676 



THE POPULAR SCIENCE MONTHLY. 



p. M. 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 disa- 

 greeable to be out of doors. We speak of the dust, for it must be re- 

 membered 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. 



Sunshine. — 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 a. m. or at 1 r, m. or at 5 p. m., 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 win- 

 ter of 1884-'85 when the sun did not shine upon Denver between the 

 hours of 9 A. M. and 5 p. m., 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. 



* The figures in this table should read so many miles per diem. In the former tables 

 the velocities are given in miles per horam. 



While in New York recently, we tried to obtain data of observations at 9 a. m., 1 and 

 6 p. M., local time, as a means of comparison, but they were not to be had at the Signal- 

 station. 



