T RAV

60 TRAVELS JNEUR@iPE.trutl1; certain]}' enough 80 to give a goodgeneral idea of itsheight.The fise of the surface, inland, upon twenty geographical m.iles, wherethe waters are torrents, canBot do rnuch less th~tncorrljspond with theirpart of the computation; and Minorca, eighty miles distant, ia Witft~Bthe horizon, for the firing at the last siege iQ that island was distinguishableat night from these pinnades, as the hermits assure us:t-.C..r ALONIA ,vas once a plain, nearly From the centre whereofeluel"gesthl$ !3tupendolls and insulated mass; immlated asmucb in point .ofcpmposition as of elevation. Its forJl:Lisoval; perhaps in the proportionof ahout three t two. !ts hlngeat diameter ia probably aboutquadruple its elevation. $upposing this. diameter taken at the b.ase ofthe perpendicular peakst; that is to say, at the height of about tw.'" "The Balearic Isles (one hundred and eighty miles distant) are visible j'rom tlle eonveTft/"­Bpitome Historieo.t Il person on aBat shore or place but a little above thelevel of the séS, and seéing, by means~f a telescope, the vane of a ship QJ; top of a mountain of a known altitude, may, by the followingrule, tell the distance. Or, vice versa, a person on the top of a mountain, seeing from it an objectRt a known distl,l.nce not much above the level of the sea, may ascel'tain by it the height of the"Qunt~in.RULE.To the diam~ter of the earth add the height of the eye; multiply th,e sum by this height, an9thesquare root ofthe produet is the distance, ifthe height of the eyebe givcn or known. Or ifthed~~aneehe givetl or known, it:s sql.l,are is equal ta the rli\etangle under the diameter of the earth,and the height of the eye taken together b.y the said height of the eye, or to the .:product of thediameter of the earth and height of the eye by the said height of the eye.!iI'he diamèter ofthe earth is v(\ry nearly equal to 1,924 English miles, which maybe: reprœentedbr 2d. L~ the distance be denoted b~ s, and the height of the eye by k.Then the eqg,atiQu 'villhe 2dh+h 2 =S2; from which, when h is given, we have s= .v 2Jh+h 2 ,aud when s is gtven Wf;Jlget h S +2dh+d'=s'+d' and h=vs'+d 1 -d. This general expression will give the heightofthe pinuades Qf Mon.t~errat above the l\1:editer;anean (if Minorca he in the verge of theil' hori~QJ)and 80 miles distant)., about l~or 8-tenths nearly ofan English mile iif 70 mil~s distaut?ahout3,168 Englïsh feet ~ 6nq,if 6Q ~il~& dj~ta't,; ~o;;t.lt ~.t3;& ~1ili~b fee~.~.(i.