THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



3P' MA Y 1823. 



LXVIII. On the Qiiantiti) of Rain collected iii two Rain-gauges 

 placed at different Heights from the Ground, for a Pei'iod of 

 Twelve Months; laith Remarks on the probable Causes of the 

 Increase in the lower Rain-gauge. 



To the Editors (f the Philosophical Magazine and Journal. 



Portsmouth, April 17, 1823. 

 "POURING the last twelve months, from April 1822 to 

 -*-^ March 1823, both inclusive, I have registered the daily 

 quantities of rain from two similarly made lain-gauges ; and 

 the following are the monthly amounts in each gauge : 



In the Rain-gauge three feet above the Grotmd. 



April 2-570 inches; May 1-510; June 0-385; July 4-277; 

 August 1 -815; September 1-685 ; October 6-750 ; November 

 7-500 ; December 2-240 ; January 3-365 ; February 4-585 ; 

 March 2*095. — Total amount 38*777 inches. 



In the Rain-gauge 23 feet above the Ground. 



April 2-270 inches; May 1-365; June 0-325: July 3-850; 

 August 1-705; September 1-620 ; October 6*640; November 

 7-295; December 2-240; January 3-025; February 3-700; 

 March 1-715. — Total amount 35-750 inches. 



Augmented difference in the lower rain-gauge 3*027 inches. 



The greatest monthly increase in the lower gauge occurred 

 in July 1822 and in February 1823, two wet and windy 

 months ; for in July strong gales prevailed eleven days, and 

 in February eight days. The increase in the lower gauge 

 during these two months is almost one-half of the 12 months' 

 difference. I certainly expected to have seen a greater in- 

 crease in the lower gauge than only y'^ more than that in the 

 upper one. It is necessary to observe that the gauge near the 

 ground was about 50 yards distant from the upper gauge, and 

 so placed as only to meet with a partial obstruction on the 

 east side : this, however, is not considered of material conse- 

 quence, as we seldom have rain with an easterly wind; and 

 when it does come from that quarter, it is generally steady for 

 20 or 24 hours. 



\'()1. 61. No. 301. May 1823. S s I would 



