87 



A few years since, the grove was felled, and the ground turned again to a pasture. 

 The spring disappeared with the wood, and is now as dry as it was ninety vears. 



ago." 



IMPORTANCE OF SNOW. 



The quantity of snow that falls in extensive forests far from the open 

 country, has seldom been ascertained by direct observation, because there are 

 few meteorological stations in or near the forest. According to Thompson, the 

 proportion of water which falls in snow in the northern States does not exceed one- 

 fifth of the total precipitation, but the moisture derived from it is doubtless con- 

 siderably increased by the atmospheric vapour absorbed by it, or condensed and 

 frozen on its surface. Though much snow is intercepted by the trees, and the quan- 

 tity on the ground in the woods is consequently less than in open land in the first 

 part of the winter, yet most of what reaches the ground at that season remains under 

 the protection of the wood until melted, and as it occasionally receives new 

 supplies, the depth of snow in the forest in the latter half of winter is considerably 

 greater than in the cleared fields. Measurements in a snowy region in New Eng- 

 land in the month of February, gave a mean of thirty-eight inches in the open, 

 ground and forty-four inches in the woods, but the actual difference between the 

 quantity of snow in the woods and that in the open ground in the latter part of 

 winter, is greater than the measurements would seem to indicate. In the woods 

 the snow, which remains constant, is consolidated by a pressure, while in the 

 open ground, being blown off, or thawed several times in the course of the winter, 

 it seldom becomes as densely packed as in the woods, except in the bottom of 

 valleys or other positions where it is sheltered both from wind and sun. 



The water imbibed by the soil in winter sinks until it meets a more or less 

 impermeable or a saturated stratum, and then, by unseen conduits, slowly finds 

 its way to the channels of springs, or oozes out of the ground in drops, which 

 unite in rills, and so all is conveyed to the larger streams, and by them finally to 

 the sea. 



IMPORTANCE OF SUMMER RAINS. 



In countries like the United States (and Canada) where rain is comparatively 

 rare during the winter and abundant during the summer half of the year, common 

 observation shows that the quantity of water furnished by deep wells and by 

 natural springs depends almost as much upon the rains of summer as upon those 

 of the rest of the year, and, consequently, that a large portion of the rain of that 

 season must find its way into strata too deep for the water to be wasted by evapo- 

 ration. 



According to observation at one hundred military stations in the United 

 States, the precipitation ranges from three and one-quarter inches at Fort Yuma 

 in California, to about seventy-two inches, at Fort Pike, Louisiana, the mean for 

 the entire territory, not including Alaska, being thirty-six inches. In the different 

 sections of the Union it is as follows : 



IS! ortheastern States 41 inches. 



New York 36 



Middle States 4(M " 



Ohio , ...40 



Southern States 51 



S. VV. States and Indian Territories 39J " 



Western States and Indian Territories 30 



Texas and New Mexico 24i " 



California 1 8| " 



Oregon and Washington Territory 50 



