coaft of Sfain^ which gives denomination to the Strdgk^ 
and Ctuta on the Barbarj coaft : at which places Hercuks is fiip« 
pofed to have fet up his Pillars. What becomes of this 
great quantity of water poured in this way, and of that, 
which runs from the Eux'me into the Bojporus and Prcpont^s^ and 
is carried at laft through the HtUeffont into the ^.^^an or Ar-^ 
ch^elago. is a curious fptculanon^ and has exercifed the wit and 
underftanding of Philofofhers and Navigators. For there is 
no fenfible rifing of the v^ater all along the Barhary Coaft^ e- 
ven down to Akt^candria^ the land beyond Tripli^ and that of 
^gypt , iyitig very low , and ealily overflowable. They 
obferve indeed, that the water rifes 3 feet, or 3 feet and an 
half, in the gulfh of Ftnm, and as much, or very near as 
much, all along the Riwrao^ Gemua^ as far as the river 
jirno : but this rather adds to the wonder. 
^ I here omit to fpeak at large of the feveral hyfothefes^ 
which have been invented to folve this difficulty : fuch as 
jubterrantopps hejus, cavitys and indraUghtS, exhalations by the 
Sujt beams, the ^running out of the water on the African fidt, as if 
there were a k^nd of circular motion of the water,and that it 
only flowed ii\ upoa the Chnftian fhore : which latter I look 
upon as a meer fanfy, and contrary to all obfervation. 
My conjeilure is, thsit there is an under-current^ whereby as 
great a quantity of water is carried out, as comes flowing 
in. To confirm which, belides what I have faid above a- 
bout the difference of tides in the ojjing, and at the Shor. in the 
Downs, which neceflfarily fuppofes an under Current, I fhall pre- 
fent you with an inftance of the hke nature in the Baltuk, 
Sound, as I received it from an able feaman, who was at the 
making of the try al. 
He told me, that being there in one of the Kings Fregats, 
they went with their Pmnace into the middk fream, and were 
carried violently by the Current : that foon after they fank a 
huchet with a large Cannon bullet to a certain deith of water, 
which gave check to the boats motion, and finking it ftill 
lower and lower, the boat was driven a head to wind- ward a- 
gainft the upper Current : the cirrrent aloft, as he added, not 
being above 4 or ^fdtbom deep, and that the lower the buc- 
ket was let fall, they found the mder-Curnm the ftronger, I 
defigned 
