MER 
long. It is common in the northern regions 
of Europe and Asia, and is found in tlie 
Oi'kiiies during the whole year. It builds 
sometimes on 'trees, but generally in the 
holes and fissures of rocks, and feeds on 
fish. Its flesh is strong, and seldom applied 
for food. See Aves, Plate IX. fig. 5. The 
M. serrater, or red-breasted goosander, is 
considerably less than the foi mer, is found 
also in tlie same latitudes, and breeds in 
the north of Scotland, particularly in Loch 
Mari, in the oounty of Ross. It dives ex- 
cellently, and is extremely alert on the wa- 
ter. About the season of its moulting, 
however, the natives of Greenland often 
kill it by darts, as the birds are less active 
than usual in that state of weakness, and 
suffer file enemy to approach more nearly 
than at other times. These, birds, like the 
former, and indeed tlie other species of the 
genus, subsist in a great degree on fish. 
They fly near the surface of the water, with 
great apparent vigour, though seldom to 
any great distance. Their sharp, serrated, 
and hooked bills are admirably adapted to 
secure their prey, which is scarcely ever 
observed, notwithstanding all its lubricity, 
to elude their grasp. See Aves, Plate IX. 
fig. 4. Bor the Smew, see Aves, Plate IX. 
fig. 6. 
MERIDIAN, in astronomy, a great cir- 
cle passing through the poles of the world, 
and both the zenith and nadir, crosses the 
equinoctial at right angles, and divides the 
sphere into two hemispheres, the eastern 
and western : it has its poles in the east and 
west points of the horizon. It is called 
meridian, because when the sun cometh 
to the south part of this circle, it is then 
mid-day ; and then the sun has his greatest 
altitude for that day. These meridians are 
various, and change according to the lon- 
gitudes of places ; so that they may be said 
to be infinite in number, for all places from 
east to west have their several meridians : 
but there is (or should be) one fixed, which 
is called the first meridian. Ptolemy chose 
to make that the first meridian whicli passes 
near the Fortunate Islands, at about the dis- 
tiince of one degree from them ; and reck- 
ons from thence to the east through Africa 
and Asia; choosing to begin at a place in- 
habited, and which was then t!ie bounds 
and limits of the known part of the earth 
to the west, and to end at the eastern shore 
of Scain in Asia; but America being dis- 
covered not many ages ago, and long after 
Ptolemy’s time, the first meridian was re- 
moved more to the west. Some made that 
MER 
the first meridian which passes through the 
isle of St. N icholas, which is one of those 
near Cape Verd ; and Hondius chose the 
isle of St. James to be tlie first in his map. 
Others chose that which passes through 
the isle del Corvo, one of the Azores, be- 
cause the needle was found not to decline 
from the north there and in the adjacent 
seas, but to lie in the meridian line ; and 
this beginning Mercator chooses. But see- 
ing there are other places where the needle 
points to the north, and it doth not so in 
every part of that meridian, geographers 
thought this not a sufficient reason ; some 
fixing it at the shore of Brasil, that runs out 
into the sea. Later geographers choose to 
begin at the mountain Teneriffe, in the For- 
tunate or Canary islands, which is counted 
one of the highest on the earth ; and the 
rather, because they thought some remark- 
able place should be chosen tfiat might be 
mo.st known to future ages; and so Ptole- 
my’s first meridian, though long observed, 
was not laid aside without good reason. 
The French, since the year 1634, have 
taken that which goes through the west 
part of tlie isle of Faro, one of the Cana- 
ries. Astronomers also have taken divers 
places for the first meridian ; the followers 
of Tycho fix it at Uraniburg, an island in 
the. Danish streights, and calculate the ce- 
lestial motions to that place, and from 
thence accommodate them to the rest. 
Others choose other places, according to 
the authors of the ephemeris they use, who 
calculate the ephemeris, and the planets 
places for the meridian of their own place ; 
as Riccioli, who fixed his first meridian at 
Bologna ; Mr. Flamsteed, at the Royal Ob- 
rervatory at Greenwich ; and the French, 
at the Observatory at Paris. See Obser- 
vatory. But without regard to any of 
these rules, our geographers and map-mak- 
ers frequently assume the meridian of the 
place, or the capital of the country, for 
the first meridian ; and thence reckon the 
longitudes of their places. 
In the Philosophical Transactions, there 
is a suggestion that the meridians vary in 
time. This seems very probable from the 
old meridian line in the church of St. Pe- 
tronio at Bologna, which is found to vary 
no less than eight degrees from the true 
meridian of that place at this time ; and 
from that of ’lycho Brahe at Uraniburg, 
which M. Picart observes varies eighteen 
minutes from the modern meridian. If 
there be any thing of truth in this hint. Dr. 
Wallis says, the change must arise flora a 
