64 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 4 
By, and commonly before, the time this stationary cloud has formed 
over the valley, the air has become so thoroughly mixed that most of 
the wind phenomena described above are fully developed. In par- 
ticular the descending currents reach the earth along the tempest 
belt and there rebound, giving the mysterious leeward calm beyond. 
Complete clouding.—Commonly the crest cloud along the mountain 
grows heavier, the scud thicker and more enduring, and the bank of 
stationary cloud over the leeward valley broader and deeper until 
all merge together and the whole sky is blotted out by a continuous 
cloud canopy; a sequence of phenomena owing entirely to the increas- 
ing humidity of the air, and the consequent lowering of the dewpoint, 
as the wind continues to blow from warmer and more humid regions. 
Rain or snow.—Shortly after the clouds have merged into a con- 
tinuous sheet, precipitation usually begins, and commonly lasts 
anywhere from several hours to an entire day, or even two days. It 
is the final result, in part, of the increased humidity of the winds, and 
also in part of the convection and consequent cooling of the air incident 
to the cyclonic storm then prevailing. 
After the rain, or snow, there follows, of course, the process of 
clearing up, but this process has no distinct mountain peculiarities 
and hence need not be discussed here. 
There are of course still other phenomena that might be considered 
in this connection, but the above are, perhaps, the more interesting 
and the more important of the many generally associated with the 
roaring of the mountain, and enough to assure us that among forested 
mountains, especially 
“In winter, when the dismal rain 
Comes down tn slanting lines, 
And Wind, that grand old harper, smites 
His thunder-harp of pines,”’— 
—Alexander Smith. 
when the muffling leaves are gone and the twigs are free to mingle 
their myriad aeolian tones, the coming storm is heralded by the 
murmuring of the forest and the roaring of the mountain. In proverb 
form: 
When the forest murmurs and the mountain roars, 
Then close your windows and shut your doors. 
