I90I.] 



FAIRCHILD — CYCLONIC STORMS. 



301 



The President gave an illustrated lecture entitled 



CYCLONIC STORMS AND ROCHESTER WEATHER. 

 By Herman L. Fairchild. 



CLIMATE AND WEATHER. 



The atmospheric conditions of any place or region when averaged 

 through a long period of time are called the "climate." In other 

 words climate is the average value of the meteorological elements of 

 the place. Thus we say that a certain locality has a hot or a cold 

 climate, or wet or dry, according as the average conditions of the 

 locality vary from the normal for that latitude, or for the continent. 



"Weather" is the term applied to the changing or fluctuating 

 conditions of the atmosphere, the succession of phenomena, during 

 short periods of time. Localities may have "climate" and not have 

 "weather." Rochester has both. Places which have only two sea- 

 sons during the year, perhaps a wet season and a dry season, with the 

 atmospheric conditions repeated day after day during each season, 

 have, speaking correctly, only climate. The people of such regions 

 do not have one prolific topic of small talk which helps to make life 

 worth living. Rochester has an abundance of " weather," or frequent 

 changes in the conditions of the atmosphere, and yet has at the same 

 time one of the most equable and finest continental climates in the 

 world. The daily changes here are not great for a continental climate, 

 and the seasonal averages are near the normal. W^e will make some 

 comparisons below. 



METEOROLOGICAL ELEMENTS. 



The elements of meteorology which make climate are: (i) Tem- 

 perature ; (2) moisture, in varied forms as invisible vapor, dew, fog. 



