456 WRITINGS OF JOSEPH HENRY. [1865 



The peculiar diseases of a region are principally dependent 

 on its climate; an extreme variation of temperature in a 

 large city is invariably attended with an increase of the 

 number of deaths. The degree and variation of the mois- 

 ture at different times and in different places have also a 

 great influence on diseases, and the more the means of study- 

 ing the connection of these elements and the corresponding 

 condition of the human body are multiplied the more will 

 the art and the science of medicine be improved. I may 

 mention that scarcely a week passes at the Institution in 

 which application is not made for meteorological informa- 

 tion relative to different parts of this country, with the hope 

 to improve the condition, if not restore the health, of some 

 patient. The knowledge which at present exists however 

 as to the connection of climate and disease, particularly in 

 our own country, is — in comparison to what might be ob- 

 tained — of little significance. 



No other part of the world can at all compare with this 

 country in the conditions most favorable to the advancement 

 of meteorology, by means of a well-organized and properly 

 sustained system of combined observations. Such a system 

 extending from east to west more than two thousand miles 

 would embrace in its investigation all the phenomena of the 

 great upper current of the return trade wind, which con- 

 tinually flowing over us at a high elevation carries most of 

 the disturbances of the atmosphere eastward. It would also 

 include the effects produced by the polar and equatorial 

 currents as they contend for the mastery along the broad 

 valley which stretches without interruption from the arctic 

 circle to the Gulf of Mexico, and would settle with precision 

 the influence of the great fresh-water lakes in ameliorating 

 the climate of the adjacent regions. But above all, in a 

 popular view, it would furnish the means more effectually • 

 than any other system — of predicting the approach of storms 

 and of giving the ships of our Atlantic coast due warning 

 of the probability of danger. 



