( 195 ) 
fily pra(fticable, and all the Accidents of it exadly as 
they fet forth, yet nothing like what they infer can pofr- 
libly be concluded from it 5 onlefs Water ^ which they 
fo plentifully beftow upon the Plant in thh Experiment^ 
be pure homogeneous, and not charged with any terre- 
firial Mixture 5 for if it be, the Plant after all may owe 
its growth and encreafe in ti rely to that. 
Some Waters are indeed fo very clear and tranfparent^ 
that one would not eafily fufpefl; any terrejlrial Matter 
were latent in' them : bet they may be highly faturated 
v/^ith fuch Matter^ tho* the Eye be not prefently able 
to defcry or difcern it, 'Tis tree, Earth is an opake Bo- 
dyi but it may be fo far diffolved, reduced to fo ex- 
treme fmall Particles, and thefe fo diffufed through the 
njoatery Mafs^ as not fenfibly to impede 'vifion, or render 
the Water much the lefs diaphanous. Silver is an Opake^ 
and indeed a very denfe Body 3 and yet, if perfedly dij- 
folved in Sp. of Nitre ^ or Aqua Fortis^ 
that is reBiJied and thorowly fine^ it does * Pro'vided th silver be 
not darken the Menftruum, or render it lefs ab/oiutely refinM : 
% r a i 1 Tn ^^^fi o.dtntxture of Cop- 
pellucid than before And other initan- per c^^vV/ produce a blue Tin- 
ces there are, that oftentimes great quanti- «^t^re in the Menftruum ; as 
ties of Opake Matter are fuftain'd in Fluids, 'l^lfJl""' ^'^^'^^ 
without coniiderably jftriking the Eye, or 
being perceived by it. So that were there Water any 
where found fo pure, that the qoickefi Eye could dif- 
cover in it no terrejlrial intermixture ; that would be 
far fhort of a Proof, that in reality there was 
none, ' 
But after all, even the clear ejl Water is very far from 
being pure and wholly defecate, in any part of the World, 
that I can learn. For Ours here, I have had an Oppor- 
tunity of Examining it over a good part of England % 
and cannot fay I ever met with any, that, howevQv frejh 
and newly taken out of the Spring, did not exhibit, even 
F f 2 to 
