JAN. — MAR. 1857.] Memo, on Rain Ganges y ^c. 203 
V. Memo, on the subject of Rain Gauges for the Provinces 
of Madras. By W. EC. 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 
of an inch of rain fallen, and a cylinder /m//, or a *' measure" 
denotes y ^ 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 y'^, or -0625 of an inch of rain and iV of an inch deep in 
the cylinder denotes y^^ 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 y^-^ of an inch fall 
of rain, whereas y"^^ of an inch is the utmost we can want from 
such country Registers as these. In the next place, if there is at 
