134 DOMESTIC WATER SUPPLIES FOR THE FARM 



in the afternoon, while a considerable number flow only during 

 storms. Others, though flowing constantly, have their yield 

 greatly augmented at such times, the effect being especially 

 marked in wells of large diameter whose head is ordinarily barely 

 sufficient to overflow the pipe. In such wells the discharge may 

 be increased fifty or one hundred per cent or even more during 

 the passage of marked weather disturbances. The increase of 

 flow under such conditions is probably a universal phenomenon, 

 though in copiously flowing wells of high head it is often inap- 

 preciable. 



Roiliness of Well Waters. Most wells normally yield clear 

 water. In isolated cases, however, the water, which is ordinarily 

 clear, becomes cloudy or milky on the approach of storms, and 

 more rarely turns to a yellowish or reddish color under the same 

 conditions. Examination shows the milkiness to be due to the 

 presence of a slight amount of suspended silt or clay, and the yel- 

 low and red colors to fine particles of iron oxide held in suspension, 



Blowing Wells. Wells that emit currents of air from their 

 mouths are called blowing wells. Blowing is not confined to 

 drilled wells, but is noted in many dug wells, the air escaping 

 through cracks or other openings in the covers. It was reported 

 to the writer that the current passing out through the knot hole 

 in the cover of one well was strong enough to lift a hat several feet 

 into the air. At some times the whistling of the escaping air 

 through the planks or pipes can be heard for several 'rods; at 

 other times the current is strong enough to operate small whistles 

 whose sound is loud enough to be heard for a mile or more in 

 still weather. In some wells a dull roaring sound is heard as the 

 air rushes through the casing; in other wells the air can be heard 

 bubbling through the water. 



Breathing Wells. In most blowing wells the blowing is not 

 continuous but alternates with sucking; such wells are more 

 properly known as breathing wells. Probably most of the 

 "barometer" or "weather" wells are of this class, although the 

 indraft is usually less rapid and less conspicuous than the outdraft, 



