186 Mr Marshall's Meteorological Observations, #c. 



collected that but 4.012 inches have fallen in twenty -one days, or 190 inch 

 each day on an average for that time, the greatest quantity on any one day 

 was 472 inch, except on the 28th, when 1.032 inch was taken. The winds 

 from the N. E. have prevailed since about the middle of the month, with 

 some variations. The most prevalent through the month has been west. 

 The barometer has attained but a low elevation, and though the average 

 temperature is considerable, the air has at times been cold, as is always 

 the case when the wind is in the E. and N. E. There was a little snow 

 on the 6th, which disappeared in the course of the day ; and a hail show- 

 er on the evening of the 24th. The swallow was seen this season for the 

 first time by the writer on the 13th. 



May. 



Barometer. Inches. 



Maximum on the 1st, . - - 30.17 



Minimum on the 25th, .... 29.29 



Mean height, - - - - 29.69 



Thermometer. 

 Maximum on the 28th, - - 68° 



Minimum on the 1st, - - - 35° 



Mean height, - - - - r 53.12° 



Quantity of rain, 1.961 inch. 

 Number of rainy days, 1 0. 

 Prevalent wind, west. 



Though the prevalent wind is stated as west, it must be understood with 

 this limitation, as applying to the day-time. From the beginning to the 

 latter part of the month, in whatever direction the wind blew during the 

 day, in the evenings and mornings it was almost uniformly N. E. and E. 

 and it is probable that this was the prevailing wind through the nights. 

 The dryness of these winds is proverbial, and their effects on delicate con- 

 stitutions well-known. On the evening of the 27th we had an appalling 

 thunder storm. This did not cool the air, which had previously been sul- 

 try, so much as might have been expected, nor was the barometer affected 

 during its continuance. Indications of a change in the weather on the 

 23d and 24th. Among these were whirls of dust, and a remarkable one 

 occurred on the evening of the 23d by the side of the river Kent, and in 

 the town. The dust of the road was raised in a dense column, which 

 was estimated by different observers to be from 50 to 100 yards in height, 

 and at least 5 yards in diameter. The top of the column being the 

 broadest part, it appeared like an inverted cone. It was raised by a gyra- 

 tory motion in the air, whilst round the column no agitation was percep- 

 tible, though several persons who were passing at the time stood within a 

 few feet distance. After continuing about two minutes, it crossed the river, 

 and then proceeded about 200 yards in an easterly direction, raising and 

 dispersing the dust which it met with on the ground. In a few minutes 

 after the same appearance was repeated, though not in so distinct a column, 

 and originating within a few yards of the former. The latter whirlwind 

 passing over a coal wharf, raised the coal dust in a dense black column to 

 the height of about 40 feet. 



