Quantities Given in Dr. Marloth's Paper, 415 



measuring off on a diagonal scale, will give a rough approximation 

 to the true area : — 



Upper ring, inside surface = 15'371 sq. in. 



Upper ring, outer surface = 18'394 ,, 



Wire netting (51-84 in. x 0*05 in.) = 8-143 



Four wire rods (each 9-2 in. x 0-16 in.) = 18-498 



Eighteen reeds (each 10*5 in. x 0*09 in.) = 53-438 ,, 



Rain-gauge (decreased in diameter to 4-82 in.)= 18-247 ,, 



Approximate catchment area =132-091 ,, 



This result is well under the actual area, as certain surfaces, such 

 ■as the bent-over ends of the reeds, part of the lower wire netting 

 which has been so pulled up as to project above the gauge and thus 

 act as an addition to the receiving surface, as well as other small 

 items, have been omitted. 



In fact this superstructure practically acts as a sponge or filter, 

 having an area approximately equal to 114 square inches, which 

 with the receiving surface of the gauge itself brings it up to about 

 132 square inches. 



Now as the water (79-84 inches) collected by this gauge repre- 

 sents the depth as measured off by means of a measure graduated 

 to show inches of rainfall collected by a rain-gauge 5 inches in 

 diameter {i.e., having an area of 19*635 square inches), it follows 

 that— 



79-84 in. x 19-635 sq. in. = 1567*6584 cubic in. = 



the total amount collected. 



Therefore this quantity divided by the approximate area found as 

 above would give a result closely approaching the true depth of 

 rainfall — ^ 



.-. 1567-6584 cubic in. -^ 132-091 sq. in. = 11-87 in. 



If we assume that the 4-97 inches collected by the plain rain- 

 gauge was equal to the rainfall collected by this second gauge, sub- 

 tracting we get 



11-87 in. -4-97 in. = 6-90 in. 



as the amount deposited from the " South-East Cloud." This 

 amount divided by 57, the number of days during which the experi- 

 ments were carried on (December 21, 1902 to February 15, 1903), 

 gives an average deposit of 0*12 inch locr diem, on the assumption 



