832 
that they were sent to walk through the land, 
and that they described it in seven parts in a 
book; and Josephus relates that when Joshua 
sent out people from the different tribes to 
measure the land, he gave them as compa- 
nions persons well skilled in geometry, who 
could not be mistaken in the truth. 
The first Grecian map on record was that 
of Anaximander, mentioned by Strabo, sup- 
posed to be that referred to by Hipparchus 
under the designation of the antient map. 
Herodotus minutely describes a map made 
>by Aristagoras, tyrant of Miletus, which will 
serve to give some idea of the maps of those 
times. He relates, that Aristagoras shewed 
it to Cleomenes, king of Sparta, to induce 
him to attack the king of Persia at Susa, in 
order to restore the lonians to their antient 
liberty, it was traced upon brass or copper, 
and seems to have been a mere itinerary, 
containing the route through the interme- 
diate countries which were to be traversed in 
that march, with the rivers Halys, the Eu- 
phrates, and Tigris, which Herodotus men- 
tions as necessary te be crossed in that expe- 
dition. It contained one straight line called 
the royal road, or highway, which took in all 
the stations or places of encampment from 
Sardis toS sa ; being U lin the whole journey, 
and containing 13,500 stadia, or 168/i Roman 
miles of 5000 feet each. 
Eratosthenes first attempted to reduce 
.geography to a regular system, and intro- 
duced a regular parallel of latitude, which 
began at the straits of Gibraltar, passed east- 
wards through the isle of Rhodes, and so on 
to the mountains of India, noting all the in- 
termediate places through which it passed. 
In drawing this line, he was not regulated bv 
the same latitude, but by observing where 
the longest day was 14 hours and a half, 
which Hipparchus afterwards determined was 
the latitude of 36 degrees. 
'[ his first, parallel through Rhodes was ever 
after considered with a degree of preference, 
in constructing all the antient maps; and the 
•longitude of the then known" world was often 
•attempted to be measured in stadia and miles, 
-according to the extent of that line, by many 
•succeeding geographers. 
Eratosthenes soon after attempted not only 
: to draw other parallels of latitude, but also to 
•trace a meridian at right angles to these, 
passing through Rhodes and Alexandria down 
io Syene and Meroe; and at length he un- 
dertook the arduous task of determining the 
■circumference of the globe, by an actual 
measurement of a segment of one of its great 
•circles. To find the magnitude of the earth j 
is indeed a problem which has engaged the ! 
attention of astronomers and geographers j 
ever since the spherical figure of it was j 
known. It seems Anaximander was the first 
among the Greeks who wrote upon this sub- 
ject. Archytas of Tarentum, tt Pythagorean, 
famous for his skill in mathematics and me- 
chanics, also made some attempts in this 
way, and Dr. Long conjectures that these 
are the authors of the most antient opinion 
that the circumference of the earth is 400,000 i 
stadia ; and Archimedes makes mention of the 
antients who estimated the circumference of 
the earth at okIv 30,000 stadia. 
As to the methods of measuring the cir- 
cumference of the earth, it would seem, from j 
wiut Aristotle says in his treatise De Ccelo, ; 
GEOGRAPHY. 
that they were much the same as those used 
by the moderns, deficient only in the accu- 
racy of the instruments. That philosopher 
there says, that different stars pass through 
our zenith, according as our situation is more 
or less northerly; and that in the southern 
parts of the earth stars come above our ho- 
rizon, which are no longer visible if we go 
northward. Hence it appears that there are 
two ways of measuring the circumference of 
the earth ; one by observing stars which pass 
through the zenith of one place, and do not 
passthrough that of another; the other, by 
observing some stars which come above the 
horizon of one place, and are observed at the 
same time to be in the horizon of another. 
The former of these methods, which is the 
best, was followed by Eratosthenes at Alex- 
andria in Egypt, 250 years before Christ. 
He knew that at the summer solstice, the sun 
was vertical to the inhabitants of Syene, a 
town on the confines of Ethiopia, under the 
tropic of Cancer, where they had a well made 
to observe it, at the bottom of which the rays 
of the sun fell perpendicularly the day of the 
summer solstice: he observed by the shadow 
of a wire set perpendicularly in an hemi- 
spherical bason, how far the sun was on that 
day at noon distant from the zenith of Alex- 
andria; when he found that distance was 
equal to the 50th part of a great circle in the 
heavens. Then supposing Syene and Alex- 
andria under the same meridian, he inferred 
that the distance between them was the 50th 
part of a great circle upon the earth ; and 
this distance being by measure 5000 stadia, 
he concluded that the whole circumference 
of the earth was 250,000 Stadia. Rut as this 
number divided by 360 would give 694-^ 
stadia to a degree, either Eratosthenes him- 
self, or some of his followers, assigned the 
round number 700 stadia to a degree, which 
multiplied by 360, makes the circumference 
of the earth 252,000 stadia; whence both 
these measures are given by different authors 
as that of Eratosthenes. 
In the time of Pompey the Great, Posido- 
nius determined the measure of the circum- 
ference of the earth by the 2d method above 
hinted by Aristotle, viz. the horizontal obser- 
vations. Knowing that the star called Ca- 
nopus was but just visible in the horizon of 
Rhodes, and at Alexandria finding its meri- 
dian height was the 48th part of a great 
circle in the heavens, or 1 \ deg., answering 
to the like quantity of a circle on th<* earth ; 
then supposing these two places under the 
same meridian, and the distance between 
them 5000 stadia, the circumference of the 
earth will be 240,000 stadia ; which is the first 
measure of Posidonius. But according to 
Strabo, Posidonius made the measure of the 
earth to be 180,000 stadia, at the rate of 500 
stadia to a degree. The reason of this differ- 
ence is thought to be, that Eratosthenes mea- 
sured the distance between Rhodes and Alex- 
andria, and found it only 3750 stadia; taking 
this for a 48th part of the earth’s circumfer- 
ence, which is the measure of Posidonius, 
tlie w hole circumference will be 180,000 
stadia. This measure was received by Ma- 
rinas of Tyre, and is usually ascribed to Pto- 
lemy. Rut this measurement is subject to 
great uncertainty, both on account of the 
great refraction of the stars near the horizon, 
the difficulty of measuring the distance at sea 
between Rhodes and Alexandria, and by sup- 
posing those places under the same 'meridian, 
when they are really very different. 
Several geographers afterwards made use 
of the different heights of the pole in distant 
places under the same meridian, to find the 
dimensions of the earth. About the yesfr 
800 the khalif Almemun had tiie distance 
measured between two places that were two 
degrees asunder, and under the same meridian, 
in the plains of Sinjar in the Red Sea ; and 
the result was, that the degree at one time, 
was found equal to 56 miles, and at another 
56j or 56y miles. 
The next attempt to find out the circum- 
ference of the earth was in 1525, by Ferne- 
lius, a learned philosopher of France. For 
this purpose he took the height of the pole 
at Paris, going thence directly northwards, 
till he came to the place where the height of 
the pole was one degree more than at that 
city. The length of the way was measured 
by the number of revolutions made by one of 
the wheels of his carriage ; and after proper 
allowances for the declivities and turnings of 
the road, he concluded that 68 Italian miles 
were equal to a degree of the earth. 
According to these methods many other 
measurements of the earth’s circumference 
have since that time been made, with much 
greater accuracy : a particular account of 
which is given under the article Degree. 
Though the maps of Eratosthenes were the 
best of his time, they were yet very imper- 
fect and inaccurate. " They contained little 
more than the states of Greece, and the do- 
minions of the successors of Alexander, di- 
gested according to the surveys above-men- 
tioned. He had indeed seen, and has quot- 
ed, the voyages of Pythias into the great 
Atlantic ocean, which gave him some faint 
ideas of the western parts of Europe; but so 
imperfect, that they could not be realized 
into the outlines of a chart. Strabo says he 
was very ignorant of Gaul, Spain, Germany, 
and Britain; and he was equally ignorant of 
Italy, the coast of the Adriatic, Pontus, and 
all the countries towards the north. 
Such was the state of geography, and the 
nature of the maps, before the time of Hip- 
parchus. lie made a closer connection be- 
tween geography and astronomy, by deter- 
mining the latitudes and longitudes from ce- 
lestial observations. 
War has usually been the occasion of mak- 
ing or improving the maps of countries; and 
accordingly geography made great advances 
from the progress of the Roman arms. In all 
the provinces occupied by that people, camps 
were every where constructed at proper in- 
tervals, and good roads made for communi- 
cation between them; and thus civilization 
and surveying were carried on according to 
system through the whole extent of that large 
empire. Every new war produced a new sur- 
vey and itinerary of the countries where the 
scenes of action passed; so that the materials 
of geography were accumulated by every 
additional conquest. Polybius savs, that at 
the beginning of the second Punic ’war, when 
Hannibal was preparing his expedition against 
Rome, the countries through which he was 
to pass were carefully measured by the Ro- 
mans. And Julius Cxsar caused a general 
survey of the Roman empire to be made, by 
a decree of the senate. Three surveyors 
had this task assigned them, which they coin 
pleted in 25 years. The Roman itineraries 
