58 ELECTRICITY AND GALVANISM. 



England there is a degree of regularity, for the easterly 

 wind usually prevails from about the Vernal Equinox to 

 somewhat beyond the Summer Solstice, and then the 

 westerly wind prevails for the remainder of the year. 

 This is of course subject to exceptions. Within the 

 tropics a very great regularity in the wind prevails ; it 

 blows at various places, for six months in one direction, 

 and six months in the opposite direction, throughout the 

 year. The velocity of the wind varies from one mile in 

 an hour to 100 miles ; from a scarcely perceptible breath 

 to a terrific hurricane. 



A most exceedingly rapid and impetuous wind moving 

 in a spiral manner, called a Whirlwind, sometimes takes 

 place. This usually occurs after very hot weather, and 

 in the warmer climates, and has by some been attributed 

 to a stream of elastic matter rushing violently out of the 

 earth. Whirlwinds and Water-spouts most probably 

 arise from the like cause, which is intimately connected 

 with Electricity. 



The following are the principal instruments \ised in 

 Meteorology. The Anemometer, which measures the force 

 of the wind ; the Atmometer, the quantity of water 

 evaporated in a given time 5 the Barometer, the weight, 

 or pressure of the air; the Cyanometer, the intensity 

 of the blue colour in the atmosphere j the Drosometer, 

 the quantity of dew that falls ; the Eudiometer, the 

 pureness of the air ; the Hygrometer, the humidity of 

 the air ; the Ombrometer, the quantity of rain that falls ; 

 and the Thermometer, the temperature of the air. 



ELECTRICITY AND GALVANISM. 



Origin of Electricity Electrics Conductors or Non-electrics Mode of exciting 

 Electricity Electric Machine and Apparatus described Electric Battery 

 Electrophorus Electrometer Electricity identified with Lightning Para- 

 tonneres or Conductors Electric Fish Galvanism or Voltaic Electricity 

 Voltaic Pile described Galvanic Excitement of the Body, &c. &c. 



THE origin of the science of Electricity may be traced 

 to Thales the Milesian, who flourished about COO years 

 before the Christian era, and was particularly celebrated 

 for his improvements in the different sciences. He first 



