(447) 
his Fundus SHhtemm\ and improved and firll brought into ufe 
here, divers years ago , by the Noble R. Boyle y who alfo , as him- 
felf informed the Publifber , hath in fome of his Writings ^ yet 
unpubliflit, fct down a full Defcription thereof. 
Itis fuchaGlafs-Tube as is reprefented byj'/g-, 7. blown at a 
Lamp, andpoifed in good common Water by putting ^/V/ir-y?/- 
wrintoit^ until it fink fo low, that nothing appear above the Su- 
perficies of the Water , but the Top 5 which done it is to be feal- 
edup, and to be graduated on its fide, mto what parts you pleafe^ 
which may bedone with a Diamond, And then , being put into 
any Water to be weighed, it will, by itsmore or lefs finking into 
it 5 fliew the differences of the Waters gravity. 
1^0 fetch Water from anjT>epth of the 
Sea. 
To perform this, let there be made a SquareWoodden Bucket 
(fuch as C in Fig. 8. ) whofe bottoms E E are to be fo con- 
trived, that the weight do fink thelron^ (to which tht Bucket 
C is faftned by two Handles D D, on the ends of which are the 
moveable bottoms or Valves EE^ and thereby draws down the 
Bucket -J the refiftance of the Water keeps up the Bucket in the 
pofture C , whereby the Water hath a clear thorow-palTage all the 
while it is defcending : whereas, as foon as the Bucket is pulled up- 
wards by the Line J', the refiftance of the Water to that motion^ 
beats the Bucket downward , and keeps it in the pofture G where- 
by the included Water is prefervedfrom going out , and the Am- 
bient Water kept from getting in. 
By the advantage of which Veffel, orfachlike, you may come 
to know the Degrees of Saltnefs of Sea- Water , according to its 
nearnefs to the Top or Bottom 5 or rather, the Conftitution ©f the 
Sea- Water in feveral Depths of feveral Climats: Likewife, whe- 
ther in fome places of the Sea , there be any Sweet Water at 
the Bottom 5 the Affrmative whereof is to be met with in the 
Eafl' Indian-Voyages of Fan Linfchoten , who fag. 16. of that 
Work, zs'ns Engli(l)ed ^ r^covds^thumiht PerpanGulph ^ about 
the Ifle of Baharcm , they fecch up with cei tain Vefltrls ( wliichhe 
