34 



NATURE 



{Nov. II, 1880 



continuance of disturbance tlie oscillations of the magnets seem 

 to be so locally modified that it becomes difficult to trace corre- 

 spondence : some movements appear to correspond, and some 

 not. A strongly-marked bend in the trace at one place may 

 appear, as it were, stunted in that at the other place, or may not 

 be perceptible at all. The disturbances appear to die out at 

 pretty much the same time at both places. All this confirms 

 very much what Mr. Whipple has already pointed out as regards 

 Melbourne (NATURE, vol. xxii. p. 55S). 



M. Dechevren?, in some remarks which accompany the sheet 

 of curves, notes that the disturbance of August 11-14 '^ the 

 greatest experienced since the establishment of photographic 

 registration at Zi-ka-wei in the year 1S77, and he considers that 

 the changes then observed (those of vertical force included, of 

 which he gives no curves) are similar to such as would be pro- 

 duced by a powerful magnet placed in a certain defined position. 

 It may perhaps be here pointed out that the results given by the 

 Astronomer-Royal in his paper, "First Analysis of One Hun- 

 dred and Seventy-seven Magnetic Storms" (P/iil. Trans, for 

 1863) appear to give no support to a theory of this kind, and 

 indeed seem conclusively to show that at Greenwich the ob- 

 served disturbances cannot be accounted for in any such way. 



It should be added that M. Dechevrens reports also that strong 

 earth currents were experienced on August 11 and 12 on the 

 submarine telegraph lines connecting Shanghai, with Nagasaki 

 and with Hong-Kong, as well as on the land lines in Japan, so 

 much so that correspondence was frequently interrupted, but 

 that no interruption appears to have been experienced on the 

 occasion of the generally smaller magnetic disturbance of 

 August 18. William Ellis 



Royal Observatory, Greenwich, November 6 



Meteor 



A VERY large and brilliant meteor was observed here at 6h. 

 41m. p.m. G.M.T., on November S. Its size was at least equ.al 

 to one-fourth of that of the full moon, and it lit up the whole 

 garden for about a second and a half. It was pear-shaped. The 

 colour was white, and left behind it a pale red train. Its path 

 was from a point half-way between a and 8 Persei to 3" above 

 V Urs^e Majoris. The sky was rather hazv at the time. 



Stonyhurst Observatory, November 9 S. J. Perry 



Condition of Jupiter 



On the evening of the 2nd I had a fine view of Jupiter with 

 my 6-inch Cook's equatorial. The general appearance of the 

 planet was remarkable for the bright colouring of the belts and 

 of the red spot, a circumstance strongly noted by a gentleman 

 who was observing with me, and who had not seen the planet 

 for some time. 



I could not however trace the usual white ring round the red 

 spot. Below the red equatorial belt was a row of four or five 

 small irregularly-shaptd spots, nearly black in tint, and resem- 

 bling sun-spots seen under a low power. 



These dark spots seem now affecting Jupiter's surface in 

 several parts, and are certainly not usual to it. About gh. 26m. 

 Satellite I. was occulted. I watched it gradually coming to 

 contact, and at la^t it seemed to advance on the face of the 

 planet, at least one-half of its diameter appearing to project 

 thereon. It then faded out gradually. 



September 3, 1879, at 9b. Sm., with the same instrument 

 Satellite III. reappearing after occultation, was slightly (but 

 certainly) projected on to the disk of the planet. It will be 

 interesting to notice whether the present condition of Jupiter 

 will be accompanied by more than ordinary displays of auror.x, 

 of which symptoms have already appeared. 



Guildown, November 6 J. Rand Capron 



P.S. — Since writing the above accounts reach me of aurora; 

 at Brighton on the 3rd and in the Orkneys on the 4th instant. 



Vox Angelica 

 Many of your readers may be acquainted with the nature of 

 the Vox Angelica stop on a good organ. It consists of two 

 ranks of pipes of small scale and delicate quality of tone, one of 

 which is tuned slighlly sharp, so that a wavy (hence called Uttda 

 Maris) sound is produced. Now it is possible to obtain very similar 

 effects on an ordinary Estey American organ. Given the viola 

 and violetta stops to be drawn out, wrap a band of india-rubber 



(an ordinary elastic band does very well) round the neck of the 

 viola stop so that it cannot return completely home, on moderate 

 pre>sure, and allowing a fraction of an inch to intervene between 

 its true final position when inactive ; beats will be heard of 

 intensity depending upon the deviation from complete occlusion 

 of this stop. The nearer the viola stop is to occlusion the more 

 rapid the beats ; but it is undesirable to obtain rapidity, as the 

 lower notes are too prominently out of tune in this case. Any- 

 body can, by experiment, determine the proper amount of devia- 

 tion to be employed, and having done this the effect is remark- 

 ably good. On an Estey, the two stops mentioned are the only 

 admissible ones for such an experiment, from consideration of 

 overtones. No doubt some of your readers may adopt a more 

 elaborate and convenient method of regulating the deviation than 

 by elastic bands, after some experiments. It may seem a paradox 

 to obtain beautiful c ncordant effects by the use of discordant 

 vibrational relations, but it is undeniable that on a first-class 

 organ the Voix Celeste, or Vox Angelica, or Unda Maris, is a most 

 beautiful stop, and is capable of producing perfect con sordini 

 effects. George Rayleigh Vicars 



Woodville House, Rugby, November 3 



Solids and Liquids at High Temperatures 



Some years ago I made an investigation much simpler but 

 somewhat similar to that referred to by Prof. Carnelley in 

 Nature, vol. xxii. p. 435. An account of the experiments 

 then made was communicated to the Royal Scottish Society of 

 Arts, 1874-75. O"^ of ''ifi results of that investigation was 

 that while we do know something about the temperatures at 

 which different forms of matter change from one state to another 

 when a " free surface" \% present, yet we are utterly ignorant 

 of the temperature at which that change will take place when 

 no "free surface" is present. It will be necessary here to ex- 

 plain that a ''free surface" is any surface of the body under 

 examination at which it is free to change its state. A surface of 

 water, for instance, in contact with its own vapour is a "free 

 surface " for the water passing into the gaseous state. The sur- 

 face of a piece of ice in water, again, is a "free surface" at 

 which the water may freeze or the ice may melt. And what are 

 known as the freezing, melting, and boiling points of water are 

 the temperatures at which these changes take place when such 

 "free surfaces" zxQ \>rt:^ent. As to what the freezing, melting, 

 and boiling points are when these "free surfaces" are absent, 

 we have at present no knowledge whatever. All we know is that 

 the freezing point is lowei-, and the "melting" and "boiling 

 points " are higher, than when "free surfaces " are present. 



The fir.-t of these points is too w ell known to be referred to 

 here. The last point was illustrated in the paper referred to by 

 an experiment in which water w-as heated in a metal vessel under 

 atmospheric pressure to a temperature far above the "boiling 

 point, when the water exploded and violently ejected itself 

 from the vessel. The superheating of the water was accom- 

 plished by carefully excluding all "free surfaces" by bringing 

 the water into as perfect contact with the metal of the vessel as 

 possible. 



Many experiments were also made to get direct and thermo- 

 melric experimental illustration of the existence of ice at a 

 temperature above the "melting point," but no satisfactory- 

 illustrations were got, on account of the great difficulty of 

 getting quit of "free surfaces." Of course so long as there 

 existed a "free surface" at the surface of contact of the ice with 

 the thermometer, the temperature at that part could not ri-e 

 above the " melting point." It was however shown by indirect 

 evidence that ice may exist at a temperature above the " freezing 

 point " by referring to the h ell-known and beautiful experiment: 

 of passing a beam of light through a block of ice. When this 

 is done with the aid of proyier apparatus it is seen that the heat 

 of the ray is absorbed by the ice, and that melting takes place at 

 different points inside the block. Now the presumption is that 

 the heat is absorbed at all puints inside the block, but as the 

 melting only takes place at certain points the heat absorbed 

 where there is no melting must raise the temperature of the ice at 

 those points above the " melting point," and theheat there ab- 

 sorbed by the ice will be conducted to the "free surfaces" where 

 it is spent in melting the ice. 



Now though I was perfectly prepared to find that Prof. Car- 

 nelley had succeeded in heating the inside of a block of ice to a 

 temperature above the "melting-point," I certainly did not 

 expect so high a temperature as his experiments indicate to be 



