IN RAIN AND SNOW IN THE UNITED STATES. Xlll 



represents a hundredth of an inch of rain fallen into the ombrometer. These degrees 

 are large enough to permit us to estimate the thousandths of an inch, etc., etc. 



" The snow-gauge should be supported vertically, in an open place, between 

 three short wooden posts, its opening being about two feet from the ground. It 

 should be employed in the following manner : When only a small quantity of snow 

 falls, or of snow alternating with rain, or of dry and line snow, driven by the wind, 

 it should be collected in the snow-gauge, as would be done in the obrometer. But 

 when the snow falls in a sufficient quantity to cover the ground more than an inch deep, 

 the vessel must be emptied, and plunged, mouth downward, into the snow, until the 

 rim reaches the bottom. A plate of tinned iron or a small board may then be passed 

 between the ground and the mouth of the gauge, and the whole reversed. In this 

 way a cylinder of snow, of which the base is superficially one hundred inches, will 

 be cut out and received into the vessel. The operation may be facilitated by placing 

 on the ground a platform of strong board or plank, two or three feet square, on which 

 the snow is received. The place selected for this purpose must be where the snow 

 has not been heaped up or swept away by the wind, and where it presents, as nearly as 

 possible, the mean depth of the layer that has fallen. In order to take only the snow 

 which may fall in the interval between two observations, the board should be 

 swept after each measurement, and the place designated by stakes. The collected 

 snow must be melted by placing the gauge, covered with a board to prevent evaj)ora- 

 tion, in a warm room, and the quantity of water produced measured by pouring it into 

 the glass cylinder. The rain water and melted snow water must be separately 

 entered in the journal. During abundant rain-falls it is well to measure the water 

 more than once a day, or at least immediately after the rain, and the quantity of rain 

 fallen, together with the time it has lasted, is to be noted. When it freezes, it will 

 be necessary to protect the receiver by filling in the interior of the barrel with 

 straw." 



" A series of observations has been made at the Smithsonian Institution with 

 rain-gauges of different sizes and different forms, the result of which, as far as the 

 observations have been carried, is to induce a preference for the smallest gauges. 

 The one which was first distributed by the Institution and the Patent Office to the 

 observers (represented on p. 229 of the Secretary's Report for 1855), consists of a 

 funnel terminated above by a cylindrical brass ring, bevelled into a sharp edge at 

 the top, turned perfectly round in a lathe, and of precisely five inches diameter. 

 The rain which falls within this ring is conducted into a two-quart bottle placed 

 below to receive it. To prevent any water which may run down on the outside of 

 the funnel from entering the bottle, a short tube is soldered on the lower part of the 

 former and incloses the neck of the latter. The funnel and bottle are placed in a 

 box or small cask, sunk to the- level of the ground, which is covered with a board 



