In the Reading Prong most of the hills rise 900-1000 ft.
- Lateral metacarpals as in Cervus; antlers large, without a brow-tine or sub-basal snag, dichotomously forked, with the upper prong of the fork curving forwards and dividing, and the lower prong long, simple, and projected backwards, the beam making a very marked angle with the plane of the face; tail very long; vomer as in Capreolus.
The north-east part is a south-westward arm of the New England uplands, is known as the Reading Prong, and extends from New Jersey through Easton to Reading.
Hence when a white line is in a particular position on the cylinder, the prong will always be the same distance along it and cut off the same length from view.
If one prong of each fork be furnished with a small plain mirror, and a beam of light from a luminous point be reflected successively by the two mirrors, so as to form an image on a distinct screen, when one fork alone is put in vibration, the image will move on the screen and be seen as a line of a certain length.