190 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



and Comfort, in which he maintains that the delightful sum- 

 mer condition of temperature, 62 to GS, and relative humid- 

 ity, 80 to 85 per cent., is not desirable, or even attainable, at 

 oilier seasons in the heating of dwellings, etc. The dry air 

 of America possesses both curative and preventive qualities 

 of great value; moist air that promotes vegetable growth is, 

 on sanitary grounds, not desirable for breathing. The au- 

 thor has found the dew-point far below the freezing-point of 

 Mater in well-warmed and ventilated rooms where there was 

 nothing of that sensation of dryness that is usually held to 

 accompany the heat of a furnace when not supplied with wa- 

 ter for evaporation. New houses, that are accounted un- 

 healthy in Europe, are not so in America. Gas burned in 

 rooms produces much less unpleasant effects in America than 

 in England. What is needed is an equality in relative hu- 

 midity between the interior and exterior air. Thus, if the 

 outer temperature be and relative humidity 40 per cent., 

 and the interior temperature be 70, Ave ought to raise the 

 interior humidity to 40 per cent, by adding a little water, and 

 not to 80 or 90 per cent, by adding too much. 



The effect of diminished atmospheric pressure upon the hu- 

 man body was discussed by Mermod in the Bulletin of the 

 Switzerland Society of Natural Sciences. His observations 

 extend through three years, and relate mostly to himself: 

 first, he finds that the systematic residence in higher regions 

 is attended by an increase in the pulse, but not in the fre- 

 quency of breathing; second, therefore the ratio between the 

 frequency of respiration and heart-beats grows smaller as 

 we ascend to higher stations; the temperature of the body, 

 however, was unchanged; third, the absolute and relative 

 amounts of carbonic-acid gas can be regulated by moving 

 the patient to a higher or lower level. 



From an inaugural dissertation, by M. Schyrmunski, of Wil- 

 na, on the Iniluence of Rarefied Air on the Human Body, we 

 extract the following notes as interesting to the invalids who 

 resort to Colorado and other high regions: The first accurate 

 observations on the subject were made by Saussure on the 

 occasion of his ascent of, Mont Blanc in 1787. The princi- 

 pal subsequent observations and publications on this subject 

 have been A. von Humboldt's ascent of Chimborazo; Boussin- 

 gault's ascent of Chimborazo in 1831 ; R. von Schlaginweit's 



