jan. — -mar. 1857.] Memo, on Rain Gauges, fyc. 203 



V. Memo, on the subject of Bain Gauges for the Provinces 



of Madras. By W. H. Bayley, Madras Civil Service. 



The Rain Gauge now in use is a Funnel of Copper, 12 inches 

 in diameter, and is inserted in a chatty or any kind of vessel. 

 "When rain has fallen the water is emptied out into a copper 

 cylinder, 8 inches deep, and 3 inches diameter. 



As the diameter of the Funnel is 4 times that of the cylinder, the 

 area of the former is 16 times that of the cylinder, so that when 

 the rain water is poured into the cylinder, every inch deep shows 

 T \ of an inch of rain fallen, and a cylinder full, or a " measure" 

 denotes T ~ or J an inch of rain. 



A dipping stick divided to inches and tenths is used to measure 

 portions of the cylinder. One inch in the cylinder as before stated 

 denotes T \, or '0625 of an inch of rain and fa of an inch deep in 

 the cylinder denotes T ^ or -00625 of an inch. 



The Talook Officers are directed to enter in their Books, Mea- 

 sures, Inches and Tenths. And these are to be reduced in the Board's 

 Office to inches and decimals of rain, by using the following 

 Multipliers. 



Suppose the Return is. 



Measures. Inches. Tenths. 



13 7 8 



13 X '5 — 6'5 .Inches of rain. 



7 X -0625 = 0-4375 do. 



8 X -00625 = 0'0520 do. 



6-9875 Inches of rain fallen. 

 The objections to this plan are two ; 



First, the apparatus is made much larger than is required, 

 one-tenth of an inch in the cylinder denotes T £- 0 of an inch fall 

 of rain, whereas of an inch is the utmost we can want from 

 such country Registers as these. In, the next place, if there is at 



