Page:Popular Science Monthly Volume 28.djvu/694

 it is either from the north or west. They do not, however, show the well-recognized daily change from the south at night to the north during the day. Furthermore, the observations have reference only to Denver, and can not be taken as a guide for other places, where the peculiar topography must exert a controlling influence.

Moreover, the tables teach most conclusively that the mean hourly motion, at any one of the three observations, is mild, and probably rather less than would prevail in New York city at the same hour of the day. Certain it is that in 1880 the corresponding mean velocities for the twenty-four hours were as follows, viz.:

While our tables show that the average hourly movement of the wind is moderate, it is true, as some object, that we do have occasional squalls, when the dust is picked up by the wind and when it is disagreeable to be out of doors. We speak of the dust, for it must be remembered that snow does not lie on our ground, even in midwinter. But such squalls are no more frequent than one will meet with in the autumn months in Boston. In violence they bear no comparison, as we can testify from personal experience, to many a tornado that has occurred of late years in the valley of the Connecticut River, and should by no means be confounded with the blizzards of the North-west nor the cyclones of Kansas.

—We next learn, from a consideration of the tables, that while there occurred days in the winter under observation when the sun was not shining at 9 or at 1, or at 5 , as the case might be, there were only eleven days in the whole eight months when the heavens were completely and wholly obscured at all three observations. In other words, there were only eleven days in the winter of 1884-'85 when the sun did not shine upon Denver between the hours of 9 and 5, and they occurred as follows, viz.:

We may fairly conclude from these figures that there were only eleven days, out of the two hundred and forty-two, when the invalid was detained in doors all day long for want of sunshine,