Nov., 1904. 



KNOWLEDGE & SCIENTIFIC NEWS. 



265 



Sunspot VaLrioLtion irv 

 LoLtitvide. 



By Wiii.iAM J. S. LocKVEK, M.A., I'h.I). 

 From a study of the facts regarding the dislrilnition 

 in latitude of spots on the surface of the sun, Mr. 

 Maunder and I e\idently hold different opinions, and 1 

 do not think that a further discussion ol the subject 

 will tend either to change them or ad\ance our know- 

 ledge of this spot distribution. 



Perhaps I may, however, be permitted to make a 

 final reply to some of Mr. Maunder's remarks in your 

 October issue. 



-Speaking of the term "spot-activity track," Mr. 

 .M.iunder says: " It is abinidantiy clear that he did 

 intend to intimate by it that the sjjots were gathered 

 together in certain districts or regions, separated from 

 each other by broad, barren intervals, and that these 

 districts, rich in spots, moved continuously dow invar_ds 

 towards the cc|u;itor." (Ihe italics are mine.) 



I am afraid Mr. Maunder cannot have re.id my 

 paper thoroughly, or even carefully looked at the 

 figure on page 144. 



In the paper I have staled (p. 145), " in tiiis way it 

 was possible to trace the varying positions, as regards 

 changes of latitude, of the centres of action or maxima 

 points of the curves, from year to year . . ." 



And on page 147 the term " spot-acti\ ity tracks " is 

 applied " simply to the changes of positions of the 

 regions in which they (the spots) are most numerous." 



I have nowhere mentioned that these regions were 

 separated from each other by " broad, barren inter- 

 vals," as he calls them, for such a statement would be 

 against all the facts ; if the text and diagrams be con- 

 sulted, no such general deduction can possibly be made 

 with accuracy. 



It w-as to make this, among other points, clear, that 

 Fig. I, p. 181, in the .August number of this journal 

 was inserted, where it will be seen that the portions of 

 the curves between the individual maxima do not reach 

 down to the zero line, which they should do if those 

 regions were "broad, barren intervals." If Mr. 

 Maunder considers that these " broad, barren inter- 

 vals " are suggested on the curves marked .'\ in plates 

 4 and 5 of my paper, then this is another indication 

 that he has not read it carefully before criticising it. 

 In describing these curves to which reference has just 

 been made, I pointed out (p. 146) that they " were 

 proportionally thickened to indicate approximately the 

 relative amount of spotted area at these centres of action, 

 or, in other words, the heights of the maxima points 

 on the vearly curves. These curves thus indicate for 

 each year the positions, as regards latitude, of the 

 particular zones in which the centres of spot-activity 

 occur. " 



Mr. Maunder in his letter states further that he 

 " explained therein the nature of the mistake which 

 Dr. Lockyer had made with regard to the maxima on 

 which he based his paper, and that his method of jf)in- 

 ing them up so as t') show apparent lines of drift was 

 not only purely arbitrary, but was often against very 

 distinct and positive evidence." 



I am afraid, however, I cannot accept this explana- 

 tion which he has so gratuitously offered. To my mind 

 the larger the sunspot or its greater extent in latitude, 

 and the longer it exists, the more important becomes 

 the region in which such a disturbance takes place. 

 Mr. Maunder evidentiv thinks otherwise. 



Ill the imtc uu |).ii;c i ^^) of this journal, which fi'om 

 its general tone I assume Mr. Maunder wrote, it is 

 stated th.'it " Mr. Maimder showed that the (Greenwich 

 Simspot Results for the last 30 years fully confirmed 

 Spoier's Law," yet Mr. Mainuler now claims priority 

 for a statement I have made which is not in strict 

 accord with this law. 



.'\ccording to Sporer's Law, formulated about iSHo, 

 the highest spot latitudes occur about the time of sun- 

 sjiot minimum. In my paper I suggested that this l.iw 

 needed modification bec.iuse an analysis of the facts 

 indicated that : — 



[a). Outbursts of spots in high latitudes are not 

 restricted simply to the epochs at or riboul a 

 sunspot minimum, but occur even up to the 

 time of sunspot maximum. 

 (/'). The spots tended to reach their highest lati- 

 tudes at or about sunspot maximum, 

 [c). From sunspot maximiun until about the 

 following minimum high latitude spots were 

 for the most i)art consi)icuous by their 

 absence. 



The ;ibo\e three deductions, all ol which can he 

 gathered from an intelligent exnmin;ilion of the plates 

 accompanying niv paper, show that the appearance of 

 spots in high latitudes he.irs a f.iirlv definite relation 

 to the simspot maxim;i and minima epochs. 



Mr. Maunder refers to a p.-iper (Monthly t\'ol. May, 

 1903) prepared by him by the desire of the Astronomer 

 Royal, in which his deduction as regards the occiuTenci- 

 of high latitude spots is as follows : — 



" Taking them as a class by themselves, they were 

 seen irregul.irly, appearing at times which did not 

 seem to bear .any fixed relation to any one of the four 

 chief stages of the sunspot cycle — minimum, increase, 

 maximum, and decline. . . ." 



.Since Mr. Maunder's "brief preliminary text," to 

 which he refers, suggests an irregularity of appearance 

 of high latitude spots, and my statement restricts this 

 time of appearance from about a sunspot minimum to 

 about a sunspot maximum at which the highest lati- 

 tudes are attained, I fail to see how he can " claim " 

 the priority of the deduction I made. 



Mr. Maunder has further forgotten to mention one 

 of the conclusions, corrobor.-iting my statement, to 

 which F'ather Cortie recently arrived, namely : — 



" Cireater disturbances are most prevalent in high 

 Latitudes at or near the times of solar maximum . ." 

 (Monthly Not., Vol. 64, p. 76O.) 



Would not Father Cortie also ha\e referred to Mr. 

 Maunder's " brief preliminary text " if a statement 

 equivalent to the abo\e had been pre\iously published 

 by Mr. NLaunder? 



In conclusion I may be permitted to add that it was 

 very far from my thoughts to take the " results " of 

 .Mr. Maimdcr's paper as he states in his last letter. 

 Researches at the .Solar Physics Observatory rendered 

 it necessary to make a detailed study of simspot ob- 

 servations, and use was made, bv permission of the 

 .Astronomer Royal, of data (which at the request 

 of the .Solar Physics Observatory had been brought 

 up to date) and not of results derived by Mr. 

 Maunder. 



It seems necessary to point out to Mr. Maunder that 

 observations are made, collected, and reduced at public 

 expense, in order that they may be studied by those 

 who wish to utilise them for the purposes of science, 

 and are not the " property "of any computer or assist- 

 ant who inay have been charged with the duty of pre- 

 paring them for publication. 



