XXIY 
Rovusts. 
SWONA. 
Deprx or 
Water, 
TIDES. 
ee Ti ae ae ee 
does not extend far beyond the cavity: a boat may pafs within twenty yards of 
thefe whirlpaols with fafety. Fifhermen who happen to find themfelves within 
a dangerous diftance, fling in an oar, or any bulky body, which breaks the con- 
tinuity of the furface, and interrupts the vertiginous motion, and forces the water 
to rufh fuddenly in on all fides and fill up the cavity. In ftormy weather, the 
waves themfelves deftroy this phenomenon. A funk rock near the concourfe of 
thefe rapid tides oceafions 2 moft dreadful appearance. The ftream meeting with 
an interruption, falls over with great violence, reaches the bottom, and brings up 
with it fand, fhells, fithes, or whatfoever elfe it meets with; which, with boats, or 
whatfoever it happens to meet, is whirled. from the centre of the eruption towards 
the circumference with amazing velocity, and the troubled furface boils and 
bubbles like a great cauldron, then darts off with.a fucceflion of whirlpools from 
facceffive ebullitions. Thefe are called .Row/fs,and are attended with the utmoft 
danger tofmall boats, which are agitated to fuch a degree, that (even fhould they 
not be overfet) the men are flung out of them, to perifh without any chance of re- 
demption. It'is during the ebb that they are tremendous, and moft fo in that ofa 
fpring-tide with a weft wind, and that in the calmeft weather; for daring flood 
they are pafied with the-greateft fafety. Vefléls in a calm aré never in danger of 
touching on an ifland or vifible rock, when they get into a current, but are always 
carried fafe from all danger. 
Swona, alittle ifland, the moft fouthern of the Orénies, is about fous miles beyond 
Stroma, and is noted for its tremendous flreams, and in particular the whirlpools 
called the Wells of Swona, which in a higher degree exhibit all the appearances of _ 
the former. What contributes to encreafe the rage of the tides, befides their con- 
finement between fo many iflands, is the irregular pofition of the founds, and their 
little depth of water. The fame fhallownefs extends to every fide of the Orkuies ; 
an evidence that they had once been part of the mother ifle, rent from it by fome 
mighty convulfion. The middle of the channel, between Stroma and the main - 
land, has only ten fathom water: the greateft depth around that ifland is only 
eighteen. The founds are from three to forty-ftx fathom deep : the greater depths 
are between South ‘Ronaldjha and South Weles for in general the ether founds 
are only from three to thirteen; and the circumambient depth of the whole group 
very rarely exceeds twenty-five. 
About thefe iflands: commences a decreafe ‘of the tides. They lie in agreat 
ocean, in which the waters have room to expand ; therefore never experience that 
height of flood which is conftant in the contraéted feas. Here ordinary {pring- 
tides do not exceed eight feet ; and very extraordinary fpring-tides fourteen, even 
when acted on by the violence of the winds *. 
* Murdoch Mackenfie. 
The 
