42 



PROCEEDINGS OF THE AMERICAN ACADEMY 



TABLE II. 

 Relation of Wind and Rain : Storm of July 9, 1885. 



The most obvious relation of wind and rain is, that a brief heavy 

 squall shortly precedes a heavy rain-fall ; and this is so commonly 

 stated to be the case that one is tempted to regard the first as the 

 effect of the second. But the relation has two exceptions : first, as in 

 the above table, where heavy winds occur with light rain, although in 

 those cases heavy rain may have occurred near by ; second, in other 

 storms there is often heavy rain and no severe wind. More data are 

 needed before attempting further generalization. 



It has been stated that a ragged fringe of cloud always advances in 

 the front of a storm that is accomj^anied by a squall.* The observa- 

 tions made at a number of stations seem to confirm this opinion. The 

 following may be quoted : Northfield, Mass. : A bank of inky clouds 

 rose from the N. W. bordered by a line of fog ; a violent gale sprang 

 up suddenly ; soon after this, the line of fog passed the zenith, and the 

 air was suddenly darkened. Amherst, Mass. : A scud of low black 

 clouds was blown rapidly from N.W. at about the time of high N.TV. 

 wind ; heavy rain soon after. AUenstown, N. H. : An arch of boiling 

 scud before the heavy storm-clouds, followed shortly by violent W. wind, 

 with rain whirling in sheets. Tyngsborough, Mass. : Air calm ; high 

 cumuli, "preceded by a ragged and turbulent gray squall-cloud"; seven 

 minutes later, a heavy squall, air filled with dust, and " white caps " 



- * Hann, Beitrag zur Morphologie der Gewitterwolken. Zeitschrift fiir Me- 

 teorologie, 1880, xv. 434. 



