Handbook to the health resorts of Switzerland : containing full information for the physician, the healthseeker and the traveller as to all the baths, climatic stations, springs and watering places of Switzerland / by H. Loetscher.

Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Handbook to the health resorts of Switzerland : containing full information for the physician, the healthseeker and the traveller as to all the baths, climatic stations, springs and watering places of Switzerland / by H. Loetscher. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    air near the* woods. It is easy to see from the foregoing how deleterious would be the effect on the climate—not to speak of other evil results—of destroying large woods ; for in the warm months, especially, there would be those excessive differences in temperature between day and night that are experienced in the desert of Sahara. The climate of a country, as has been shown above, is determined both by the temperature and the humidity of the air. A moist atmosphere obviates extreme heat and cold— a fact which we noted when speaking of the lake climate. Aqueous vapour has the property of very largely absorbing the rays of heat, while perfectly dry air allows the sun to penetrate with almost all its power to the surface of the earth. Aqueous vapour, on the other hand, acts as a cover- ing during the night and protects the ground from excessive radiation and cooling. The woods are the chief cause ot moisture; the air of the woods, and especially of dense woods, is more humid than the air of the open country. This is particularly the case where the trees are young, for the numerous apertures in old timber allow the wind to en- ter. The greatest difference is observable after heavy rain, when for a long time the air among the young trees re- mains saturated, or very nearly so, a circumstance which as regards hygiene is worthy of all attention. A large extent of young woodland makes the climate milder and softer. Especially is this noticeable in the hot summer months and in high mountain places. The woods conduce much more in summer than in spring, autumn and winter to a preci- pitation of moisture, and keep the country well-watered. Besides, the air in the woods has this great advantage, it is free from the noxious gases, fumes and smells which arise in towns from impurities of the soil or the presence of ma- nufactories; neither is it polluted by the smoke and soot issuing from thousands of chimneys in busy places ; lastly, it is free from the dust of the streets which so often annoys the dwellers in towns and injuriusly affects their health. Closely, and perhaps causatively, connected with the humidity of the air is that change in the oxygen of the atmosphere known as ozone-making, a process important alike in the economy of nature and of the human frame. Moist air in the mass is richer in ozone than dry air, and the ozone increases with the humidity. It has been observed that rapid evaporation of water and strong winds generate a great deal of ozone, which is undoubtedly present in largest quantities in rainy, stormy weather. There is least during the preva- lence of mist, cloud, frost, or thick yellow fog. wherefore foggy weather is, as a rule, to lie regarded as unhealthy. But in addition to moisture and high winds there is another source of ozone in the aroma which, under the influence ot the sun’s rays, is exhaled by such trees and plants as the
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