The Prerace. 
and by : a finall Syphon Idraw out the Aferéury fo long,till find the furface of 
it AB inthe head totouch exaGly the line X Y; at which time I immedi- 
ately take away the Syphon, and if by chance it be run fomewhat ‘below 
the line XY, by pouring in gently a little Aéercury atF, Iraife itagain to 
i defired height , by this contrivance I make all the fenlible rifing and’ ial 
of the Mercury tobe vifible inthe furface of the Mercury in the Pipe F 
ne fearce any in the head AB. But becaufe there ‘really is forie finall 
chans of the upperfurface alfo, :I find by feveral' Obfervationshow, muck 
it rifes in the Ball, and fallsin the Pipe F, tomakethe diftance between the 
awo furfaces an inch greater then it'was before’; and the meafure thatit 
falls in the Pipe isthe length of the inch-by which am.to mark the parts of 
the Tube F; orthe Board on whichit lyes, intoinches.and Decimals: Ha- 
ving thus juttned and divided: it, I have a large Wheel M'N'O P, whofe 
outmott limb is divided into two hundred equal parts} this by cettainfmall 
Pillars is fixt on the Frame RT, in the manner expreft inthe Figure. In 
the middle of this, on the back fi de, in aconyenient frame, is placed a {mall 
Cylinder, whofe circumference is equal to twice the length of one of thofe 
divifions, which] find anfwertoan inch of alcent, or decent, of Afercury : 
This Cylinder I,is movable ona very:fmall Needle, on the end of which is 
fixt avery light Index K L, all which are fo pois ‘don the Axis, or Needle, 
that no part is heavier then ‘another = ‘Then about ‘this Cylinder i is wound a 
{mall Clew of Silk, with two fmall {teel Bullets at each end of it, G H3: one 
of thele, which isfomewhat the heavier, ought to be fo big, as freely ae 
move to atid fro in the PipeF 5 by means of which contrivance ; every the 
lea(t variation of the height of the Mercury will, be'made excecdinauibie 
by the motion to and fro of the {mall Index K Lee 
5 ae We + ver 
But this is but one way of difcovering the Auris of the Earth mixt 
pith the Air 5 there may be perhaps many others,witnel3 the Hygrofcope, 
an Infirument whereby the watery fleams volatile im the’ Air are difcerned, 
which the Nofe it felf is riot able to find. This 1 have defcrib'd in the 
following Tra&t in the Defcription of the Beard of a wild Oats. Otbers there 
aresnay be difcovered both by the Nole, and by other wayes allo. Thus 
thefmoak of burning Wood is {melt, feen, and fufficiently felt by the 
eyes: The Mtg: of burning Brimftone are {melt ard difcovered alfo 
5 the deftroying the Colours of Bodies , asby thé whitening of a red 
Rofe : And who keiows, but that the Indufiry of man, following this me- 
- -thod.gnay find out wayes of improving this fenfe to as great a cette OF ag 
fettion as it isin apy Animal, and perhaps yet higher. ys 
“Tis not improbable alfo,put that our tatte may be very valle d, 
either by preparing our taft for the Body, as, after eating bitter things, 
wate other Vinous Raneise are more feah bly tafled’; or elfeby pre- 
paring | 
