3^0 PRINCIPAL RIVERS. , . 
winding course becomes a delightful on’^ment. 
the most beautiful landscape still more exquU , ^ 
ing. At its fountain head it is nothing mom o[/ 
imr. At Its louniain neau u is iiul^..5 ^ , 
v«n of water, oozing from a hill Lte 
on which account it has been supposed °'^^^aiid 
brought from the sea by subterraneous ducts, 
y 9 . V. _ 1 ir» ♦V.on* nnssaS' 
>v 
lost their saltness by percolation in their ° 
eartli. If this be conceded, it is not so 
eartli. If this be conceuea, ii is not su 
what power the water rises above the level jlJ J 
wnai powei uic ,„,,erali) , ''i 
summits of mountains, where spring g 
it being contrary to the laws of l^i-dros at c VJ 
^ould rise in a tube abpve the level of otbef,4 
Halley has on this subject ' lute* 
has been most generally received. He attrio > t 
has been most generally iceuiv-^u. .... “- of ui'=.a,'l 
of springs ^to vapoun raised b^ the action 
of springs to vapouis laiacu gj, !•>; .Fj 
well as by the agitation of the winds, ® gur 
He made severd experiments to show tl'^t ‘P 
dent fund to supply all our springs, rivers, jc- / 
watpr whlrh the McdlteiTcin^^* tnfO’iiiK 
wXr"as'’the'Tharaes, including in this esn»*‘^iciS' 
which flows into that sea from the small 
wnicn nows iiiiu u, a.. te y 
the Thames is found by calculabon 
and three millions of tons of water daily. 
, will, therefore, evacuate^ eSC^tS 
don’®tlfj 
It. / 
rivers. 
cuate little moio 
millions of tons in a day ; and this scarcdy e 
of what he hatl, by preceding experiment ^^^j 
to be raised in that time in ’■*'® fot ^ j 
thus discovered a source abundantly sumcic A 
of fountains. • ■ i„e 
To explain this theory on the principles 
the Doctor considers that if an atom of s* 
me uuuiui tUncs , «v-|f 
expanded into a bubble, so as to be ten , ,, 0 ^ J 
diameter as when it was in its j^iy l'l5 I'Y 
water, that atom would become specitictav ^\,e 
and would, therefore, rise so long iJ’Jj.y 
■ surface . 1,1 , 
dcSf,y«'/j 
tlifi .hc y 
the air, — . . • 
which first separated it from the 
should continue to distend it in the same 
ILUlAiV/ ww -- 
sequently, that vapours may be raised tro ^ |ij 
manner, till they arrive at a certain 9 
phere, in which they find air of equal sp 
