OF ARTS AND SCIENCES. 29 



July 22, 23, 24. These days were occujiied with the passage of 

 an area of high pressure, with fair, warm weather, and had only three, 

 three, and seven reports respectively : the most severe of the last day 

 was in central New Hampshire, where our lack of observers prevented 

 its receiving more notice. 



July 25. An area of low pressure moved from Lake Michigan 

 on the 24th north of the St. Lawrence, and was north of the Gulf on 

 the afternoon of the 25th, when several storms occurred in southern 

 New England, after an oppressively hot day. The complication of 

 successive storms at a number of stations makes it difficult to deter- 

 mine their advance. The most distinct one moved from the Connecti- 

 cut valley, at 1A\ east-northeast across Massachusetts, reaching the 

 sea about 16^', and having a velocity of about 35 miles an hour: its 

 rain-front stood northwest and southeast, a somewhat unusual atti- 

 tude. Heavy storm-clouds were developed over southern central 

 Connecticut about 15^^ to IG"*, but they gave only moderate rain. 

 Few reports make mention of violent winds, although the rain-fall was 

 not infrequently heavy. These storms did not mark any distinct 

 change of weather, as the mean maximum temperatures for the 25th 

 and 26th were 88° and 87°. 



July 26. On this date there was still low pressure over the Gulf 

 of St. Lawrence, and high pressure north of the Lakes. The day 

 became oppressively hot, but only two thunder-storms of any defined 

 form can be recognized. One crossed the Connecticut valley near 

 Amherst, Mass., about noon, moving from northwest to southeast, 

 with heavy rain preceded by high northwest wind, and cooling the 

 air from 90° down to 80° ; it seems to have been short-lived, as 

 stations farther east did not report it. The other and larger one 

 bejran south of Framingham and Natick and north of Medfield and 

 Norwood, about r2'\45, and moved southeast, crossing Martha's Vine- 

 yard at 15'M0 to 15\40; its velocity therefore averaged about 23 

 miles an hour, but the time of the storm's arrival at intermediate 

 stations implies a gain in velocity in the latter part of its course. 

 The wind of the day was generally northwest ; it was not seriously 

 affected by this storm till the cloud had passed Taunton (13'\50) and 

 reached East Freetown (14''.14) ; here and beyond, the wind before 

 the storm was light southerly, with temperature 92° inland, and 85° to 

 80° on the coast; then, with the beginning of the rain, the wind-squall 

 came high from the northwest, and the temperature fell ten or fifteen 

 degrees in half an hour or less. The rain became very heavy, and 

 numerous lightning strokes are reported near New Bedford and on 



