464 



NATURE 



{Sept. 15, 1 88 J 



should correspond to a real inequality, we should expect it to 

 exhibit a well-defined aid prominent fluctuation, whose depar- 

 tures above and below the mean should be of considerable 

 a nount. 



Suppose, for instance, that we have twenty-four points in our 

 series, aui that we group a long series of temperature observa- 

 tions in rows of twenty four each, the time-distance between two 

 contiguou; members of one row being one hour. The serie-i 

 would thus represent the mean s:)lar day, and we should without 

 d mbt obtain from a final summation of our rows a result exhi- 

 biting a prominent temperature Huctuatijn of a well-detined 

 character, which we might measure (as long as we keep to 

 twenty-four p:)ints) by simply adding together all the departu:es 

 of its various points from the mean, whether these p:)ints lie 

 a'^ovj or below ; in fine, by obtaini ig tlie area of the curve, 

 which is the graphical representatiju of the ineiuahty abjve and 

 below the line of abscisses ta'^en to represent the mean of all the 

 points. Suppose next that, still keeping to rows of twenty-fiur, 

 we should make the time-interval between t.vo contiguous 

 members of a row somewhat different from one hour, whether 

 greater or less, we should no'.v in either case obtain a result 

 exhibiting, when measured as above, a much smaller inequality 

 than that given when the interval was exactly one hour ; and it 

 is even possible tha', if our series of observati ms were sufficiently 

 extensive, we should obtain hardly any traces of an inequality 

 whatever. 



In fine, when each ro.v accurately represented a solar day, the 

 re =ult would be an inequality of large amount ; but when each row 

 represented a period either slightly le<s or greater than a day, the 

 result would be an inequality of saiall amount. This process, as 

 far as I have described it, is not new, iuasaiuch as something of 

 this kind must be pur.-ued in all atle iipts to detect inequalities. 

 In the present in-tince we should by its mean?, after bestowing 

 enormous lab )Ur in variously grouping, in accord mce with a 

 great numb?r of periods taken at smill intervals from e.ich other, 

 obtain definite re-ults. These might be graphically represented 

 in the following manner : — 



The line of abscissa; might be taken to denote the exict values 

 0'' the various periods, forming a time-scale, in fact, while the 

 ordmates might represent the areas or sum nations obtained as 

 above by employing these various peri ids. There would thus 

 be in the case niw used for illustration a very prominent peak, 

 corresponding to twenty-four hours, which would fall off very 

 ra/iidly on either sid;. 



By means of the process now described we should at length, 

 after enormous Ubour, obtain a graphical result, showing the 

 exact position in the time-scale of the observed maxima-m ine- 

 quality. In conjunction with Mr. William Dodgson, I have 

 devised a method by which this labour is very greatly reduced, 

 and the process so modified has been applied by us in order to 

 determine whether th^re be inequrlities of short period in the 

 ob'.erved areas of the sun-spots occurring on the visible he ni- 

 s^iere of the sun. We have detected an inequality of this nature 

 corre-ponding in period to 24'0II days, which, when subjected 

 to a certain purifyi ig treatment, appears to us to exhibit the 

 marks of a true p;riodioity. But it has been suggested by Prof. 

 S.okes that a method of this nature for detecting inequilities 

 m'ght with greater propriety be employed as a crucible fo: 

 test ng the value of some hypothesis introduced into it from 

 without. 



Acting upon this suggestion I have ventured to introduce the 

 planetary hypothe.-i<, anl to ask whether the above sur-spot 

 inequality of short period may not in reality be caused by an 

 intra-Mercurial planet. It is quite easy to put this hypothesis to 

 a test, taking for our guidance the results obtained by the Kcvv 

 observers. For what d i these results exhibit ? In the first place 

 they exhibit the probability of a sun-spot inequality correspond- 

 ing to the period of Mercury round the sun ; and ia the next 

 they exhibit the probibility of similar inequilities corresponding 

 to the synodic period of Mercury and Vejus, and to the synodic 

 ]oeriod of Mercury and Jupiter. 



Now if there be an intra-Mercurial planet of period 24'on 

 days, it will have the following synodic periods : — 



With Mercury 33'02S days. 



With Venus 26'S84 days. 



With Jupiter 24'I45 days. 



In conjunction with Mr. Do Igson I have applied the above 

 method of analysis with the view of ascertaining whether there 

 be well-marked sun-spot inequalitie: nearly corresponding to 

 these periods, and we have obtained the f illowing results : — 



A very prjmi ent Inequality of period ... 32 '955 days. 

 A very prominent inequality of period ... 26"87i days. 

 A less prominent inequality of period .., 24 "142 days. 



It will thus be noticed that there are prominent sun-spot in- 

 equalities, the period of wliich agree very well with the synodic 

 periods of the supposed planet with Mercury, Venus, and 

 Jupiter, more especially if we bear in mind that this is only a 

 first api:/roximation. 



The tes^, however, is not yet conplete. Referring once more 

 to the results of the Kew observers, it will be noticed that we 

 have approximately maxima of sun-spot areas when Mercury 

 and Venus, or when Mercury and Jupiter are in c mjunction. 

 Now if we assume that there is an intra-Mercurial planet of 

 period 24'oii days, we are as yet unable to assign its exact 

 position ill ecliptical longitude at any m iment. We know its 

 period, and we miypre.-ume that it has considerable excentricity, 

 but we know nothing else. We miy, however, assume as most 

 probable that the maximum point of the inequality of period 

 32'955 days co'TCsponds to the conjunction of the planet with 

 Mercury, the maximun point of the inequality of period 26'87I 

 days to its conjunction with Venu=, and the maximum point of 

 the inequxlity of period 24'I42 days to its coijunction with 

 Jupiter. On this assu nptioa, and knowing the average rate of 

 motion of the planet in its orbit, we may deduce appro rciaiately 

 its position at a given epoch independently from each of the 

 three synodic 'periods above mentioied, and these positions 

 ought to agree together, if our hypothesis be correct. 



I have done this approximitely, but am not able to bring 

 exact figures before this meeting. The agreement is as great as 

 can be expected, bearing in mind that we know only the average 

 rate of motion of the planet, and not the v.ariations of its rate, 

 inasmuch as we are ignorant of its excentricity. I think I may 

 s'ate that three independent values of its position corresponding 

 to January I, 1S32, will be obtained, and that the mean difference 

 of a single value from the mean of tlie whole will probably not be 

 mo:e than twenty degrees. It would thus appear from this in- 

 vestigation that the evidence is in favour of the sun-spot in- 

 equality of 24"Oli d-iys being due to an intra-Mercurial planet. 

 Of course a single research o' this nature is in ulicient to esta- 

 blish a theory of this importance, but as there are several short- 

 period so'.ar inequalities, the same metho 1 may be pursued for 

 each, an operation which dejiands nothing but time and labour. 

 It appears to me of great importance that these short- period solar 

 inequilities should be systematically examined after this method. 



The Effects of Gulf Streams upon Clinuites, loy Dr. S. Haugh- 

 ton. — Tlie author said t'lat the Gulf Streim, and its counter 

 current, the Labrador Current, produced important effects upon 

 climate. The northern heinisphere was warmer than the sou'.hern 

 from lat. 0° to lat. 30°, and it was colder than the southern from 

 lat. 40° to 60°. The higher temperature of the southern hemi- 

 sphere in the temperate latitudes w.as explained by the existCi.ce 

 of three gulf streams in that hemisphere, wliile there was only 

 one in the North Atlantic, and a partial one throujh Behring's 

 Straits in the northern hemisphere. The general climatal effect 

 of the Gulf Stream was therefore to make the annual range of 

 temperature le,s, but it had no effect whatever upon summer 

 heat, or upon the fruiting of plants and trees that required a 

 given July temper.iture for reproduction. The January tem- 

 peratures in the'North Atlantic at 70° were raised by the GiJf 

 Stream, whil t the July temperatures remain unaffected. The 

 effect of the cold current;, which were indireclly caused by the 

 warm currents to preserve the proper condition of equilibrium, 

 WIS nothing at all upon the January temp ritues, but they 

 lowered the July temperatures. The effect of the cold water 

 was to lower the July temperature and to leave the January 

 untouched, and the effect of the warm current from the south 

 was to raise January and to leave July unaltered. 



The Pholooraphk Spectrum of Comet B iSSi, by Dr. W. 

 Huggins.— The author seated that in 1S6S he applied the 

 spectroseope to the light of comets, the result of his observa 

 tions being to show the presence of carbon probably in conjuuc 

 tion with hydrogen in the cometary matter. Since then, until 

 the present year, no comet of sufficient brilliancy to admit of 

 observations being made had appeared. On the evening of 

 June 24 last he directed the spectroscope to the head of Cmnet 

 B with an exposure of an hour ; and on the following night he 

 obtained a sec ond phot )graph with an exp osure of an h our and 

 a half. As it happened, the photograph which was the result 

 of the longer period of exposure was the weaker of the two, 

 but, taken together, an examination of the bands confirmed his 



