OcToBER 5, 1899 | 
lower current less than 1°84 and more than 3°22 feet per second. 
Mean velocity of the under current was 2°32. 
The upper current does not everywhere occupy the full 
breadth of the strait. It flows in some places under the north 
coast of the strait, and in other places under the south coast. 
Lower current also does not flow over the whole breadth, and 
occupies a certain part of the bed of the strait. In my book I 
give a chart of the Bosporus, where I show direction of the 
upper and lowercurrents. A glance at that chart will show that 
there are places where both currents can be found, and there are 
places where the instrument will show the existence of only one 
of ‘them, and in some places the explorer will not find either 
upper direct current or under current. 
Difference of level of Black and Marmora Seas, calculated 
from difference of specific gravity of water, is 1 foot 5 inches. 
1775 
Mean specific gravity of water (sizs) entering from the Black 
Sea into the Bosporus is 1‘orgo. Mean specific gravity of water 
entering from the Marmora into the Bosporus is 1'0283. 
By upper current pass 370,000 cubic feet per second. By 
lower current pass 200,000 feet persecond. Difference between 
these two figures being 170,000 feet per second is due to the 
excess of fresh water in the Black Sea. 
I hope that after reading these figures and deductions Admiral 
Wharton will change his opinion, and come to the conclusion 
that my idea about double current in the Bosporus is based, 
not only on theoretical considerations, but also upon direct 
measurement. 
Admira Wharton expresses also his opinion about double 
current of the strait of Bab-el-mandeb, and says that “‘ there are 
none of the differences of specific gravity.” Imay be permitted 
to refer to my other book, ‘‘ Le Vitiaz et l’Ocean Pacifique,” 
where I give (p. 136, plate xxvii.) specific gravity of the strait 
of Bab-el-Mandeb measured by myself. Examination of figures 
given there by me shows that there is a difference of specific 
gravity which produces double current in that strait. 
Nobody can deny that the wind has a great influence upon 
the movement of surface water; but I hope that Admiral 
Wharton will agree with me that differences of specific gravity 
has also some influence upon the circulation of water in the seas 
generally and in the straits particularly. S. MAKAROFF. 
Lrmack, Newcastle-upon-Tyne, September 23. 
Movement of Sea-Gulls with a Coming Change of 
Weather. 
THE suggestion that sea-gulls may have some meteorological 
sense would be best tested by inquiry as to whether there was, 
at the time of their westward flights, observed by your recent 
correspondents, any other possible motive for their journeys ; 
and particularly what food was available in the Channel at the 
time. 
Neither of your correspondents needs to be told that every 
sea-gull is a semaphore to every other sea-gull in sight of him, 
nor that one gull ** working on”’ fish will presently be surrounded 
by others from all sides. 
In clear, fine weather the news of abundant sprats would be 
passed. along the Channel in this way, faster than by military 
signallers, and answered by a concentration of gulls much 
speedier than any possible to troops. 
Moreover these birds, and vultures, as I know from repeated 
observation, do not merely fo//ow each other round the head- 
lands. If a gullina bay sees another gull hurrying from the 
offing into the next bay, he does not fly round the headland 
between, but rises over it, well knowing that from the upper air 
he will see whatever hurried the outer gull. As he does so his 
motions will be observed, and probably acted on by others 
further within the first bay ; and if food be failing in the Thames, 
and abundant off the Wight, there will be plenty of gulls flying 
across Kent, and some across even Surrey. Here in Chelsea I 
seldom see large gulls on the river. But it is a common 
enough thing to see them flying high overhead to the south- 
westward. 
Westerly and south-westerly gales are so common in the 
Channel that neither beast nor bird can make any movement 
without a good off-chance of finding one on his way. It has to 
be remembered that most of our migratory sea fish are apt to run 
up Channel in the warm half of the year, so that the message, 
“* Plenty of fish on the surface,” is probably most often passed 
from west to east. 
NO. 1562, VOL. 60] 
ING AMI OD I'S 
945 
We shall, I think, need a good many simultaneous observ- 
ations at various points and of various matters before we make 
it even probable that sea-gulls can foretell a south-west wind, 
and will then go to meet it. They cannot eat it ; and, if strong, 
it will give them little leave to eat anything else ; so the motive 
is not apparent. W. F. SINCLAIR. 
102 Cheyne Walk, Chelsea, S. W., September 22. 
On the Use of the Fahrenheit Scale for Observations 
on Sea Temperatures. 
In addition to the Fahrenheit scale being so much more 
practical for observation in meteorology than the Celsius, allow 
me to point out that in observations for ocean temperature it is 
even more so, and especially when we come to deal with ob- 
servations taken in the polar regions. Here with the Fahrenheit 
scale we have never to deal with a minus reading at all; whereas 
with the Celsius scale it is a constant change from plus to minus 
and minus to plus. This introduces a source of very serious 
error both in observation and calculation, besides adding to the 
work, and therefore the cost of working up results. The boon 
of never having to think of a minus in such work is not to be 
lost sight of for the sake of fashion. As one who has taken 
part in extensive observation and calculation work at Ben 
Nevis Observatory, on board ship, and in connection with the 
Scottish Fishery Board, I would also urge the use of the 
Fahrenheit scale for meteorological observations on the same 
grounds as Mr. J. Y. Buchanan and Mr. H. Helm Clayton. 
Joppa, Edinburgh, September 25. | WILLIAM S. BRUCE. 
Cave Shelters and the Aborigines of Tasmania. 
I HAVE just received news from Mr. J. B. Walker, ot 
Hobart, of the discovery of some interesting relics of the 
aborigines of Tasmania. Mr. Walker accompanied Mr, R. 
M. Johnston, the Government Geologist, on an expedition in 
search of some remains of Tasmanians, and the party were 
rewarded by finding a hitherto unknown so-called quarry 
where the natives manufactured some stone implements, also 
a cave which showed considerable evidence of having been 
used by the aborigines, as well as a tree notched by them 
for climbing purposes. The sandstone cave or rock shelter i 
situated in Hutton Park, near Lovely Banks. The quarry is 
situated at Coal Hill, two miles north of Melton Mowbray, 
about 40 miles N.N.W. of Hobart, and 1100 feet above the 
sea-level. 
The discovery of this quarry makes the tenth known quarry 
used by the aborigines, and the first mention of their use of 
cave or rock shelters. H. Line Roru. 
Halifax (Yorks.), September 27. 
The Darjeeling Disaster. 
UNUSUALLY large seismograms were obtained in the Isle 
of Wight on September 3, 10, 17, 20 and 23. The first 
three: refer to disturbances originating in Alaska. The fourth 
refers to disasters in Asia Minor, and the last to an earthquake 
having an origin as distant as Japan. Since the 23rd in the 
Isle of Wight, and I believe also at Kew, not the slightest 
movement has been recorded. The inference is that the great 
earthquakes reported as having taken place at Darjeeling on 
the night of September 25-26 are at the most small and local, 
and are not likely to have been recorded outside the Indian 
Peninsula. It is extremely likely that the tremors noticed in 
Darjeeling were due to iandslides, and seismic phenomena were 
entirely absent. J. MILNE. 
Shide Hill House, Shide, Newport, Isle of Wight, 
September 27. 
Lectures at the Royal Victoria Hall. 
I SEE in your issue of September 21 (p. 513) the statement 
that I am to lecture at the Royal Victoria Hall on ‘ Photo- 
graphs taken in the dark.” I beg to say that the title I gave 
for my lecture was ‘‘ Pictures taken on a photographic plate in 
the dark.” I suppose the authorities at the Hall consider the 
titles identical. I do not. W. J. RUSSELL. 
St. Ives, Ringwood, Hants, September 26. 
