396 



♦ KNOWLEDGE ♦ 



[Dec. 28, 1883. 



brighter portion appears about E.S.E. in the mornings, and W.X.W. 

 in the evenings, at an elevation between 20' and 30'. In addition 

 to descriptions given in above letters, I understand that at Trinidad 

 (practically the antipodes of Ceylon) the sun's "face" at rising 

 Teas "bluish," and about setting time " distinctly blue." Surely 

 the " sulphurous vapours " from the recent Krakatoa eruption can- 

 not be the cause of these singular appearances, comparing Krakatoa 

 (as it was) and the quantity of vapour, &c., emitted, with the 

 enormous area over which the singularly beautiful appearances have 

 been seen. 



Sun-spots have been at times numerous, and at others very few, 

 during the last two months. Can any spectroscopist enlighten us 

 as to recent state of protuberances, &c. ? Thos. Radmoee. 



SHOWER OF PERCH— SUNSETS. 



[1067J — Being a constant reader of your valuable journal, I 

 enclose the cutting from to-day's Edinburgh Scotsman, of rather a 

 peculiar phenomenon witnessed in Airdrie, viz., a shower of live 

 perch, last Saturday morning, Dec. 15. Now, perch never, or 

 rarely, swim near the surface of the water, and, if drawn up by a 

 whirlwind, it must have been an extra strong current to have drawn 

 them from deep water. 



I have been much interested in the papers on the beautiful sun- 

 sets lately seen all over the country. I was in Edinburgh last 

 evening, and saw a most peculiar sunset. I watched it from 

 4 o'clock until 5 o'clock, and it varied from grey to green, then red 

 to a copper colour, then a fiery or blood-red colour. It was a grand 

 sight. I have seen a great many of those peculiar sunsets. 



Glasgow, Dec. 17. Johx A. Stewaet. 



STRANGE PHENOMENON. 



[1068] — Seeing so many meteorological phenomena in your ex- 

 cellent paper, Kxowledge, I am tempted to ask for an explanation 

 of the following, which I saw when on board the British India 

 Company's steamer Patna while on a voyage up the Persian Gulf. 

 In May, 1880, on a dark, calm night, about 11.30 p.m., there 

 suddenly appeared on each side of the ship an enormous luminous 

 wheel whirling round, the spokes of which seemed to brush the 

 ship along, "rhe spokes would be 200 or 300 yards long, and re- 

 sembled the birch rods of the dames' schools. Each wheel contained 

 about sixteen spokes, and made the revolution in about twelve 

 seconds. One could almost fancy one heard the swish as the 

 spokes whizzed past the ship, and, although the wheels must have 

 been some 500 or 600 yards in diameter, the spokes could be dis- 

 tinctly seen all the way round. The phosphorescent gleam seemed 

 to glide along flat on the surface of the sea, no light being visible in 

 the air above the water. The appearance of the spokes could be 

 almost exactly represented by standing in a boat and flashing a 

 bull's-eye lantern horizontally along the surface of the water round 

 and round. I may mention that the phenomenon was also seen 

 by Captain Avem, commander of the Patna, and Mr. Manning, 

 third oflicer. LfcE Fore Brace. 



P.S. — The " wheels " advanced along with the ship for about 

 twenty minutes. — L. F. B. 



LARGE METEOR. 



[1069] — I had the good fortune to see the large meteor, on Nov. 

 28, and as " Excelsior" would like to have observations from other 

 parts I thought I would send mine. I was observing Saturn with 

 a 2i-in. achromatic when I saw the meteor cross the field of view, 

 and looking up I saw it passing overhead. I was too startled to 

 note the time it occupied, or the very colour ; but I noticed par- 

 ticularly the place of disappearance, which was about half a degree 

 west of Gamma Ursa Minoris. Heniy T. Vivian writes as follows 

 in English Mtc' aaic, Dec. 14. " At 10.35 a brilliant white fire-ball 

 became visible between X i and Eta Draconis at about a third of 

 their distance from the former star, and made a direct course 

 towards the horizon, leaving in its wake a train of small sparks. It 

 vanished about 15° above the horizon." Staegazer. 



Mexboro' Common, near Rotherham. 



LUNAR PHOTOGRAPHY FOE SMALL TELESCOPES. 



[1070] — The following method requires neither clockwork nor 

 camera, and gives fair results, interesting to the worker, if not 

 scientifically valuable. 



Buy a shilling glass-cutter and cut up a Wratten Gelatine 

 " Instantaneous " ^-plate into small squares with the comers 

 rounded off such as will go inside your lowest power eyepiece and 

 rest on the diaphragm ; remove the lenses, screw on a solar dark 



glass, and use the eyepiece as your dark back ; find the visuaVfocus 

 roughly with a piece of ground glass or tissue paper, and find the 

 actinic focus by trial, as described by Mr. Brothers in an early 

 number of Knowledge. The exposure is made as short as possible 

 by holding a piece of millboard close in front of the object-glass, 

 whipping it away and instantly replacing it. A tenth of a second 

 is quite enough if a strong developer be employed. Of course, due 

 photographic precaution is necessary throughout. The moon's 

 motion during the exposure is less than 2", a quantity quite inap- 

 preciable in such a photograph. A silvered glass reflector makes 

 the method even simpler. H. L. C. 



AN ALARMING INCIDENT. 



[1071] — Though in the present day of scientific discovery and 

 iron ships, the electric flash has lost many of its terrors, the incident 

 of a vessel being struck by lightning still remains one of the most 

 startling and alarming events that can be met with at sea. This is 

 especially the case when the weather is clear and moderate, and 

 the blow falls in the darkness of the night or of the early morning 

 in the open seaway, for then, not only is danger least expected, but 

 the anxiety and alarm which such an occurrence would naturally 

 inspire at any time must necessarily be prolonged and exaggerated 

 by the difiiculty of ascertaining whether any damage has been done 

 or not. It was under such circumstances that the fine screw 

 steamer Southijate, of London, was struck last September, whilst on 

 her way, laden with gi'ain, and homeward bound, through the Black 

 Sea from Odessa, and though no permanent harm was inflicted, the 

 feelings of anxious doubt and uncertainty that for a time had place 

 on board can be more easily imagined than described. 



At one o'clock in the morning, those who were below were sud- 

 denly roused from theii- sleep by the sound of a fearful crash upon 

 the steamer's side, which, making her shiver and tremble, rang out 

 on the iron like the blow of a heavy hammer. Then quickly fol- 

 lowed two other blows, or seeming blows, much weaker than the 

 first, as if some object in the way were being grazed upon. It does 

 not need a sailor to understand how fraught with dangerous mean- 

 ing such an event must be to the voyager, whose life depends on 

 the soundness of the thin walls of the modeni merchant steamer, 

 and sudden as was the waking, and quickly as the blows succeeded 

 one another, the last report had hardly died away when the captain 

 was on deck, looking round in every direction, but in vain, for 

 something to account for the alarming sounds. Strangely as it 

 then appeared, though they had seemed to come from the starboai'd 

 quarter (vide note), just in front of him, there was not a sign of 

 anything unusual to be seen or heard. The heavy rain pattering on 

 the planks, the spla-'h of the waves against the sides, and the 

 regular rattling of the screw alone broke the stillness of the night ; 

 and a glance over the bulwarks showed no issuing grain from rent 

 plates, no wreckage telling of a vessel run down, no surf marking 

 the place of an unknown rock. 



The true cause, however, did not long remain a mystery, for 

 when he reached the Ijridge, feeling the deck warm to his bare feet 

 as he went, he found the chief ofiicer just recovered from the 

 stunning effects of an electric flame that had fallen on the steamer 

 in a sudden stream, as the lightning, which all the evening had 

 been continually playing in the heavens in bright floods of thunder- 

 less light, passed over her in its course across the sky from west to 

 east. To the startled watchers, it had seemed as though the masts 

 were rattling down around them as the glowing fire poured along 

 the bridge, and over the deck beneath, until it burst on the star- 

 board side with a loud report, which, followed quickly by two 

 sharp thunder-claps, accounted for the sounds that had been heard 

 below. It was but for a moment that the steamer was enveloped 

 in light, and then all was dark and quiet again, though there was 

 little rest for any one on board until a careful search disclosed the 

 comforting fact that not even a mark remained to show the course 

 of the dangerous stream. 



From the various accounts of the event the writer heard the 

 following day, he was surprised to gather that the flash, instead of 

 striking the "iron masts in the first place and passing along the iron 

 stays to the sides, as might have been expected, appears to have 

 fallen on the water or the stem, and then to have risen over the 

 steamer, for the men who were on the forecastle at the time 

 described the flame as coming up from the sea, whilst some who 

 were hoisting a staysail farther aft, felt it as a hot breath moving 

 in the direction of the stern. It may also be worthy of note that 

 all, whether in the forecastle or in the after cabins, heard the 

 sounds as if the blow had been struck in their immediate neigh- 

 bourhood, though always on the starboard side. 



The incident occurred about latitude 42° 26' N., and longitude 

 29° 13' E. J- TVBRELL Baylee. 



Note. — The starboard quarter is the right hand side, looking from 

 stem to stem, at the stem of a vessel. 



