294 THE POPULAR SCIENCE MONTHLY. 



than in much less cold air which impinges with considerable velocity 

 upon the surface of the body. The effect of motion through the air 

 upon the sensation of warmth and cold at Davos is very striking. Sit- 

 ting perfectly still in the sunshine, the heat in midwinter is sometimes 

 almost unbearable ; on rising and walking about briskly, a delicious 

 feeling of coolness is experienced ; but, on driving in a sledge, the cold 

 soon becomes painful to the unprotected face and hands. 



Such are the conditions prevailing at Davos, and producing the 

 delightful climate of this winter resort. They may be thus briefly 

 summarized : 1. Great elevation above sea-level ; 2. A continuous, and, 

 during winter, permanent covering of snow ; 3. A minimum of watery 

 vapor in the air ; 4. A clear sun ; 5. A clean atmosphere, free from 

 zymotic germs, dust, and fog ; 6. A sheltered position, favorable for 

 receiving both the direct and reflected solar rays. 



I have been thus particular in describing these conditions in order 

 to make clear the capability of the Yellowstone plateau to provide a 

 similar beneficent winter climate for invalids. 



From my own observations, and from inquiries made on the spot, 

 I am of opinion that the Yellowstone National Park possesses, in a 

 high degree, all these essential conditions. In elevation above the sea 

 it surpasses Davos ; the great plateau of the park is between 7,000 and 

 8,000 feet above sea-level, while it is stated that not one of the narrow 

 valleys dips below 6,000 feet. The mountain-ranges, partly surround- 

 ing and partly within the park, rise to heights of from 10,000 to 

 12,000 feet. I should anticipate, therefore, that all the advantages 

 which, as a winter resort for invalids, Davos possesses from its elevated 

 position, would be enjoyed even in a greater degree in the Yellowstone 

 Park. The period of permanent snow is longer, so that invalids could 

 remain there probably until the end of April, whereas the melting of 

 the snow generally compels them to leave Davos early in March, when 

 the climate of the valleys is peculiarly unfavorable for chest-com- 

 plaints. It is to be expected, from its greater elevation, that a still 

 clearer sky and a larger proportion of sunny days would be experienced 

 in the Yellowstone Park, while the wholesomeness of the air would be 

 still more marked, owing to its comparatively greater freedom from 

 zymotic matter. 



The latitude of Davos is 47, and the Yellowstone Park lies almost 

 entirely between the forty-fourth and forty-fifth parallels. The winter 

 temperature at Davos varies from 32 Fahr. down to 22 Fahr., and 

 that of the park would probably observe nearly the same extremes. 

 The selection of suitable sites for hotels and sanitary dwellings is, of 

 course, of the highest importance. The only hotel at present existing 

 the Mammoth Hot Springs Hotel is not favorably situated, but, even 

 in my comparatively limited excursions in the park, I saw numerous 

 most eligible sites for such establishments sites sheltered from north- 

 erly winds, either by abruptly elevated ground or pine-forest, with a 



