AMP 



AMP 



rate climates, most of the Amphibia pass 

 the winter in a torpid state ; and that 

 sometimes ia a degree of cold which 

 would seem but ill calculated for the pre- 

 servation of animal life. The common 

 large water-newt, in particular, is said to 

 have been occasionally found completely 

 embedded in large masses of ice, in which 

 it must have remained inclosed for a very 

 considerable period; and yet, on the dis- 

 solution of the ice, has been restored to 

 life. The Amphibia may be divided into 

 four distributions, viz. Testudmes, Ranae, 

 Lacertse, and Serpentes; or Tortoises, 

 Frogs, Lizards, and Serpents. The ani- 

 mals belonging to the three former of 

 these divisions constitute the order enti- 

 tled Reptilia, containing the Amphibia 

 Pedata, or Footed Amphibia. The last 

 division, or that of Serpents, constitutes 

 the order Serpentes ; containing the Am- 

 phibia Apoda, or Footless Amphibia. 



AMPHITRITE, a genus of worms, of 

 the order Molusca; body projecting from 

 a tube, and annulate ; peduncles or feet 

 small, numerous ; feelers two, approxi- 

 mate, feathered; no eyes. There are seven 

 species: of which the A. renifurmis, with 

 a rounded body and simple feelers, is 

 three inches long, and inhabits the seas 

 about Iceland. The body is of a most 

 beautiful red ; head defended by two 

 semicircular arches; plumes fourteen, and 

 alternately red and white ; annulations of 

 the body from 80 to 90, with each a mi- 

 nute tubercle on each side ; tail pointed, 

 and not jointed; tube red, tough, cori- 

 aceous, simple, and four inches long. 



AMPH1SBJHNA, in natural history, a 

 genus of Serpents, of which the generic 

 character is, body cylindric, equal; an- 

 nular divisions on body and tail. Accord- 

 ing to Gmelin there are five species ; but 

 Dr. Shaw mentions two only, viz. the Alba 

 and the Fuliginosa. The whole genus is 

 allied to that of the Anguis, and in some 

 degree to the Lacerta : it is, however, 

 readily distinguished by the manner in 

 which the exterior surface of its skin is 

 marked in well-defined numerous circles 

 or rings, completely surrounding, the 

 body, and divided in a longitudinal direc- 

 tion by still more numerous straight lines, 

 thus forming so many square or parrallelo- 

 gramic scales. The alba is about 18 or 

 20^ inches long, and of a proportional 

 thickness. The head, which is covered 

 with large scales, being but little larger 

 in diameter than the body ; the tail is 

 short, terminating in a rounded extremity. 

 The colour is, as the name imports, white, 

 though in some instances it is tinged with 



a pale rose colour. The usual number of 

 circles in this snake is about 223 on 

 the body, and 16 on the tail. It is a na- 

 tive of South-America, where it is found 

 in woods, preying on insects and worms. 

 It is a harmless animal; but on being 

 handled, it excites a slight itching on the 

 skin, accompanied by small pustules, 

 owing to an acrimonious moisture ex- 

 uding from the animal. A. fuliginosa is 

 at all times readily distinguished by its 

 colours. There are about 230 rings on 

 its body and tail. It is white, variegated 

 with black or deep brown spots. The 

 head is without spots. It is found in ma- 

 ny parts of South-America, resembling 

 the alba in its manners, and being equally 

 innoxious. The skin of the amphisbiena 

 is remarkably strong and tenacious, and 

 of a smooth or glossy surface : it is sup- 

 posed to be able to perforate the ground 

 with great facility, in the manner of earth 

 worms, to obtain its food. The other 

 species are found in America. See plate 

 Serpentes, fig 2. 



AMPLITUDE, in astronomy, an arch 

 of the horizon intercepted between the 

 east or west point thereof, and the centre 

 of the sun, star, or planet, at its rising 

 and setting, and so is either north or 

 south. 



If the amplitude be taken from the 

 rising sun, or star, it is called its rising 

 or ortive amplitude ; if, when it sets, its 

 setting or occasive amplitude. The sun's 

 amplitude, either rising or setting, is 

 found by the globes, by bringing the sun's 

 place to the horizon, either on the east 

 or west side, and the degrees from the 

 east point, either north or south, are the 

 amplitude required. To find the ampli- 

 tude trigonometrically, say, as the cosine 

 of the latitude : radius : : sine of the pre- 

 sent declination : sine of the amplitude. 

 This problem is useful in navigation, to 

 find the variation of the compass. Thus, 

 in latitude 51 31', when the sun's decli- 

 nation is 23 28', then we say, 



As 60. S. 61 31', : 10. &c. : : S. 28 28' 

 : S. Amp. or, as 9.793990 : 10. &c. : : 

 9.600118 : 9.806127 = sine of 39 47' = 

 the amplitude sought : that is, the suu 

 then rises or sets 39 47' from the east or 

 west point to the north or south, us the 

 declination is either north or south. 



AMPLITUDE, magnetical, the different 

 rising or setting of the sun, from the east 

 or west points of the compass. It is found 

 by observing the sun, at his' rising and 

 setting, by an amplitude compass. The 

 difference between the magneticul ampli- 

 tude and the true amplitude is the vari- 



