jciV TABLES AND RESULTS OF THE PRECIPITATION 



having a firnilar hole in its centre to reoeive and support the funnel. To prevent 

 the rain-drops which may fall on this board from spattering into the mouth of the 

 funnel, some pieces of old cloth or carpet may be tacked upon it." 



" The object of placing the receiving ring so near the surface of the earth, is to 

 avoid eddies caused by the wind, which miglit disturb the uniformity of the fall of 

 rain." 



" In the morning, (U- after a shower of rain, the bottle is taken up, and its contents 

 measured in the graduated tube, and the quantity in inches and parts recorded in 

 the register. The gauge or tube which was first provided for this purpose will con- 

 tain when fidl only one-tenth of an inch of rain, the divisions indicating hundredths 

 and thousandths of an inch. As this, however, was found to be too small for con- 

 venience, another gauge which contains an inch of rain, and indicating tenths and 

 hundredths, was sent to observers." 



Another and simpler form afterwards adopted by the Institution and Patent 

 Office is one of those which have been experimented on at the Institution. It is a 

 modification of a gauge which was received from Scotland, and which has been 

 recommended by Mr. Robert Russell. It consists (see figure on p. 230 of the 

 Secretary's Annual Report for 1855) of a large brass cylinder two inches in dia- 

 meter, to catch the rain ; a small brass cylinder for receiving the water and reducing 

 the diameter of the column to allow of greater accuracy in measuring the heights ; 

 a whalebone scale divided by experiment, so as to indicate tenths and hundredths of 

 an inch of rain. A wooden cylinder is to be inserted permanently in the ground for 

 the protection and ready adjustment of the instrument. 



To ascertain the amount of water produced from snow, a column of the depth 

 of the fall of snow, of the same diameter as the mouth of the funnel, should be 

 melted and measured as so much rain. The simplest method of obtaining a column 

 of snow for this purpose, is to procure a tin tube about two feet long, having one end 

 closed, and precisely of the diameter of the mouth of the gauge. 



From measurements of this kind, repeated in several places when the depth of 

 the snow is unequal, an average quantity may be obtained. 



To facilitate transportation, the larger cylinder is attached to the smaller by a 

 screw -joint. 



A still simpler gauge has lately been devised by the Secretary of the Institution ; 

 it consists of a cylindrical tube two and a half or three inches in diameter and nine 

 inches in length, closed with a conical bottom or else provided with a small cylinder 

 projecting from a flat bottom, the object of which would be to give precise indications 

 of the smallest quantities, and, with the same instrument, measure the largest amount 

 which falls in any one shower. But, for ordinary observers, it is thought that noth- 

 ing is better than a simple cylinder, three or four inches in diameter, and a wooden 



