the measure of any thing from the surface downwards.

Measuring of Depths by the Barometer, depends on the same principles on which heights are measured by the same instrument. The mensuration of depths being Depuration chiefly applied to mines, is still more precarious than the mensuration of heights, on account of the various kinds of vapours with which these subterranean regions are filled. But for a particular account of these difficulties, with the best methods of obviating them, see the articles Barometer and Mines.

Depth of a Squadron, or Battalion, is the number of men in a file; which in a squadron is three, and in a battalion generally six. See Squadron, File, &c.

We say, the battalion was drawn up five deep; the enemies horse were drawn up five deep.