NATURE 



\Fcb. lo, 1 88 1 



D.;cembe: 



Ice tluLknoss 

 .« 4 feet 7 inches . 



Monthly 

 Mean Temp. F. 

 — 24° "5 below zero 



January 24 ... 5 feet 9 inches . 



February 25 ... 7 feet o\ inch . 



April 25 * ... 8 feet il inch 



May 25 ... 8 feet t\ inch 



4 in 35 days ... -3o'-6 „ 



6 in 32 days ... — 34''9 ,, 



25 in 59 days ... - 8°-5 „ 



one 30 days ... +24 above zero 



The abovj table shows that the ice ceased to increase in thick- 

 ness some time between April 25 and May 25, after which it 

 decreased rapidly ; but I was uiiable to decide what proportion 

 of thii decrease was due to thaw and evaporation from tlie 

 surface, and what amount from the lovier part of the floe that 

 was under water : no doubt by far the greater effect was produced 

 by the two first causes. 



Eight feet may perhaps be considered a fair or rather a high 

 average of one winter's formation of new ice (not increase of 

 an old floe) over the whole of the Arctic Sea, because Repulse 

 Bay, although in a comparatively lo.v latitude, was particularly 

 favourable for ice-formation, there being no currents of any 

 con-equence. Where there arecarrents, one year's ice does not 

 exceed three or four feet. 



The winter's ice of 1S75-6 at Discovery Bay, in latitude 

 81° 40' N., did not exceed, if I remember correctly, six feet in 

 thickness. 



Even were these great compound floes, callel Palfeocrystic 

 ice, found at or near the Pole, and of only the same thickness 

 as those seen at Grinnel Land — instead of "hundreds of feet" 

 — they would not probably have nearly so low an average tem- 

 perature all the year round as 20° F. below the freezing-point of 

 water, because only one-sixth of their mass would be exposed to 

 very low temperatures for about six months of the year, the 

 surface being during that time protected by a more or less thick 

 covering of snow, whilst at least five-sixths of their bulk was 

 under water, having a temperature for the w hole twelve months 

 at or above the freezing-point of the sea. The que.stion is, 

 how far the very low temperatures of an Arctic winter do pene- 

 trate a mass of, say sixty feet of ice, the surface of which is 

 covered with a foot of snow, and fifty feet or five-sixths under 

 water of a temperature at or above the freezing-point of the 

 sea ? 



From my experience on a much smaller scale, I do not believe 

 that the atmospheric cold would, under the circumstances men- 

 tioned, penetrate to the lower surface of ice sixty feet thick ; 

 and if it does not do so there would be no increase to its thick- 

 ness during winter.^ 



An excellent example of formation of Paljeocrystic ice, or 

 floe-berg is afforded by the experience of the Austro-Hungarian 

 Expedition under Weyprecht and Payer in the Barentz Sea in 

 1873-4. Their ship was lifted high out of the water by the 

 pressure of the floes, which were forced over an 1 under each 

 other to a great thickness and extent in a very few day-. 



The ship and her crew were helplesdy drifted about for many 

 months, during which the flies were frozen together into one 

 solid mass, and the inequalities of the surface in a great measure 

 filled up with snow-drift. John Rae 



4, Addison Garden^, January 29 



On the Spectrum of Carbon 



In addressing to you my former letter regarding Dr. Watts's 

 experiments on the spectrum of carbon, it was not my intention 

 to enter on any discussion concerning matters of opinion. The 

 reference made in that letter to the difficulty of perfectly drying 

 a gas so as to eliminate the ultra-violet sj^ectrum of water had 

 reference to gases at ordinary atmospheric pressure ; and the 

 expectation a gas will be dried '• to all intents and purposes " 

 by the use of a U tube of phosphoric anhydride goes far to 

 explain the origin of different experimental results. The cogent 

 experimental evidence which Dr. Watts justly demands may, so 

 far a- the relations of carbon and nitrogen are concerned, be 

 found in our complete papers on the spectrum of carbjn com- 

 pounds in the Proceedings of the Royal Society. 



The supposition, which appears to be a difticulty to Dr. Watts's 

 mind, that traces of nitrogen in hydrocarbons give with the 

 spark the spectrum of nitrocarbous, and that traces of hydrogen 

 in cyanogen give the hydrocarbon spectrum, is not only " reason- 



» The mean temperature opposite to April is that of March and Apr.l 

 combined, and it will be seen that the average increase of ice f jr each of 

 these months is only 6! inches. 



* That the sea rai>es the temperature of the ice on its surface even in very 

 cold weather, is evinced by the fact that a snow hut built on the ice is 

 r than if built on the land. 



able," but appears to me most consistent with the spectrum 

 observations on the whole, and with the chemical regarding the 

 formation and relations of acetylene and hydrocyanic acid. 

 Cambridge, January 22 G. D. LiVEING 



Vibration of Telegraph Wires During Frost 



Mr. T. M. Reade asks for an explanation of this pheno- 

 menon. In Science Gossip for 1874, 1:1. 254, there is a short 

 article of mine on " Frost Phenomena," and one of those referred 

 to is this curious vibration of telegraph w ires. 



The ex|)lanation there suggested, which was only a guess, is 

 probably incorrect ; but I think I can give the true one now, and 

 it is, as usual in such cases, extremely simple. 



Ploar frost is only deposited in air which is nearly at rest ; a 

 strong wind shakes it down as it forms. But there is nearly 

 always a slight air-current in one definite direction, and the ice 

 spicules are built up "in the teeth " of this current, that is on 

 the windward side of the wire or twig. 



They always point to-cvards the wind. When they have 

 attained a length of, say, half an inch, if the direction of the air- 

 current slightly changes, it may strike the comb-like fringe no 

 longer on the points, but on the side, and, obtaining thus a 

 leverage u^on the wire, will twist it round till the pressure is 

 balanced by the torsion. If the pressure were absolutely constant 

 the wire would perhaps remain in this position, but the very 

 slightest variation of pressure would set up a vibratory motion, 

 and this, I think, must be the true cause of the phenomenon. 



Birstal Hill, Leicester, February 5 F. T. MoTT 



The Star Oeltzen, 17681 



The star Oeltzen, 176S1, whose spectrum w-as announced by 

 me to consist mainly of a yellow and blue band (Nature, vol. 

 xxii. p. 483), proves to belong to the same class as the three 

 stars in Cygnus discovered by Wolf and Kayet in l^d"] {Comptes 

 rendus, vol. Ixv. p. 292). A curious feature of these spectra is 

 that they resemble each other without being identical, the 

 relative brightness of the lines being very different. A further 

 study of them is much to be desired. 



Cambridge, U.S , January 24 Edward C. Pickering 



Zeuglodontia 



In consequence of my letter in Nature, vol. xxiii. p. £4, the 

 sub-editor of the Graphic was kind enough to send me the 

 number of that paper containing the engraving of the animal 

 seen from the City of Baltimore (not City of Washington, as I 

 had misunderstood), and which is that of April 19, 1879. The 

 sketch from which this was taken was ;ent by Major H. W. J. 

 Senior of the Bengal Staff Corps, w ith the following description, 

 viz. : — 



"On January 28, 1879, at about 10 a.m., I was on the poop 

 deck of the steamship City of Baltimore, in lat. 12° 28' N. long. 

 43° 52' E. 1 observed a long Hack object abeam of the ship's 

 stern on the starboard side, at a distance of about three-quarters 

 of a mile, darting rapidly out of the water and splashing in again 

 with a sound distinctly audible, and advancing nearer and nearer 

 at a rapid pace. In a minute it had advanced to within half a 

 mile, and was distinctly recognisable as the veritable 'sea- 

 serpent.' I shouted out 'Sea-serpent! sea-serpent! call the 

 captain ! ' Dr. C. Hall, the ship's surgeon, who was reading 

 on deck, jumped up in time to see the monster, as did also Miss 

 Greenfield, one of the passengers on board. By this time it was 

 only about 500 yards off, and a little in the rear, owing to the 

 vessel then steaming at tlie rate of about ten knots an hour in a 

 westerly direction. On approaching the wake of the ship the 

 serpent turned its course a little away, and was soon lost to view 

 in the blaze of sunlight reflected on the waves of the sea. So 

 rapid were its movements that when it approached the ship's 

 wake I seized a telescope, but could not catch a view, as it darted 

 rapidly out of the field of the glass before I could see it. I was 

 thus prevented from ascertaining whether it had. scales or not, 

 but the best view of the monster obtainable when it was about 

 three cables' length, that is about 500 yards distant, seemed to 

 sho'v that it was without scales. I cannot, however, speak with 

 certainty. The head and neck, about two feet in diameter, rose 

 out of the water to the height of about twenty or thirty feet, and 

 the monster opened its jaws w ide as it rose, and closed them 

 again as it lowered its head and darted forward for a dive, 



