+-------------------------------------------------------------------+ | MONTHS. |INCHES.|DAYS.|HOURS.|| MONTHS. |INCHES.|DAYS.|HOURS.| |-----------+-------+-----+------++------------+-------+-----+------| |January. | 1.86 | 19 | 88 ||July. | 2.27 | 17 | 68 | |February. | 0.37 | 9 | 25 ||August. | 2.45 | 12 | 72 | |March. | 3.40 | 22 | 130 ||September. | 1.70 | 12 | 55 | |April. | 2.34 | 14 | 80 ||October. | 3.23 | 21 | 94 | |May. | 3.04 | 16 | 90 ||November. | 1.12 | 10 | 53 | |June. | 2.45 | 20 | 83 ||December. | 1.44 | 17 | 66 | +-------------------------------------------------------------------+ "During the year 1862, the rainfall amounted to 25.67 inches. Rain fell on 179 days, that is, on nearly every other day. The hours of rain were estimated at 904; therefore, if the rain had fallen continuously, it would have lasted nearly 38 days and nights."[10] The value of similar estimates of the rainfall by numerous observers would be very great to meteorology. =116. The principle of measurement= in all these gauges is the relation existing between the areas of the collecting and receiving surfaces; that is, between the area of the funnel into which the rain falls, and the area of the cylinder which receives it. In Howard's and Glaisher's gauges, this cylinder is virtually the measuring glass itself; in the others, above described, the measuring scales show the same depth of water as in the cylinder of the gauge. The cylinder being of less diameter than the funnel, and receiving all the rain collected by the funnel, it follows that its contents will have an increased depth. Now equal cylindrical volumes, having different diameters, are to each other in length inversely as the squares of the diameters. Hence, if the funnel be 9 inches and the cylinder 3 inches in diameter, a fall of 1 inch of rain will be represented in the gauge by 9 inches; for 3 squared : 9 squared :: 1 : _x_ = 9. In this case, therefore, a length of nine inches of the measuring glass, tube, or scale, would represent an inch of rainfall, and be divided into tenths and hundredths of the artificial inch. =117. Position for Rain-Gauge, &c.=--Rain gauges should be placed on the ground, in any position exposed to a free fall of rain, snow, or hail, where neither walls, buildings, nor trees shelter or cause eddies of wind. They should be supported by a frame, or other means, to prevent them being blown down by the wind, but so that they can be readily emptied. During snow or frost, the gauge must be watched, and its contents melted by placing it in a warm room, either when the amount is to be measured, or the funnel is filled up with snow. A tin vessel of equal area to the funnel may at such times be useful as a substitute.