796 THE POPULAR SCIENCE MONTHLY. 



winter. Occasionally storms depart very much from the aver- 

 age track, their course being sometimes directed toward the 

 southeast and sometimes toward the northeast, and occasion- 

 ally their course for a day or so has been almost exactly north. 

 Their average velocity of progress is twenty-six miles per hour, 

 being twenty-one miles in summer and thirty miles in win- 

 ter ; but sometimes they attain a velocity of fifty miles in an 

 hour, and sometimes they remain for a day or two sensibly sta- 

 tionary." 



Blodgett, Mitchell, Coffin. Several other names deserve 

 mention, as belonging to earnest investigators and theorists 

 in the early fields of American meteorology. Loren Blodgett, 

 M. N. I., published in 1857 a work on the climate of the United 

 States, far superior to anything previously sent out. About the 

 time of Redfield's earlier work, Prof. Mitchell, of the University 

 of North Carolina, propounded a theory which seems to have at- 

 tracted but little attention as indeed it deserves but little 

 maintaining that certain storms, especially those of the Atlantic 

 coast, are the result of a gyratory motion about an axis parallel 

 to the plane of the horizon. This proposition he held in opposi- 

 tion to Redfield, whom he mentions as contending for the revolu- 

 tion of the wind about an axis perpendicular to the plane of the 

 horizon. This speculation of Prof. Mitchell was of less value 

 to science than his suggestion of the plan of daily maps, show- 

 ing the aspects of the sky, that cloud boundaries might be 

 traced, and thus their extent and movements discovered an 

 idea which is incorporated into the every-day work of the Sig- 

 nal Service at Washington. Still another of the meteorologists 

 of service in the line of investigation we are describing was 

 Coffin, the author of Studies in the Winds of the Northern Hemi- 

 sphere. 



Dr. Joseph Henry. When the study of the laws of storms 

 and their movements in America had gone as far as this, it had 

 reached a point beyond which it could not proceed without a more 

 abundant material in the way of observations and statistics. 

 More data were required, if larger demonstrations were to be 

 made. The time had come when no great advance in the knowl- 

 edge of storms could be had, unless they were carefully studied 

 over large areas, their actions noted at a great number of points 

 at once, and the information thus gained reduced to order. Of no 

 other science is this so true as of meteorology ; of no branch of 

 meteorology is it so true as the observation of storms. Eternal 

 vigilance is the price of all knowledge in this great field. And 

 we are now at a point in the progress of the study of American 

 storms when a great advance was made. Prof. Joseph Henry, 

 the Director and Secretary of the Smithsonian Institution, and one 



