Thursday, March 27, 2008

from Journal of the Society of Telegraph Engineers, 1880

(page 317)

Report of an Unusual Phenomenon Observed at Sea
Kurrachee, 24th April, 1880

To the Secretary of the Society of Telegraph Engineers, London.

Sir—In August last I forwarded to the Society an account of some remarkable phosphorescence in the Persian Gulf, witnessed by me on the 15th May. My attention has since been called to a letter from Commander Pringle of H.M.S. Vulture, which appeared in "Nature," page 291, July 24th, a copy of which I enclose for your information.

The independent testimony of an observer who witnessed the same phenomenon at the same time, but at a distance of 180 miles to the west of where it was seen by myself and others, on board the Amberwitch on the 15th May, is so important that I think it is well worthy of record in the Journal of the Society.

Henry C. Mance

(From Nature, July 24, 1879)

The following Report to the Admiralty has been communicated to us for publication by Capt. Evans, C.B., F.R.S., the Hydrographer to the Navy:

H.M.S. Vulture, Bahrein, May 17, 1879

Sir—I have the honour to inform you that, at about 9:40 p.m. on May 15th, when in lat. 26° 26' N. and long. 53° 11' E., a clear, unclouded, starlight night, Arcturus being within some 7° of zenith, and Venus about to set; wind north-west, force 3, sea smooth, with slight swell from the same direction; ship on starboard tack, heading west-south-west and going three knots, an unusual phenomenon was seen from the vessel.

I noticed luminous waves or pulsations in the water, moving at great speed and passing under the ship from the south-south-west. On looking towards the east, the appearance was that of a revolving wheel with centre on that bearing, and whose spokes were illuminated, and looking towards the west a similar wheel appeared to be revolving, but in the opposite direction. I then went to the mizen top (fifty feet above the water) with the first lieutenant, and saw that the luminous waves or pulsations were really traveling parallel to each other, and that their apparently rotatory motion, as seen from the deck, was caused by their high speed and the greater angular motion of the nearer than the more remote part of the waves. The light of these waves looked homogeneous, and lighter, but not so sparkling, as phosphorescent appearances at sea usually are, and extended from the surface well under water; they lit up the white bottoms of the quarter-boats in passing. I judged them to be twenty-five feet broad, with dark intervals of about seventy-four to seventy-five per minute, giving a speed roughly of eighty-four English miles an hour.

From this height of fifty feet, looking with or against their direction, I could only distinguish six or seven waves; but, looking along them as they passed under the ship, the luminosity showed much further.

The phenomenon was beautiful and striking, commencing at 6h. 3m. Greenwich mean time, and lasting some thirty-five minutes. The direction from which the luminous waves travelled changed from south-south-west by degrees to south-east and to east. During the last five minutes concentric waves appeared to emanate from a spot about 200 yards east, and these meeting the parallel waves from south-east did not cross, but appeared to obliterate each other at the moving point of contact, and approached the ship, inclosing at an angle of 90°. Soundings were taken in twenty-nine fathoms; Stiffe's Bank, with fifteen to twenty fathoms, being west about one mile. The barometer was already at 29•25 from 8 to 12 p.m.

I observed no kind of change in the wind, the swell, or in any part of the heavens, nor were the compasses disturbed. A bucket of water was drawn, but was unfortunately capsized before daylight. The ship passed through oily-looking fish spawn on the evening of the 15th and the morning of the 16th inst.—I have the honour to be, Sir, your obedient servant,

J. Eliot Pringle, Commander

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