ADA 



mentioned. He refided fome years at Paris, and died there 

 in 1759. Gen. Biog. 



A A M of Franltfurt. See E L s h r. i M F. r. 



Adam, Rorkrt, an eminent architect, was born in 

 172t!, at KIrkaldy, in FifcOiirc, and ediurited in thi; iini- 

 verlity of Edinburgh. Upon his return from Italy, in 

 1762, he was appointed arehitedl to his inaieily, but re- 

 figjied this office in 176^*, on being ekitcd to rtprefcnt the 

 county of Kinrofs in parhament. The geniu'i of jNlr. Adam 

 extended itfelf beyoiid the decorations of buildings, to vari- 

 ous branches of manufacture ; and befidea the improvements 

 which he introduced into th: arehitcAure of the countiv, 

 he difplayfd great (kill and tafte in his numerous drawings 

 in landfcape. Such were his alTiduity and aftivity, that in 

 the year preceding his deathj he deligned eight pubhc, and 

 tu'enty-iive private buildings. The new univerfity of Edin- 

 burgh, and many other confiderable edifices were crefted 

 from his deiigns, and under his direftion ; and they are lad- 

 ing monuments of his diil.i;!guiflied talents in the line of his 

 profeihon. He died Marcli 3, 179Z, and his remains were 

 interred in the fouth aifle of Wcilmiafter Abbey. His bro- 

 ther, James Adam, who died, October 20, 1 794, was alfo 

 eminent as an arcliitefl; ; and his abilities are apparent in the 

 Adelphi buildings, and Portland place, in L,ondo;i. 



Adam, in Geo-^rapi:y, a town of European Turkey, in 

 IN'Ioldavia, ten miles north-north-well of Galatz. 



Adam, or Adom, in jincient Geography, a town of Per^a, 

 on the banks of Jordan, vvhere the river liegan to be dried 

 up for the paiTage of the Ifraelites over againit Jericho. 

 Jofliua, ch. iii. 16. 



Adam's Apple, in Botany, a fpecies of Citrus. 



Adam's Bridge, or, according to Sir William Jones, 

 Ramos Bridge, in Geography, a ridge of fands and rocks, ex- 

 tending acrofs the north end of Manara gulf, from the 

 idand of that name, on the north -well coaft of Ceylon, to 

 Ramencote, or Ramankoil ifland, oiff Raman point. 



Adam's jVW/c, \v\ Botany. See Yucca. 



ADAr4's Peah, in Geography, a high mountain in the 

 ifland of Ceylon, in the form of a fugar-loaf, and terminat- 

 ing in a circular plain about 2C0 paces in diameter. , The 

 fummit is covered with trees, and interfered with ftreams, 

 and has aifo a deep lake, which fupplies the principal rivers 

 that water the illand. This mountain is feen at the diilance 

 of twenty leagues at fea ; but though its height is confi- 

 derable, it is not equal to that of the Pic of Tcneriife. Lat. 

 S° S'i'- Long. 80° 39'. See Adam. 



AD AM A . See A D M A H . 



Adam a, a high mountain in Abyffinia, being one of the 

 ridges of the range of mountains called Amid Amid. 



ADAMAH, one of the fenced cities belonging to the 

 tribe of Nephtali, mentioned Jofliua xix. 36. and called by 

 the Seventy Armaith, and by the Vulgate Edema. It was 

 alfo called Nec:h. 



ADAMANT, Adam as, \n Natural Hiflory, an ancient 

 name for a precious ftone, by us called a diamond. Ada- 

 ijias is ufed by fome ancient naturallfls for the fpume or 

 fcoria of gold, wliich, not being malleable, is call a«ay. 

 This is particularly'' called Xft^cra aJcstf^ov'ja, and is miftj.ken 

 by Pliny for a gem of that name. Mr. Boyle more parti- 

 cularly gives the denomination adamas lucidus to a diamond' 

 in his poflefllon, which had the property of fhining in the 

 dark, hnce difcovercd. in many others, at leaft when excited 

 byfriition. See Eoyle's v-'orksby Birch, vol. i. p. 452. 796. 



Adamant is alfo ufed for a fpecies of iron, denoting the 

 hardeft, or moft highly tempered part of it. This is lome- 

 times called the adamantine part of iron. 



Adamant is fometimes alfo ufed for the Magnet, or 



ADA 



load-flone ; in which fenfe Skinner tiiinks it may be derived 

 from the French aimant, which lignifies tlie fame. 



ADAMANTII, \n EcclefiaJUcal Hi/lory, a name given 

 by fome Chrillian hiftorians to the followers of Origen, fur- 

 named AJamanlius, on account of liis indefatigable iiiduftry 

 in reading and writing, or the llrcngth and acutenefs of his 

 reafoning, according -..> fome ; or rather, as Heuman fays, 

 becaufc his name wa^i Adamantius ; however, Eiifcbius favs, 

 (lib. vi. cap. 14.) this was a common name given to Ori- 

 gen, without afligning any reafon for it. There was an- 

 other perion named yJdairiarliii:, and mentioned by I .ardner 

 (works. Vol. iv. p. 295.) as the author of a dialogue agaiiilt 

 tiie Marcionites, which he places about the year 330. 



ADAMANTEA, in Mythology, the nurfcof Jupiter 

 in Crete. 



ADAMANTINE SPAR, Spalh adamanlinr.—CmiH- 

 dum. — Nellu corivindum. — TeUa cstivindum. — Corone. — Poti- 

 J'a. Adamatitintis Corundum. Linn. This itone is found either 

 cryftalli/ed or in mafs. When cryftallized its ufiial form 

 is that of a regular heitacdral prifni (CRYSTAi.i.ocRAPHy, 

 plate i. fig. I.) of a rough furface, and but little i xtemal 

 lultre ; this, however, being ineapablt of being fplit in a 

 direction either perpendicular or parallel to its axis, is ob- 

 vioully not tlie primitive cryllalline figure belonging to this 

 fubftance. Cryllals of adamantine fpar are occafionally met 

 with, which, inllead of folid angles at thejunttion of the 

 fides of the prifm with the planes of the extremities, pre- 

 fent alternate ifofceles triangles of diiTercnt fizcs, but all 

 forming foUd angles of 122'^. 34'. with the extre.Tic planej 

 of the ciyllal (fig. 2.): if by following this indication of na- 

 ture we detach fucceffively the cr^-ftailine laminse, we fhail 

 at l;ngth entirely lofe the hexaedral prifm, and (hall have in 

 iis place a rhomboidal parallelepiped (fig. 3.) of wliich the 

 plane angles at the rhombs will be 86"". and 94°. ; the folid 

 angles at the fummit will meafure 84°. 31'. and that at the 

 reunion of the bafe will be 95°. 29'. Alfo, the diameter G H 

 will be to the whole height E F as A B to B F (fig. I.) The 

 parallelepiped thus obtained, can be fplit only, in a diredtion 

 parallel to its faces,and muft therefore always preferve the fame 

 form, which is that of the nucleus or primitive cryftal. In 

 fome inftances the folid angles of the prifin are replaced by 

 ifofceles triangular planes, as in fig. 2. but which form folid 

 angles of 160''. 42'. with the planes of the extremities: 

 hence refidts a new modification which fiiews itfelf in the 

 cryllalline varieties (fig. 4, 5, 6.) A third modification is 

 produced by the gradual decreafe in diameter of the hexae- 

 dral prifm ; the varieties of this clafs are moftly irregular, but 

 fome fpecimeas exhibit a regular truncated hexaedral pyra- 

 mid (fig. 7.). 



Corundum cryflals are procured from China and India ;. 

 tliofe from the latter country are in general the pureil. Of 

 the Indian variety the-' colo-.ir is grey, with fiiades of "rcen 

 and light brown ; its fracture is foliated and fpany, fome- 

 times vitreouv ; its external lullre is cauial, hut gi:nernlly 

 vciy flight, that of its crofs frafture is feeblcj. but whea 

 broken in the direftion of its laminx, it is refplendcnt ; in 

 thin pieces, and at the edges cf the cryllals it is femitran- 

 fparent ; it is brittle, and of fuch great hardnefs as to cut 

 rock-crvllal and moft of the gems. Sp. Grav. from 3. tjjo 

 to 3. 959. The Chinefe variety difieis from the Indian in 

 containing grains of magnetic iron ore dilfeminated through 

 its fubilaiice ; in being generally of a darker colour and 

 having- externally a chatoyant luftre : its fpccific gravity iii 

 rather greater, aod its hardnefs is commonly fomtwhat in- 

 ferior. There are two varieties known of conindum in 

 mafs, that from Bengal is of a purplifh hue, and compart 

 fradturc, fp. gr. 3. 876. It is called by the natives coroiiL ; 



that 



