336 ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 



A temperature between 30° and 42° seems to be very favorable 

 to chills, etc., possibly owing to the humidity and conductivity of the 

 air being- greater than at lower temperatures, to the absence of the 

 sharp, bracing action of frost, and to the greater number and vitality 

 of microbes in the air than at lower temperatures. Dry, cold winds 

 may have a chilling effect equal to a calm, damp air of the same tem- 

 perature. 



With regard to all these matters of air and health, or season and 

 health, a great deal might be done for the prevention of disease by the 

 public issue of forecasts, or monitions, at appropriate times, showing 

 the character of the maladies connnon at the season, or to be expected, 

 and giving some plain directions. If this were done weekly, it is prob- 

 able that the number of lives saved would be larger than those saved 

 by the weather forecasts for coast purposes. 



EXPLORATION OP THE ATMOSPHERE IN CONNECTION WITH WEATHER 

 FORECASTS AND A MORE EXACT KNOWLEDGE OF ATMOSPHERIC 

 CONDITIONS. 



Captive balloons regularly used, weather permitting, at a number of 

 well-distributed stations, would give valuable information in addition 

 to the ordinary items furnished for the purposes of governmental fore- 

 casting. Mountain observatories have already been long enough 

 established to give results which show a different distribution of tem- 

 perature and pressure before different types of weather. But balloons 

 might be fitted with instruments which would show the pressure and 

 temperature at several heights in succession during ascent and descent, 

 and this information would very probably be important in forecasts, if 

 the height attained were sufficient. Balloon ascents have shown the 

 atmosphere to be frequently arranged in blocks or masses of air of 

 very different temperatures within a short distance of each other, and 

 occasionally in an inverse order to that which might be expected from 

 the law of diminution with height. Thus, on July 17, 1862, the ther- 

 mometer on the earth was 59 ; at 10,000 feet, 26 ; at 15,000 feet, 31 ; at 

 19,500 feet, 42; but on descent a little below this height, the tempera- 

 ture fell with extraordinary rapidity to 16. Strata much below the 

 freezing point may have a few hundred or thousand feet above them, 

 currents of air at 40 or 42. The variations are often very large and 

 rapid. The greater the height, within the limits of the cirrus cloud 

 at least, the greater apparently are the differences between adjacent 

 strata or masses of air. Irregularity of temperature and humidity dis- 

 tribution must have a considerable influence on the consequent weather, 

 and a series of balloon observations for a term of years at a good num- 

 ber of stations would probably be of very considerable service both 

 for theoretical and practical purposes. 



Free balloons for exploration, such as have given good results in 

 France, might be contrived to ascend to some desired height, and then 



