( 447 } 
liis Vbmdm ttthmtni) and improved and firft brought into ufe 
here, diners years ago , by the Noble R t Boyle, who alfo, as him- 
felf inforteed the Publifber , hath in fome of his Writings , yet 
unpublifht, fee down a full Defcription thereof. 
It is fuch a Glafs-Tube as is reprefented by Fig, y o blown at a 
Lamp, and poifed in good common Water by putting Quick- fib 
«ver into it, until it fink fo low, that nothing appear above the Su- 
perficies of the Water , but the Top which done it is to be feal- 
ed up , and to be graduated on its fide, into whatparts you pleafe § 
which may be done with a Diamond. And then , being put into 
any Water to be weighed , it will , by its more or lefs finking into 
it, fbew the differences of the Waters gravity. 
T O perform this , let there be made a Square Woodden Bucket 
(fuch as C in Fig . 8. ) whofe bottoms E E are to be fo con- 
trived, that the weight A do fink the Iron B (to which the Bucket 
C is faftned by two Handles D z> , on the ends of which are the 
moveable bottoms or Valves EE) and thereby draws down the 
Bucket ♦, the refiftance of the Water keeps up the Bucket in the 
pollute c , whereby the Water hath a clear thorow-pafiage all the 
while it is defending whereas, asfoon as the Bucket is pulled up- 
wards by the Line J 1 , the refiftance of the Water to that motion, 
beats the Bucket downward , and keeps it in the pofture t? • where- 
by the included Water is preferved from going out , and the Am- 
bient Water kept from getting in. 
By the advantage of 1 which Veflel, or fuch like, you may come 
to know the Degrees of Subnets oi Sea- Water , according to its 
mearnefs to the Top or Bottom 5 or rather, the Conftitution of the 
Sea- Water in feveral Depths of feveral climate v Likewife, whe- 
ther in fome places of the Sea , there be any Sweet Water at 
the Bottom 5 the Affrmative whereof is to be tee t with in the 
Eafl-Indian-Foyagee of Van Lwfckten , , who fag. . 1 6, of that 
Work , as’tis Englijhed, records, that in the PerfianGulpk, about 
‘the Hie of Baharcm , they, fetch up with certain Vefttlsf which he 
rom any 
de- 
