G E O G R 
F^tei’ Petit, a mathematician of fome eminence in 
Trance, endeavoured to revive this opinion in a diflerta- 
tion publiflied in 1660, from the apparent variations in 
the latitude of Paris, as taken by the ableit aftronomers, 
fonie of whom had made it 48® 39', others 48° 45', fome- 
times 4^,° 50’, and at other times 48® 55'. All of which 
only conhrms an obfervation made by an eminent French 
aftronomer, that they had no good quadrant fit for tak¬ 
ing an obfervation of the latitude, even in the whole 
kingdom of France, in the year 1664. For M. Auzot, 
in a letter which he addrelfed to Louis XIV. in this very 
year, made ufe of the following words : Mat's^ Jire, c'ejl 
un malht.vr, qu'il n'y a pas v.n injlrunient a Paris^ ni^ que je 
ffache, dans tout votre royauvie^ avquel je vcmlvjft m’a^urer 
pour prendre precifement la hauteur du pole. 
The latitude of London was known much fooncr than 
chat of Paris, and brought to a greater degree of accuracy; 
for it w'as determined by Edward Wright, who is other- 
wife diflinguiflied as the original inventor of what is 
called Mercator's Chart, by obfervations made in 1593 and 
1594, from the greateft and leaft height of the polcftar, 
and found to be 51° 32', taken by a brafs quadrant of fix 
feet radius; before that time the latitude of London 
was fuppofed to be 51® 43' In all the maps of that age. 
And though this obfervation was made at a time when 
the error from refraction had been juii; difeovered by 
Tycho, and not fully known, yet it is allowed to be juft 
and exaCl even now, when the inftriiments which are 
conftruCted at prefent enable obfervers to come to the 
Utmofl: precifson of I'econds. 
There is another particular hitherto unnoticed, which 
has greatly contributed to the folid advancement both 
of aftronomy and geography, and this is the more accu¬ 
rate method now prattifed for the meafuring of time, 
which though in appearance of a different nature, is 
equally capable of being applied to the menfuration of 
fpace. For irt the tables of longitude it is well known 
that time and fpace are ufed like two different languages, 
where the fame truth is expreifed with equal clearnefs 
in both, though in characters that are eii'entially differ¬ 
ent from each other; as one hour in time is allowed to 
be equal to fifteen degrees in fpace upon the furface of 
the earth, and of courfe all the aliquot parts of each 
are in the fame proportion. Sun-dials, and clepfydrx, 
or water-clocks, were the principal nieafurers of time 
among the ancients. It was only about the year of 
Chrift 1300, that clocks with indented wheels are laid 
to have been firft in ufe; and it was not till two hiinr 
dred years after this that they feein to have been em¬ 
ployed for the purpofes of aftronomy. For Waltheriis, 
the difciple of Regiomontanus, is laid to have had one 
about the year 15005 which Schoner, who publiflied 
bis obfervations in 1544, fays, was lb regular, that from 
niid-day to mid-day it perfectly agreed with the fun, 
and was aliiioft as exaCt m the times given, as in thofe 
drawn from calculation. Tycho Brahe is faid to have 
had four decks which marked minutes and feconds, 
the iargeft of wiiich had only three wheels 5 the dia¬ 
meter of one of them was three feet, and it had 1200 
teeth. BiU all of thole were exceedingly imperfeCt, 
till M. Huyghens improved them in 1656, by his inven¬ 
tion and application of the peiiduiuni, wliofe vibrations 
were regular and ifochronical. The improvements that 
have been ruice made in time-pieces, and the manner in 
which they have been applied to tlie determination of 
longitude, is a branch of knowledge of the utmoll iin- 
poi tance to geography and navigation. 
Thefe advantages, however, and many other acquifi- 
tions derived from mathem«tical geography, were not 
fo compKtely underltood, till the voyages of Magellan,. 
Drake, ai»d Cook, round the world, and the great ex- 
tenlion of commerce, impelled the learned to call forth 
their ablelt exertions, 'i'he autliors moft diftinguilhed 
for their, works in this department are, Cluverius, Heid- 
•mann, Janion, Cellarius, Sxhwarjz, hXaj).uert, goghart, 
4 
A P H Y. a47 
and Michaelis ; the two Bienewitz, Munfter, Gemma, 
Mercator, and others, of tlie lixteenth century, have 
alfo in this refpeCt confiderable merit. In the eighteent h 
century, by the meafurement of a degree at the pol ar 
circle, and on the equator, the French were enabled ta 
afeertaia the real■ form of the earth ; and fimilar mea- 
furements have fince been made by the Englilh and Ger¬ 
mans, The principal mathematical geographers of tliis 
period were Picard, Sturm, Caflini, Kraft, Maupertuis, 
Clairautj.Le Monnier, Bouguer, Condamiae, Bofeo- 
wich, Frifi, Mafon, De la Laade, De la Place, Klugel, 
Bode, Kloftermann, and Zach. Belides thefe, we have 
others more remote, fuch as Edrefi, a learned Moham¬ 
medan of Cordua; the bell tranflation of whole work 
was publiflied by Hartmann at Gottingen, in 1796 ; 
Abdollatif Ibn-Jufuph of Bagdad, whofe Compendi¬ 
um, &c, was publilhed by Dr, White in Arabic, with a 
preface by Paulus, in 1789, and tranllated into German 
by Wahl in 1790 j Abulfeda, whofe works have been 
at different times, and in parts, edited by Reilke, Grsi- 
vius, Koehler, Michaelis, andEichhorn; Benjamin of 
Tudela, a travelling Jew, whofe itinerary was firft pub¬ 
liflied by I’Empereur, in 1633, and has fince been tranf- 
lated into French by Barratier, and into Englilh by 
Gewans. Mercator’s fyftem of projeftion now became 
the grand foundation for the improvement of modern maps 
and charts. He was followed, in the feventeenth cen¬ 
tury, by Hond, Munfter, Sanlbn, and others. The am- 
pleft ftrides, however, towards perfedtion, have been 
made in the eighteenth century by De I’llle, d’Anville, 
Goffelin, and others, of the'French ; by Jefferys, Faden, 
Rennell, Arrowfmith, and others, of the Englilh ; by 
Schmidt, Glifleman, &c, of the Germans; and by va¬ 
rious others. In the department of phyficai geography 
we are much indebted to the labours of SiiHiniich, Lu- 
lof, Bergman, Wallerius, Haidinger, Forfter, De Luc, 
Pallas, Dolomieu, Zimmermann, Meierftto, Otto, and 
other ingenious philofophers. 
Among the mifcellaneous authors who have contri, 
bated to the illiiftration of geography, are Johannes de 
Sacrobofeo, or John Hallifax, who wrote a treatife on 
the fphere ; Clavius, on the fphere of Sacrobofeo 5 
Piccioli’s S Hydrographia Reformata-, Weige. 
lius’s. Terra:-, De Chales’s Geography, in his, 
Mundus Mathematicus ; Leibnecht’s Elementa Geographic ge„ 
neralis ; Stevenius’s Compendium Geographicum Wolfius’s, 
Geographia, in his Elementa Mathejeos ; Bufehing’s 
Syltem of Geograpliy; Gordon’s, Salmon’s, and Gii- 
thrie’s, Grammars; Varennius’s Geographia gmtralis, 
with Jurin’s additions; and Pinkerton’s Modern Geo¬ 
graphy, the moft fyftematic and perfect of this ciafs. 
Of practical GEOGRAPHY. 
. The fundamental principles of geography are only tq 
be acquired by an- intimate knowledge of that depart¬ 
ment of the fcience, which is termed mathematical or coj- 
mosraphical geography ; becaul'e it teaches the mechani¬ 
cal conftrultion of the univerfe, connedU the aftrone- 
niical with the geographical circles of the fphere, exhi¬ 
bits the feveral divsiions of the earth and heavens on a 
plane, and furniflies to the mind’s eye a comprehenfive 
view of the world, witlioiit the labour of travel : 
whence is derived tlie artificial conftriiition of globes, 
the projection of charts and maps, with all the inftru- 
ments that are fubfervient to our refearches in aftrono- 
mical and geographical fcience. 
The piincipa! terrellrial phenomena, with wliich it Is 
necelfary for the young ftudent to be acquainted, arlfe’ 
chiefly from tlie fphcrical figure of the earth conlidercd 
as a planet, and the polition of its axis with relation t<0 
the fun ; particularly the riling and letting of the ce- 
leltial luminaries, the length of the days and nights, 
tlie variation of climates, the Icafons of the year, &ci 
all of which are amply explained under the tu'tiek 
A§XK,0|<9J4Y, Y@l. ii. p. 3^1-374; yet ftill it helongfi 
cl' 
