APT 



APT 



ab 



, and 



4- b = a 



"There is a general method of investi- 

 gating the value of such series, for which 

 see SERIES. 



APPULSE, in astronomy, the approach 

 of a planet towards a conjunction with 

 the sun, or any of the fixed stars. The 

 appulses of the planets to the fixed stars 

 have always been of great use to astrono- 

 mers, in order to fix the places of the 

 former. The ancients, wanting an easy 

 method of comparing the planets with 

 the ecliptic, which is not visible, had 

 scarce any other way of fixing their situa- 

 tions, but by observing their tract among 

 the fixed stars, and remarking their ap- 

 pulses to some of those visible points. Dr. 

 Halley has published a method of deter- 

 mining the places of the planets, by ob- 

 serving their near appulses to the fixed 

 stars. 



APPURTENANCES, in common law, 

 signify things corporeal and incorporeal, 

 that appertain to another thing as princi- 

 pal ; as hamlets to a manor, and common 

 of pasture and fishery. Things must agree 

 in nature and quality to be appurtenant, 

 as a turbary, or a seat in a church, to a 

 house. 



APRICOT, in botany, a species of pru- 

 nus, with rosaceous flowers, and a deli- 

 cious fleshy fruit, of a roundish figure. 

 See PRUJTCS. 



APRON, in gunnery, the piece of lead 

 which covers the touch-hole of a cannon. 



The dimensions of aprons are as fol- 

 low : viz. for 42, 32, and 24 pounders, 15 

 inches by 13 ; for 18, 12, and 9 pounders, 

 12 inches by 10 ; and for cannon of less 

 calibre, 10 inches by 8. They are tied by 

 two strings of white marline. 



APSIS, in astronomy, a term used indif- 

 ferently for either of the two points of a 

 planet's orbit, where it is at the greatest 

 or least distance from the sun or earth. 

 Hence the line connecting these points is 

 called the line of the apsides. 



APTENODYTES, in ornithology, pen- 

 guin, a genus of the order Anseres. The 

 bill is straight, rather compressed, and 

 sharp along the edges; the upper mandi- 

 ble is obliquely sulcated, lengthwise ; feet 

 palnuted, shackled ; wings fin-shaped, 

 and without quill-feathers ; feet fettered, 

 four-toed. This genus resembles the alca 

 in colour, food, stupidity, eggs, nes-, po- 

 sitions of legs behind the equilibrium, and 

 consequent erect posture. They are to- 



tally unfit for flight, but swim dexteroush 

 nostrils linear, hid in the groove of the. 

 bill, palate as well as the tongue beset 

 with a few rows of conic, retroflected, 

 stiff papillae ; wings covered with a strong 

 broad membrane ; tail short, wedged, the 

 feathers very rigid. There are nine spe- 

 cies according to Latham, but Gmelin 

 enumerates eleven. 



This genus of birds seems to hold the 

 same place, in the southern parts of the 

 world as the awks do in the northern, 

 and are by no means to be confounded 

 the one with the other, however authors 

 may differ in opinion in respect to this 

 matter. The penguin is seen only in the 

 temperate and frigid zones, on that side of 

 the equator which it frequents ; and the 

 same is observed of the awk in the oppo- 

 site latitudes ; and neither of the genera 

 has yet been observed within the tropics. 

 The awk has true wings and quills, though 

 small; the penguin mere fins only, instead 

 of wings. This last has four toes on each 

 foot ; but the fofmer only three. The 

 penguin, while swimming, sinks quite 

 above the breast ; the head and neck only 

 appearing out of the water, rowing itself 

 along with its finny wings, as with oars ; 

 while the awk, in common with most 

 other birds, swims on the surface. Seve- 

 ral other circumstances peculiar to each 

 might be mentioned ; but we trust the 

 above will prove fully sufficient to charac- 

 terize this genus. The bodies of the pen- 

 guin tribe are commonly so well and 

 closely covered with feathers, that no wet 

 can penetrate ; and as they are in general 

 excessively fat, these circumstances unit- 

 ed secure them from the cold. They have 

 often been found above seven hundred 

 leagues from land ; and frequently on the 

 mountains of ice, on which they seem to 

 ascend without difficulty, as the soles of 

 their feet are very rough, and suited to 

 the purpose. 



Aptenodytes antarctica, is full 25 inches 

 long, and weighs eleven or twelve pounds: 

 it inhabits the south sea from 48 to the 

 antarctic circle, and is frequently found 

 on the ice mountains and islands on which 

 it ascends. It is a numerous tribe ; and 

 they were found in great plenty in the 

 Isle of Desolation. 



The black-footed penguin is found in 

 the neighbourhood of the Cape of Good 

 Hope, but particularly in Robbean or Pen- 

 guin Isles, near Saldanic Bay. Like all the 

 genus, this is an excellent swimmer and 

 diver; but hops and flutters in a strange 

 and aukward manner on the land, and, if 

 hurried, stumbles perpetually ; and fre- 

 quently runs for some distance like a qua- 



