350* 



3. On the Results obtained with different forms of Rain- 

 Gauges. By Joseph Atkinson, Esq. Communicated by 

 David Milne, Esq. 



The objects proposed were — 



First, To discover the difference, which the height of Rain- 

 Gauges above the surface makes in the amount of rain received by 

 each gauge. 



Second, To try the effect of an Inclined Funnel, which always 

 presents itself towards the wind. 



Third, To test the action of a Globular Gauge or Sphere. 



Fourth, To investigate whether any and what difference the 

 size of the funnel made in the quantity of raiu received. 



The number of gauges used to accomplish these objects was 

 six; — of which three were horizontal funnels, 12 inches in diame- 

 ter, placed respectively 0, 3, and 6 feet above the surface ; one 

 was a copper sphere, 36 inches in circumference, placed 6 feet 

 above the surface ; one was a funnel, 12 inches in diameter, placed 

 at an angle of about 45 degrees, and 6 feet above the surface — a 

 vane was attached to the rim of this funnel, and this last moved 

 upon a pivot over the receiver ; and the sixth gauge had a funnel 

 of 18 inches diameter, placed horizontally, and six feet above the 

 surface. 



The results obtained from these gauges in twelve months, be- 

 ginning with November 1840, were as follows : — 



First, The excess of the surface gauge over that which was 

 three feet above the ground, was nearly identical with the excess 

 of the latter over that which was six feet above ; the excess in 

 the first mentioned case being 1.816 inches — in the latter, 1.865 

 inches. 



Second, The inclined and moveable funnel always took more 

 rain than the horizontal funnel on the same level during strong 

 winds, and less during calm winds. The difference between these 

 two gauges was, in twelve months, only 1.887 inches. In thatt 

 period, the horizontal funnel on the surface had taken 1.804 inches 

 more rain than the inclined funnel, the latter being placed 6 feet 

 above the surface. 



TJiird, The globular gauge, instead of receiving more rain than 

 the common horizontal funnel at the same level, as might have 

 been expected, received 0.560 inches less in the twelve months. 

 In the first six months, it received more rain than the horizontal 

 funnel, but during the warm months it received considerably less. 

 During the cool months it represented very fairly the mean of the 



