Su b tr ift .
Altitude: nearly •—
Cor. add - - V
A lt ; nearly - • H -
T rue A l t ; in
■ 9SVi9&
5 ,4 ^ 8 = 9 ,4 5 4 x 12
’ . 1.8,=50^32
. 7620048
y f i j ob
i 7 i 4y »i°8
1 1 . OÏQ0244
68580432 -
342.9:^.16'. 1
.41,83406352
9J 2,5b6 : -
994,340 fatHwas
4966,04 feet
3 w ? heights which do not exceed 4000 or 5000 feet,
Sir G . S hdckbukgh gives the following rule :
-Let Auajtbe mean height o f the two ■ : . - ^ 1 ' — '
- barometers in in ch e s j> = the diference'ofi « §
the tw o .in tenths o f an in ch ; b = the
number offeet in the tabic, correfponding
to. the mean h e ig h to f the two themiome
tors S x z i . the height o f the mountain it
- - # 3 2 . - 30»h
. feet-; then is S H K l t ó X
JBR ^ . ’- a -“ V ‘ : 4 I
E x . Suppofe the barometer St the bot-
tom to be 29,72-inches, thermometer 64°;
th é . barometer at the top to be 27,46,
thermometer 5 8 ° ; to find, the altitude-Of
the mountain.
Ther.J Feet j
32= 5 ,85
35 87,49
[4 0 88,54:
45 89,60
50 90,661
\ s s m M
[•6a.: (92,77 j
W 93>8z
I 70 [94,881
7 5 9 5 >9 i.l
-8a"fe6t99;f
Here A =±28,59 inches ;'a=j-2Z,6 ; themean heat of
the two thermometers — 61, the proportional number
correfponding to which found from the table is 92,98
3 0 x2 2 )6 x9 2 ,9 8
S o j --hence. *= : - ----------------^=2205 feit- the
, . , . - 28,59
height required.
294- T he mean height o f the barometer in London,
from obfervatfons made at theJRoyal Society, is 29,88;
inches ; and' the in a 1 ten pe-ratufe, 1 ding to lv*»_'
R EN HEiT’ sdhe-rwdmeteii, is Jsm \ t Thé/mean .height m
the lurface q f the rfisa.is 3 0 f in c h e s * the hêftt-ofithë'
barometer being 55% anö.that o fth e air 62P, aecoirdhig'
tp Sir George S h uck bu rg h . p
•^ a^ -^ ^ rh e ig h ts io fifom e ’ of- the thoffi 'remarkable
mountains in Engliih .feet;
Feet
Snowden- .:- ; LI
Moel Etiio* ^ fj
3 >ÏJ
Sehihalhen,.Weft fumtmt o f
T P A j e t t o n Cajrii *1 "»1 ï J
Skid|ajw * - f o . j
- - ' rJ44
Helvellyn _ . .
* 3* 4®
Mpnte.Rofa, ■ ' . ,
Montblanc •4 . .
Argentiere ■ . ' ■ . ; j
. 12172
' 44.^- Bne t . ’ T ' §
Mole ■
..'4 8 8 3
S o l e " . .
Saleor " - V
Mont Cenis, at'the ’Poft
Monte Velino * ‘ .
vefuvius Jw - ; 4 - . ■
g | 4%
- 32g4
—
- 8.39-7
*> " $'938
I N T R è Ö Ü G T I Ö N T .
A tn a ; 7; ^
Tajérjff} *" 1' - 1Jcï ti-aSaa-i
Mc k - ' , ’9^97
Heciajoiii -Ijcéland ‘ - 1 » fow l?
Table "Hill, weft .Signal > >- v ;■ 3408*
Pico Riiivo ■ - ' m • - - ... ^ 141
Caralfcötljïf f w i - - '
i_.‘i 7 4 '■ ■ - ■ 1 ■ ■ l i * . - . . , iyzr +'
- f g f i - - t r
P i’c-hihcha i 1, - - ■■ - 1 - - m m !
»1 - > >-i - , ' ‘ T . »5831
Chiïóbofaoo'. - - ■ -r - ' 2c^r 5.
i ; he,' h s i °.f S u 0 ,w d fjr ancTMoel"Eilio are^ab^B
Cabiarven ;Oajay. T he hi gilt iti Sqhffialh’en is above
Weem. ;■ Th;e height o f 'Kirk Yetton is above Leith.
Pier head. The'height pi tdid.i m "i , above Derv er tj
Lake, ar d o f Hej llyn hove L f ,'l e I ike '11 e
heights o f Montblanc, Argentiere, Buet, Mole, Dole,
, »«l» ^ . are'afipv.e tb eL a k e o f Geneva.
The.heighis.'dfthe other mountains are above the Sea.
The Lakejipf',Geneva is 122S feet; above the Mediterranean
S e a , aqetits areatefi depth ir 39:3 feet.
t Q t t tp /R am -g a g e^ ,.
^296,:.T h e - - j R f l m ‘l?7 the
quantity gMaih which falls pigon-the earth’.at any place
wher£4lqd,!:ma.y wifti to ervations, Mconfifis
o f acfjinnel' cp rn'rannicating ^yitii a cylindrical tiibejat its
bottom', into whicS the rain is Goqveyed b y the funnel.
The ;defffil,6f th e 'water in the cylinder is meafiired b y ;
a rule fixed-tdta(fldat;'the rule-paffing through the cen-
fcr'pfitfie funnel'l T h e divisions on the -rule ftow the
number o f cubic inches' o f water ' that have'fallen on a
fuifaii/WjiJM to the area o f the top o f thC funnel.' T he
funnel is fo eontrived as to prevent the Water from eva-
porafi'bg.
297. T o nfe the rain gage, fo much water mull fir'll
be piit'int tin ylBde a ra®ra ■-■ he fl >al, to tlilt ‘
on the role &;ncide^\vith-:the h^rturelpD
the funnel,: ''The gage, fhotfld bc firmly fixedimaplacei
where, whatever’winds blow, the fiSjp f the rain may not
be intercepted h y ,aiiy obllacles. '.vBy ' this inftrument,
the mean at the places
below, has been determined.
XE|ofaSlfn - \
Faria ' -
« a a M i f i •*
Zurich^ SwiCférland
Liilei. Flanders ■' i f
lypmr-h'ci j Effex- -
^ ö tfn fc y j’ Lancalhire
.fep ijd iT ' -
'Eefwic'k ■ 1 -
Inches
I M l
19,6
• 43v25 1
: 32>25
'. 'f fm 'r
\*t>* 9
r 4 2>5
■ 64,5 j
68,55.
. Mr. D^r& 's 'ilSb t'd is us, tha tjth e greatefi quantity
o f rain at'XViidnZ in 24 Hours, ill five years, 178^*178^,
(ry'^p, S 9 1 , 1792, was owi&e fz zfc c fl April, 1792,
4,592 inches ; at fomething lefs. In the level
parts o f this kingdom, and in the neighbourhood' o f 5»»,?
•clqiipUie Acah anumiljdi.pih o f ram i$ about 19 or 20'
.ir'cnt'i'-v
^ 298. Ir'appca'a that* the mmtjrifflw falls.it)places near
-aDciflefe and lefs as the placeshefcorf.e more
inland. T h e quantity which falls on the mejlern coajl o f
England is fometimes twice as .much-as falls at London.
I t is’ ^ lf f f i t e u jfh q r the 'dCarer ffi|< OT«yidOT is to th e
(igtound, the more rain 5tveplld£ftf. ; B y experiments mai$^
'thy ‘Dr. H e b er den *[&om July 1766 to July Jo ot, the
following refults were obtained : On the top o f Well-
minfier Ab bey there fell 12,099 inches ; on the top of
a lioufe, iS.V’i 39 inches; at the bottom o f the houfe,
;225.6o:87iheh!es ; thefe' are1 the mean annual, quantities.
Mr. B arrington; placed 'two rain-gages, one upon
Mount -Remimg in Wales., and the other on the plain fee-'
: 1 iDv JjjU to"-Nfnrjiili\:t thete feifa|.the upper
gage 8,265; ;indhesj and at the lower 8','766 ■ inches.
Hence it appears, th a t ' the Iquant ity o f rain dejiends'
upon the nfcarnefs o f the place to the earth, and not a i t
the height o f the place. In comparing therefore the
quantity o f rain at two places b y two rain-gages', they
lltould be-placed hit the fame difiance, from the earth
{. 1 Qri'dhe 'Hygrmieter.
: 299 The Hygrometer is aii. mfciiment to meafure the
ti'OiUuv and <1 ynefi o f th e 'a ir : and,' is.-formed i f fub-
fianaes which wilt expand or contra hi upon any altera 1
tion o f moifture. Wood expands by moifture^aiid cp<fi-
traftslby.;.deyhefs :• on the1 contrary, chord, catgut, i3tc.
contraft b y ' moillure and expand by drynefs ; and various
mechanical contrivances have been invented, to.'ren-
der fenfible the fmalleft variations in the lengths o f thefe
fuUftanccs'. W e will delcnbe 011c o f them, which any
perfdu may very'ealily makefori himfelf.
Lbfc