island, and, 
by warming the sea, raises watery vapour to moisten the lower 
stratum of air. Hence the May east wind arrives both warmer and 
less dry. It is now therefore for the most part much less unpleasant 
to the feeling than in March and April. Towards evening, how- 
ever, as the sun’s rays fail in force, the air, cooling down, parts with 
moisture to form mist, which creeps up our Firth, spreads over the 
neighbouring land, prevails all night, and lasts into the next fore- 
noon, till it vanishes under the renewal of the heat of the air from 
the sun’s rays. During the misty time the uncomfortable impres- 
sion on the human frame is renewed in spite of the air being now 
moist, partly because the temperature is lowered, partly because 
mist — being a form of water in the liquid state — is a more powerful 
conductor of heat from the body than the same water dissolved in 
the air as gas. Accordingly, as the mist is dispelled with the 
advance of day, the sense of discomfort vanishes, because the air 
is warmer, and is loaded merely with perfectly dissolved aeriform 
moisture. It is remarkable, he adds, that the unpleasant influence 
of these east winds on man do not then correspond with their 
influence on vegetation. In March and April the cold, dry east 
winds wither up and destroy leaves prematurely unfolded. Later in 
the season an east wind, equally cold, but loaded with moisture, 
does them no harm, because it loses its parching, withering property. 
This important difference every careful observer must have noticed. 
In the case of the animal frame, however, the mere cold of an 
easterly mist is adequate to cause discomfort, and injury to the 
health. Thus Hutton maintains that all the disagreeableness and 
injury occasioned by our east winds, both in spring and in early 
summer, may be adequately explained by reference simply to their 
condition in point of temperature and humidity, without our 
requiring to take account of any other agency, hidden and mysterious 
in its nature and operation. I have dwelt a little on these simple, 
yet profound, views of Hutton, because, like other inquiries of 
his, they have been too much lost sight of in our time, and they 
may help to clear up and satisfy many minds which have been 
hitherto much obfuscated and discontent in respect of the present 
matter. 
Hutton appears never to have had an opportunity of studying 
3 ii 
VOL. VI. 
