,'tliat in winter1, when the W c u r y in the barometer de-
f ei ds, the cold increafe ^ ^
344. Land is capable-bf receiving much ‘-m'dreteither
’ heat or cold, than water.- 'f in winter when thefurfaceof
•water i^ much cobled bjsconuft with the'colder air, the
• deeperland warmer water a t : the hottom. ^beih’g fpecifi-
, cally lighter, raes and tempers the' top, and as the
colder water coh ftk r% defcends during the winter, in
• 'th e ' foHowingfummer the furface is generally warmer
j$han at greater depths;.^whereas in winter it is. colder 5
i hence it has been remarked, that th e fea is always colder
in fummei-'-an'd: warmer1 in winter, after a ' ffiormj the
■ water at great’ depths being .-mixed with that at the fur-
face. O t the following’ obfev.yatioris, the three fira
were made by- Lord .M3tn.GRAVE, the three next by
.W s i e s and B a.yu.e y , and the other b y Mr. B ladh.
T h e third column expreffes the .beat o f the air over the
furface o f the fea'v-thrffi.u'rt'h' expreffes the depth o f the
I fea in fe e t; the fifth expreffes the heat of-thi Tea at. tliat
depth, and the Cxth expreffes the heat o f the fea at the
furface. i
F a t ltu d e ., I1 Time. Heat o f A i r . j Depth. l-lcat' o f S e t.' l i t <if Su: face.
-67° Wm N . . June 20 , ‘.■ U%5 - 1 4*780 a^*
7 8 '3° - 4°>S - - ■ - r j
A u guff 3 1 i...
^ 9 - '
1 - 0 r . . Sept. 1 . s ^ i .7 4 .
241- go?/.- 7 2>S ■
, v3 4 - . 44' s. f : o i h XI 60,5 it*, -C o a f '--- W S S Ê ÊM M
- S 7 , , ' Jan. . &
B H
H E ■ -6 t - 4o .--.J ■ f t ? ;
'4 3 ,5
A 5- 40’ ,u t . 20 ' A I 'i j T ijg
, ^ 2.
, .39 a E ‘ 28' I j,. S B t w l n o - -
•’ s s I B Feb.' 2's 1 -K lS i i t 5« -r / S r 1
j j) 2 . A N. 2§ ■ • • ®3 -
^ I J ° 1
j S i -l*s4 1
34;. A s the water in the high northern and fouth-
E*rn latitudes, is, By coid, rendered heavier, than that in
lower warm latitudes, hence arifes a perpetual current
from the poles to the equator, which fotnetimes carries
down large maffes of ice, which cool the air to a ‘great
extent. Inland feas of great extent have been frozen
in very fevere winters. In 1668, the Baltic was fo
djrnily frozen, that C harles-X I . o f Sweden, carried his-
. whole army over i t ; and-the Adriatic was. frozen- in
,1709. T h e temperatures o f land and water differ more
in winter than in fummer; for .in winter, inland countrie
s , from lat._49° to 70" arc frequently cooled down
to 40°, 50°, and fome to>70° below the freezing.point;
■ whereas, the fea below lat; 76° is not colder than 4°
.below that point, in, the northern hemifphere, except’
.fome narrow feas.in the north. Pacific Ocean; but in
■ fummer, 1 confiderable. extent o f land is heated to
more than i-yj/qi 20“ above the. temperature o f the Tea,
.fion y and. fandy.defarts.excepted.
346. T h e temperatures o f the fmaller feas, in gene-
ral, i f not furrounded .with high mountains, are a few
.degrees warmer in fummer, and colder in winter,ithan.
thejftandard ocean ; in high latitudes they are frequent-
Ayrfrozen. . - I
347. T he white tea is frozen in the- winter. ; ,
' ’248. T he Gulph o f Bothnia .1« in a g rea t m&fure
frozen in wifiteil but ynjfunlmef it ljlfiii^ ^m^ ^ fa ted
to 70°. Its general temperature in July is from.48° t j
56 . ’ - . “ A * 1*' - *
34.9. T h e German fea is about 3° colder in winter and
5 0 warmer in fummer, than the AtlanticZ -
350. T he Mediterranean fea is.rfor thegreatqr part of
its :extent, warmer .both-fummer and-winter, than the
.Atlantic, whieE,’ for that reafoh, flows into it; I t s
fometimes frozen in the neighbourhood o f Venice.
,f g £ i. The? Black fr .Mediterranean,
and flows into it. , . , ■ r .
3 j i . T h e iGafpiatt.fea. is. fituated .in .1 the vicinity of
high mountains, and is in a great nieafare frozen in winter.
Its level is faid, by Pallas, to be lower than the
ocean* ■ •sd bQSEhh SgHMflUja
353* S ° me idea may be formed! what altitudes on the
furface o f the globe are acceffible ’ to man, by confider-
in gtlie height .above the fea;- o f the inferiorline .of perpetual
£now. In the middle o f the torrid.,zone, it appears,
from Mr. B ougu er ’ s. ohfavatibns, to be elevated
y z o i yards, and 4476 about the^ropics. vln.niid-
die latitudes there .is- .conltant, fnow. a t .the height of
3300 yards. In.. ]at.,.!;8p0. -north, ...Lord -Mulgrave
found the inferior lin.c o f fnow to [be at the. .height of
406,yards : -whence we ma| corcclu4e,.thatvat the poles,
there is .conltant fnow upon the furface of the earth.
a i M ' '
Off the Divi/ióüsxf ihe Surface o f the Earth. -
g T i e ,fuifage ’o f'th e eaitli contains land and
water.' The great cofteStipn o f water is called-the fea.,
or th e ,ocean ; and'this is divided into three principal
part’s ; the "Affaipjc Ocean, which divides Europe and
Africa from r. meric a ; the Pacific--Ocean,1 or great S oulh
t-ea, wh'icli .divides ffia 'from America ; and the Indian Seaf.
H H r a B a nfi-ica and Mah’cca, Sumatra, Java,
New Holland, Sac. . Btlfidcs ihcfe, theie ai e others which
tak e they^amès. '£ro.m( the go|i^h tries again ft which- they\
are fituated ; as the Irjfld Sea, the German $ea. There'
is alfo the Mediterranean Sea, dividing Europe from A f rica
the Black Sea ; the Cufpian Sea1,|which is -not
wiitb£&e;. &C*.
355' A- ba?) 0r s, a Part ^ e Se,a running into
the land, fo as to have a -conlidcrable portion o f it?J"
-rriöie or (lefs accoidin^^fefe circimifl-Efnces, bounded by
fhores j as^he'hay o f Bifcay-, the bay o f BengalHudfon1 s |
bay, Cardigan Bay ; the gulf óf Veiiicêpffg g tdï o f MexU
cö v. « l i j i i t f M fa-pun, &c. &'C‘. \ I f'th e 'extent into the
land^gl k t lm m it is called a creek, a haven* o r a road.
356. ' A Jlrad, orJlraigbty is a narrow part ©f the/^ea
TUtiiiipg between two countries, and connefting t-wo
feas; as the hiaits o f the ftraits oPGibraltar,
the'ïfraits .of Sunda, the ftraits o f Magellan, &c. See.
357. A confiderablembody^ o f inland fre/li;f^k-|er, is.-
, Galled a lake Geneva, lake tönïafpïMm
of Derwent, &c. See. J
358. A c,onfi|erable ftream o f inland water wh ich,
runs into the fea, is called a tiver ; arïd fmaller fti earns
which run into a river, are palled brooks.
3*59. A current i:s water u.pon the fea.
lender the equator there are forfe^^ Very violent onet,
again ft which a {hip cannoh^ake any way.. There i&-
one which carries | a (hip very fwiftly from''" Africa to
America, but it cannot tet-Thn-the;fa|rie way. 1 Governor
P ow n A l o’bjerves, that this current performs ai conti--
nu al circulation, fetting out from the cdaft:,óf Guinea,,
crofting over the Atlantic, fetting into the gulf|df' Mexico
by the fouth, and fweeping round by t-he ^ t^qm vo f
the gulf, it iftue6 on the norilvlld'e) d^fj^oes along^ihe^
ebaft o f North America till it arrives at 'Newfoundland,
where.it is turned back acrofs the Atlantic to the coaft
o f Europe, and,, thence fouthward to the point from
which it fets out. In St. .George’s Channel there is a
current which ufually fets in eastward. Prom the Baltic -
a :Curreht fetsiiahf©« the BritlfJo Channel. I t is generally-.
allowed,1 that there is alvvays a current fetting round the
Capes o f Finiftè:fnë,;a!nd Örtegal into the bay o f Bifcay ;
and*Mr. R ennell has difeovered that this cuirréht is
■ continued^ and p aC ^M ^ S t N. W.- by W . from fhe
coSft o f France-, to the weftward pp'Scilly and,Ireland;
TV crofting the Atlantic^fherefor^fo^ the F n g lifk Channel,
-he advifes the navigator to keep in the parallel of
48°. 45', at the h ig F p ,, ]eft|the ^ Ci^^^^jjild, carry
him upon the rocks o f S'cilly. „ From an--ignd|^ncb- o f
this current, many :fqms have beemloft bn thofe rock^i, .
360". A very great Extent o f land, is called, £ continent, ,
o f which, there are two’; one contains Europe, Afia ami
Africa, and'the'other contains, America ; and thefe are
^called the four quarters bf the world ; the former is alfo
called the eajlern, and the latter the wejlern continent.
361. A fmall extent o f :land fui rounded by the fea,
is called an ifland; as the ill and o f Great Britain, the
111 and o f Jamaica, the iftand o f Java, 8cc & c.
w m M M frbm the'"main land, and be
joined to it by a naiirdw' tra6t of land, the land fo running
out is called a I'eninfula, or almoft an ifland; and
the narrow t r a i l s called .an IJlhmvs.
363. d f the land projed far into the fea without a or
iflhmuF, it is galled a promontory, the end o f which is
On the^ Corupment Parts of the Earth: -
3,64. The tw’o grand diviiions^of the-earth are what'
are ufually called land and water. ■- Tfte^fu'bdivifions
may be a^,fo|lows : earths and Jlones ; faits ; inflammable
fubftances; metalic. fub.fta'nces.
HI i s , Mineraiogifts divide^
i^^i^^M^^f^M^mopsfpo'nderotis^ magntfiah" or muriatic,'
argillaceous, and ftliceous. A l| flfories'.and earths cbrififc;
oTtfed^fobftances, either fi^gly ,:.b.r; or ^ ^ J ic a lly
combined, together feline, mftammafol’e and metalic
fubftances, for they are feldom found' pure. T h e y
are nearly dnfqlu'bie. in water:, and have their fpecifk
gravitieshetwe-en 5, that o f water'being r. I
3 wm Calcareous 'earth, when freed from the carbonic
acid by means of heat, :a‘hd! rendered pure pio'si all other,
fubftances; h©n'^kutes lime. Its fpecific gravity is about!
2,3. It';q®n|ffies with.all acids, and is eaftfy foluble ttt
the hfariiw I p i forms MieJ^ueicent faits.-
There are a great many fpecimens o f this earth ; as<
llmeftone,;l | B l f l dell&ite, ifland' cryftals, almoft all.
kinds o f fpars, whether tranfparent or opaque, and many
kind«s|o| marble ; aflvtiefe coniift o f this earth combined
with, fome acid. __ T o thefe, we may add, Ketton ft one,
Portland fton.e, Purbeck’ ftone. ’ Vegetable and animat
'eaVhhs1a^TOhn^^b^%Id^eo^us^|^eftafeef,'|mi'ely f o ;
and the former for the moft part,' with a mixture fometimes
of, the calces o f iron and- mah^anefe-jMI^ the
greater’part of,the fubftances o f vegetables is water..
According to fome late 'experiments, 33 pounds o f oak
afforded 'only 3 drachms o f aftieAh jHence we fee why
clay is unfavourable• to vegetation, and how calcareous
earth is introduced into the bodies o f animals, i \ '
■ 3.6-7. Ponderous earth, or barytes, has itsTpec'ific gravity
about 4 .'- ItsTpeeimens are the pbhderou's-fpar, of
marmor metallicum", c-om'm'only | known by; the name oif
Ca-wk;. .j(t^ ^ ||:h e s with acids:; ® d owitfe ^ ^ n ftrb us i
and marine i t ’forms fahs'that do not deliqucfcc. This
"eaHlyiGQ|ffb'ined 'with the «rial fluid, has been found at'
Alfton Moor, in Cumberland; arid refembles alum.
1 368. Magneftan earth hasvits fpecific'gravity;;a;i|^
2,33. I t combines with acids ; and the fpecimens are
, fteatites, foap-rock, French chalk, alheftos, and talk-.
Epfom fait is alfb^a ^combination o f this earth with vi-
trJ®Ii'G';acid. | MI - . I .
. .