In the Reading Prong most of the hills rise 900-1000 ft.
On one prong of each fork is fixed a small plane mirror.
His deep chestnut head and throat are diversified on either side by a line of buff, which, springing from the gape, runs upward to the eye, in front of which it forms a fork, one prong passing backward above and the other below, enclosing a dark glossy-green patch, and both losing themselves in the elongated feathers of the hind-head and nape.
Instead of a mirror the second fork carries a bright point on one prong, and the microscope is focused on this.
Let the cylinder be rotated so that each white line moves exactly into the place of the next while the prong moves once in and out.
The energy of this fork with a given amplitude of vibration could be calculated from its dimensions and elasticity, and the amplitude was observed by measuring with a microscope the line into which the image of a starch grain on the prong was drawn by the vibration.
The circuit of the electro-magnet is made and broken by the vibration of the fork in different ways - say, by a wire bridge attached to the lower prong which dips into and lifts out of two mercury cups.
On interposing the hand between the ear and either prong of the fork when in one of those positions, the sound becomes audible, because then one of the two interfering waves is cut off from the ear.
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.
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.
The south-west part is a north-eastern prolongation of the Virginia Piedmont, is known as the Cumberland Prong, and extends N.N.E.
Above the sea and about one-half that height above the surrounding country; in the Cumberland Prong their height increases to the southward until, on the Maryland border, they rise 2100 ft.
Another range of hills, known as the Trenton Prong, extends from the northern suburbs of Philadelphia both westward and southward through Chester, Delaware, Lancaster and York counties, but these rise only 400-600 ft.
In the mountains are elk, puma, lynx, the varying hare and snowshoe rabbit, the yellow-haired porcupine, Fremont's and Bailey's squirrels, the mountain sheep, the four-striped chipmunk, Townsend's spermophile, the prong-horned antelope, the cinnamon pack-rat, grizzly, brown, silvertip and black bears and the wolverine.
Bison no longer roam the plains, and the elk has been driven out; but among the larger mammals still to be found in certain districts are the deer, prong-horn (in small numbers), puma, coyote, timber wolf, lynx (Lynx rufus and Lynx Canadensis) and the black and grizzly bear.
- 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.
- Lateral metacarpals as in Rangifer; antlers very variable in size, forming a marked angle with the plane of the face, without a brow-tine; when consisting of more than a simple prong, dichotomously forked, frequently with a subbasal snag, and always with the lower prong of the fork projected from the front edge of the beam, in @ome cases the lower, in others the upper, and in others both prongs again dividing; tail long; tarsal gland generally present; metatarsal gland very variable, both as regards presence and position; vomer dividing the inner aperture of the nostrils in the skull into two distinct chambers.
Such are the white chrysanthemum-like patches on the rump of the Japanese deer and of the American prong-buck (Antilocapra), and the line of hairs situated in a groove on the loins of the African spring-buck.
5 a curves somewhat forward and again divides at least once; while the hind prong is of great length undivided, and directed backwards in a manner found in no other deer.
The antlers are short, upright and deeply furrowed, the beam forking at about two-thirds of its length, and the upper prong again dividing, thus making three points.
Instead of a mirror, the objective of a microscope is attached to one prong of the first fork and the eyepiece of the microscope is fixed behind the fork.
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.
- Antlers large and complex, without a sub-basal snag, and the upper prong more developed than the lower one; metatarsal gland absent; tail short; face moderately long; face-gland and gland-pit well developed; upper canines usually present in male.
- Lateral metacarpals as in Rangifer; antlers rather small, without a brow-tine or sub-basal snag, dichotomously forked, with the upper or posterior prong again forking; tail rudimentary; vomer not dividing posterior nasal aperture of skull.