650 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the places of summer resort, water cures, etc. The most un- 

 favorable condition of the atmosphere for the earth is a long 

 period of prevailing calm, or very slight breezes. In many- 

 climatic sicknesses, as malaria, yellow fever, etc., it ap- 

 pears that when they become epidemic, there has preceded 

 that time, a long period of calm Aveather, in which the lowest 

 stratum of air rested quietly upon the earth. Hence arises 

 the Spanish motto : " In Madrid the air kills men, but never 

 blows out the light." The salubrity of the air over any re- 

 gion, therefore, depends upon its renewal by the winds, quite 

 as much as the salubrity of the air in a room depends 

 upon proper ventilation. It follows that, in considering the 

 influence of climate on health, we must observe both the 

 strength and the direction of the wind, and especially the 

 calms. For this purpose Prestel has constructed a peculiar 

 instrument, which he calls the pendulum anemometer, which 

 records automatically both the direction and the pressure of 

 the wind. Die Wmde^ Frestel, 1872. 



THE INFLUENCE OF CLIMATE ON MORTALITY. 



The report of the Board of Health for the City of Phil- 

 adelphia, for the year 1872, contains some graphic illustra- 

 tions of the intimate connection between the vicissitudes of 

 climate and the mortality from various classes of disease ; 

 and if the facts therein discussed are not entirely new, it is 

 at least important that they should be demonstrated so clear- 

 ly as is done in this work. The curves indicating the course 

 of the mortality from pneumonia and bronchitis rise rapid- 

 ly in cold weather, and rapidly decline as the temperature 

 of the year rises ; while consumption pursues a more equit- 

 able course, being only slightly modified by the variations 

 in temperature. The heaviest mortality from small -pox 

 usually occurs in March; but in 1872 the greater number 

 of deaths took place in January, and the smallest in De- 

 cember, a departure from the general rule. A very re- 

 markable connection is apparent between the extreme hot 

 weather of the first week in July, with its enervating moist 

 atmosphere, and the mortality from cholera infantum and 

 the zymotic diseases, both which classes of disease swept 

 away during that week one third of those who died from all 

 causes whatever ; and in general the total mortality from all 



