This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
The form of the axe handle deserves notice, differing as it does from that of the sledge hammer. In the latter, it is round or nearly so; in the axe, it is oval, the narrow end of the oval being on the side towards the edge of the axe, and, more than this, the longer axis of the oval increases as the handle approaches the head, till at its entrance into the head it may be double what it is at the other extremity. It often has also a projection at the extremity of the handle. The increasing thickness near the head not only gives strength where needed, as the axe is being driven in, but it also supplies that for which our ancestors employed thongs, viz. assistance to the strain necessary to release the blade from the cut. There is, too, this further difference - in a sledge hammer more or less recoil has to be provided for, and the handle does this; in the axe no recoil ought to take place. The entrance of the axe edge is, or ought to be, sufficient to retain it, and the whole of the energy resulting from muscular action and gravity should be utilized. The curvature, too, of the handle is in marked contrast with the straight line of the sledge hammer handle. The object of this curvature is worthy of note. In the American forester's axe, the handle is very long and curved.
If laying the axe handle across the finger where the head and handle balance, the blade of the axe is placed horizontal, the edge does not turn downwards: in fact, the centre of gravity of the axe head is in the horizontal straight line prolongation of the handle through the place where the finger is. Now in sledge hammer -work the face is to be brought down flat, i.e. as a rule, in a horizontal plane. With the foresters' axe, it has to be brought down at varying obliquities. If the hewer's hand had to be counteracting the influence of gravity, there would be added to him very needless labour, hence the care of a skilled forester in the balance of the axe-head and the curvature of the handle.