104 



NA TURE 



[NOVEAIBER 30, 189;; 



tive deck, through the riding bitts on the upper deck, 

 after the tops of these became submerged. 



We thus obtain a total of 1,110 tons of water which 

 entered the ship through the breach made by the col- 

 lision and passed into other compartments, besides those 

 directly laid open to the sea, through open doors, hatches, 

 &c. , a further amount of 100 tons that entered after the 

 tops of the riding bitts became submerged ; and 665 

 tons about which there may be doubt as to the precise 

 positions of the compartments it entered. 



4. The effect of the water thus admitted upon the line of 

 flotation and the stability.— The i,i 10 tons of water above 

 mentioned would, according to the Admiralty calculations, 

 considering its position at the fore-end of the vessel, de- 

 press the bow to the extent of 21 feet, and raise the stern 

 8 feet. This change of Vv^aterline is considered to have 

 necessarily flooded the other compartments, respecting 

 which the direct evidence is doubtful ; and certainly to 

 have filled the boatswain's and carpenter's stores through 

 the riding bitts. The turret ports, and also the door on 

 starboard side, and the ports, in the upper deck battery, 

 would thus be brought under water, and the position of 

 the ship be rendered hopeless. 



Mr. White states, with regard to the stability, that as 

 the Victoria floated before the collision, she had a meta- 

 centric height of 5 feet— z>. the centre of gravity was 5 

 feet below the point at which its righting effect 

 would be nil — and that after the collision, when 

 the bow had sunk deeply and she had heeled considerably 

 — by how much is not said — the metacentric height was 

 reduced to about eight-tenths of a foot. When water had 

 entered the battery and turret through the open door and 

 ports, as observed when the fatal lurch began, the meta- 

 centric height had become altered by the changed con- 

 dition to minus I'S feet ; and the final capsize was 

 inevitable. 



A consideration of the fifth subject treated in these 

 minutes, which is the lessons taught by circumstances 

 connected with the loss — the most important of all for 

 the future— will require an article to itself, and must 

 therefore be postponed till another week. The points 

 mentioned in this connection are : the effect of 

 longitudinal bulkheads upon safety in such circum- 

 stances as are those under discussion ; whether the 

 closing of the battery doors and ports would alone 

 have been sufticient to save the ship ; whether the 

 closing of all water-tight doors and scuttles would have 

 done so ; whether the water-tight doors fitted to the ship 

 were the best for the purpose ; the value of an armour- 

 belt at the ends for the purpose of resisting damage ; 

 and whether the blame rests wholly upon the officers 

 of the Victo7-ia for not knowing how rapidly the ship 

 would be likely to sink when damaged as she was, and for 

 not taking steps sooner to close the water-tight doors 

 and scuttles and prevent the final catastrophe. 



Francis Elgar. 



JUPITER AND HIS RED SPOT. 



JUPITER is now, with his northern declination of 18^ 

 and an equatorial diameter of 48", a very fine object 

 visible above our horizon during more than 15 hours at 

 a time. Thus, on December i he rises at 3h. 7m. and 

 sets at i8h. 23m., shining nearly throughout the long 

 nights now prevailing from a position about (f south- 

 south-west of the Pleiades. 



As an object for telescopic study Jupiter is undoubtedly 

 the most interesting planet of our system. The activity 

 apparent everywhere on his surface, the number and 

 variety of the forms displayed, and the comparative ease 

 with which they may be observed, attest that this object 

 IS practically without a rival, and that the investigation 

 of his phenomena is certain to be productive. 

 NO. 1257, VOL. 49] 



The present time is eminently a suitable one for study- 

 ing his surface markings, and redetermining their proper 

 motions. As the planet's rotation period is less than 10 

 hours, the times of transit of the same spots may some- 

 times be obtained twice on one night, for if a marking 

 crosses, say, 3 hours after the planet's rising, the same 

 object will again reach the central meridian about 2I 

 hours before the planet sets. 



It is well known that the visible surface of Jupiter con- 

 sists of a number of light and dark zones interspersed with 

 irregular forms which exhibit great differences in their 

 rates of velocity. Certain white spots, bordering the 

 equator, move very swiftly, and complete a rotation in 

 considerably less time than the red spot. Some dark 

 spots, which have appeared at various times on a double 

 belt about 25° N. latitude, have moved more rapidly still, 

 and shown a rotation in seven minutes less time than the 

 red spot. But it is a peculiar feature of the different 

 markings that they do not maintain the same rate of 

 motion during their existence ; in fact, a lengthening of 

 period seems to generally affect them. Thus the red 

 spot in 1880 gave a rotation of gh. 55m. 34s., while in re- 

 cent years it has been about Qh. 55m. 41s. The equa- 

 torial white spots, which thirteen years ago had a period 

 of 9h. 50m. 6s., have been gradually moderating their 

 speed until in the last few years their period seems to 

 have been gh. 50m. 30s. It is certain that the various 

 markings are carried along in atmospheric currents, and 

 are subject to remarkable differences, of which we do not 

 comprehend the cause, though we may readily trace the 

 effects. 



The red spot situated in Jupiter's S. hemisphere, and 

 on theboundary of the tropical and temperate zones of the 

 planet, is still perceptible, and it is highly probable that 

 the spot existed long before it first came conspicuously 

 into notice in July, 1878. During the last fifteen years 

 there has been little change either in its oval shape or in 

 its dimensions, though its colour and visibility have suf- 

 fered some trying viscissitudes. It has been successively 

 presented as a brick-red spot, as a faint pink ellipse, as 

 a grey shading, and it is now so feeble that only the out- 

 line of its following side can be distinguished, the preced- 

 ing part of the spot having apparently lost i4:s definite 

 outline. In fact, there seems a prospect of losing the 

 object temporarily if further decadence goes on, but in 

 view of past experience and the probability of recurrence 

 in the Jovian markings, we may certainly expect the spot 

 to reappear, and to present a more conspicuous aspect 

 than it does at the present time. 



The following are some eye-estimates of the transits of 

 the spot during the present apparition ; they were made 

 by Mr. A. Stanley Williams, of Brighton, and by myself 

 at Bristol : — 



The spot therefore transits a few minutes before the 

 zero meridian based on the daily rate, Sjo-2j° ( = 9h. 55ni. 

 4065s. for one rotation). System II. in Mr Marth's 

 ephemerides {Monthly Notices, May, 1893). 



Mr. Williams writes me that he has recently been able 

 to make out the whole outline of the red spot except the 

 preceding end, and on one very favourable night. 



