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This view of Prof. Blasius coincides with that of Sir William Herschel, who says:

—But leaving methods and passing to results, our author defines a storm in general to be "the movement of the air caused by its tendency to reëstablish an equilibrium which has been disturbed; and we may call all such movements storms, whether they are gentle breezes or furious hurricanes, whether accompanied by more or less condensation of moisture or clouds, or even by none at all," as in deserts.

—As the result of his investigations in aerial movements in the northern hemisphere, Prof. Blasius presents the following classification of all storms:

In order that the significance of the above classification may be clearly understood, it will be well to notice in brief outline the general movements of the atmosphere surrounding the globe, more especially those in the northern hemisphere.