A T L 



JO 



A T M 



Arlu. 



eruptions. Whitehurst 13 of opinion, that the At- 

 lantic island of Plato, was probably the portion of 

 land which, stretching from the north of Ireland, ex- 

 tended to the Azores, and from the Azores to the 

 continent of America. He thinks that the Giant's 

 Causeway, and the abrupt cliffs which environ part of 

 Mantic ocean, are a sufficient demonstration, 

 that some violent disruption of the earth has taken 

 place in that quarter at some remote period of the 

 world. We shall let him speak for himself on this 

 subject. 



" These circumstances render it necessary to ob- 

 th*t whosoever attentively views and considers 

 these romantic rocks, together with the exterior ap- 

 pearances of that mountainous cliff, will, I presume, 

 soon discover sufficient cause to conclude, that the 

 crater, from whence that melted matter flowed, to- 

 gether with an immense tract of land towards the 

 north, have been absolutely sunk and swallowed up 

 into the earth, at some remote period of time, and be- 

 came the bottom of the Atlantic ocean : A period 

 indeed much beyond the reach of any historical mo- 

 nument, or even of tradition itself. But though it 

 does not appear, that any human testimony, or record, 

 has been handed down to us concerning such a tre- 

 mendous event, yet the history of that fatal catas- 

 trophe is faithfully recorded in the book of nature, and 

 in language and characters equally intelligible to all 

 nations, and therefore will not admit of a misinterpre- 

 tation ; I mean the range of lofty abrupt cliff's which 

 environs a part of the Atlantic ocean. 



These are characters which cannot mislead, or di- 

 vert our attention from the true cause thereof; and 

 we may further add, as a collateral testimony, that 

 subterraneous fires have frequently burst open the 

 bottom of that ocean in various parts, and have form- 

 ed new islands of considerable magnitude ; whence it 

 is evident that the same cause still exists, and produces 

 similar effects. I say, the consideration of such dis- 

 asters, together with that of the causes still subsisting 

 under the bottom of that immense ocean, almost per- 

 suade me to conclude, that Ireland was originally a 

 part of the island Atlantis, which, according to Pla- 

 to's Timaeus, was totally swallowed up by a prodi- 

 gious earthquake, in the space of one day and night, 

 with all its inhabitants, and a numerous host of war- 

 like people, who had subdued a considerable part of 

 the known world." See the Timceus of Plato. Un. 

 Hi<t. vol. xviii. p. '250. Buffon's Nat. Hist, vol. ix. 

 p. 102. Whitehurst's Inquiry, p. 258. Maurice's 

 Hist, of Hindustan, vol. i. p. 538. (g) 



ATLAS, a chain of mountains in the north-west 

 f Africa, called in the Arabic Jibbel Atlils, or the 

 Mou>itains of ' Snoxc. This chain of mountains is in- 

 habited by the various tribes of Berebbers, and ex- 

 tends from (Jibbel d'Zatute) Ape's Hill on the 

 Mediterranean to Shtuka andAit Bamaran in Lower 

 Suse, passing at the distance of 30 miles to the east 

 of Morocco, where they are of an immense height, 

 and covered with eternal snow. This part of the 

 range appears in a clear day like a saddle when seen 

 from Mogodor, a distance of 140 miles, and it is visi- 

 ble at sea to vessels several leagues off the coast. These 

 mountains, though extremely cold in winter, are sa- 

 lubrious and pleasant. The vallies are well cultivated, 

 3 



and the mountains having the advantage of various 

 climates, abound in excellent fruits, and extensive 

 The contrast between their snowy summits 

 and the rich verdure below, gradually decaying as it 

 approaches the limit of congelation, has a very singu- 

 lar and picturesque appearance. In the part of the 

 great chain which pay. s by Morocco to the east 

 there are excellent mines of copper, and the branches 

 which traverse the district of Suse produce silver, cop- 

 per, iron, lead, and sulphur of saltpetre. They have 

 also mines of gold mixed with antimony and lead ore. 

 According to the Moors, there are many quarries of 

 marble granite, and other valuable rocks in this ex- 

 tensive range. The Berebbers, v ho inhabit tne up- 

 per regions of Atlas, live from November to February 

 inclusive in excavations in the mountains. See Pliny, 

 lib. v. cap. 1 ; Slrabo, lib. xvn; Shaw's Travels in 

 Barbary, p. 5 ; Lempricre's Journey to Morocco, 

 p. 15 ; Chenier's Present State of Morocco, vol. i. 

 p. 13; Pmkerton's Geography, vol. lii. p. 815; 

 but particularly Jackson's Account oj the Empire of' 

 Morocco, 1809, p. 10. (o) 



ATLAS, tlie name of that joint or vertebra of the 

 neck which is nearest the head. See Anatomy, (iv) 

 ATMOMETEll, Atmimmbhb, or Atmedo- 

 metek, from xTfus, vapour, and jmstv, a measure, 

 the name given to an instrument for measuring eva- 

 poration. An ingenious instrument of this kind has 

 been described by the celebrated Professor Richman, 

 in the Nov. Comment. Petropol. vol. ii. p. 121. (w) 

 ATMOSPHERE, that invisible elastic fluid which 

 surrounds the earth, and encloses it on all sides. It 

 received its name from the Greeks, in consequence of 

 the vapours which are continually mixing with it. 

 The ancients considered it as one of the four elements 

 of which all things were composed, and some of them 

 seem to have thought that it enters as a constituent 

 principle into other bodies, or at least that air and 

 other bodies are mutually convertible into each other. 

 [l.ucret. lib. v. 274.) No experiments on its na- 

 ture could well be made by the ancients, as they were 

 unprovided with every instrument fitted for such in- 

 vestigations, and unacquainted with the principles 

 upon which their construction depended. But it has 

 occupied a great deal of the attention of modern phi- 

 losophers, and has given birth to some of the most 

 brilliant discoveries that grace the annals of science. 

 Its weight was first ascertained by Galileo, and ap- 

 plied by Torricclli to explain the rise of water in 

 pumps, and of mercury in barometrical tubes, and by 

 Paschal to the mensuration of the height of moun- 

 tains. Its elasticity was accurately determined by 

 Boyle, who may be considered as in some measure 

 the founder of the science of pneumatics. Halley 

 and Newton explained the effects produced on it by 

 moisture. Hooke, Newton, Boyle, Derham, point- 

 ed out its relation to light, to sound, and to electri- 

 city. Its effect upon combustibles and animals was 

 investigated by Boyle, Hooke, Mayow, Hales, Priest- 

 ley, Sch vie, and Lavoisier. Its constituents were 

 defected and measured by the experiments of Priest- 

 ley, Scheele, Lavoisier, and Cavendish. The effect 

 of heat on it was determined by Shuckburgh,Dalton, 

 and Gay Lussac. But it would be an endless task 

 to enumerate all the philosophers who have distin- 



Atlat 



I 



Atmo- 

 sphere. 



