KNowi.i.Dr.i:. 



Fkiihi'auv. 1012. 



iictinn (if Sun spots, and 1)\ tlic friction producinf,' 

 tliL- flasliis of li},'l't seen on tlie solar surfacr. 



The coincidences of these two variables is very 

 striking as shown by the accompanying diagram 

 (Figure 55). CiearK' it is conclusively proven. liartli 

 auroras are also associated with the same phenomena. 



CONCt.lISION. 



The Sun presents too stupendous a series of 

 problems to be effectively dealt with in a single 

 article. The foregoing ideas are offered as preliininar\ 

 suggestions for the solution of some of them. 

 Sufficient has been said to show the complexity, the 

 wonder and beaut\' of the subject, and also its basic 

 im|)ortance. Magnificent work is now being done 

 by workers in many fertile fields of its varied 

 researches. Some are taking photographs in special 



wave-lengths of varied elements, chiefly calcium and 

 hydrogen. It will be seen by the accompanying 

 pictures what wonderful information they afford of 

 the ensphering sf)lar surfaces. How clearly they 

 show the r\<lonic increase with altitude. W'c want 

 all the inff)rmation we can get. And the proposed 

 solar observator\' for Australasia should soon be a 

 realized fact. For the wondrous skies of the 

 .\nti|)odes are singularly suitable, and the Sun is 

 there showing his brightest when night reigns in 

 b-ngland. 



I hope that those about to be engaged in work 

 connected with the coming eclipses will see if any of 

 the above suggestions may serve as working hypotheses 

 to guide their imjiortant researches. 



In the next article I shall give some tentative ideas 

 regarding the character of Comets. 



THI". I'iXrs AX!) S1I.\|)I-.S OF AlTrMX WOODS. 

 Bv P. O. KE1:GAN, LL.l). 



Several views, hypotheses, or opinions, based on 

 experimental research, or otherwise, have been 

 broached regarding the origin or production of the 

 red. vellow and brown tints and shades exhibited 

 by our forest leaves in autumn. The cjuestion stands 

 next in interest, perhaps, to the cognate one as to 

 the origin of the floral pigments, and, like the latter, 

 it can be elucidated only by a consideration of the 

 chemical facts which lead to an understanding of 

 the phvsiological processes involved. That there is 

 some intimate connection between the actual con- 

 dition of vitality of the leaf at the autumnal period. 

 and the particular tint or shade which it will then 

 exhibit, can, I think, be fully demonstrated. There 

 are. fortunately, two indisputable tests or indications 

 detectable by chemical analysis which assure us to a 

 certainty as respects this condition of vegetative 

 activity. In the first place, we may compare the 

 relative proportions of the special ministers of 

 protoplasmic activity, viz., the albuminoids, in 

 summer and in autumn: and secondly, by comparing 

 the relative quantities of certain of the mineral matters 

 (ash) present therein at the two stated periods respec- 

 tively. Let it be observed at once that when the per- 

 centage proportion of albuminoid found in tiic 

 autumn leaf is considerably less than that found 

 in a similar leaf in .summer, the conclusion may be 

 drawn that the vitality thereof is sustained up till a 

 late period : and when the case is reversed the infer- 

 ence is that there has been an early exhaustion of the 

 vegetative activity. In other words, in the former case 

 the albuminoids are mostly used up. and in the latter 

 case they remain stored up in some inactive form or 

 other. Similarly, also, with respect to the silica in 

 the ash ; an autumn leaf containing little silica is 

 still alive, as it were, and vice versa. The following 

 table is given in illustration of these facts: — 



(To /)c' c 



Li;.\vi;s Red in Autumn. 



The fi};ures represent the percentages of albuminoid in the dried leaf. 



It may also be noted that, in certain years and 

 localities, oaks and beeches exhibit a very decent 

 show of red. while, at the same time, the percentage 

 of albuminoid falls below the normal, although that 

 of silica may still remain pretty high, but in these 

 instances the quantity of total ash is always low 

 (.about six per cent, in dry). Nevertheless, on a 

 general review of the phenomena, it apjiears certain 

 that where the protoplasmic albuminoid remains 

 active till late, i.e., in a more or less labile and 

 soluble condition, the encroachment of silica upon 

 the foliar tissues is checked, and the leaf assumes a 

 bright red tint. The ]ihysiological processes are 

 still vigoroush" sustained, and the cells retain both 

 their water and their volume : but deassimilation 

 predominates over assimilation, and hence there is 

 more oxidation than reduction, more analvsis than 

 svnthesis, a destruction of chloroph\ll and a depletion 

 of starch, a powerful accumulation of saccharine 

 matters and glucosides : and hnalh'. an especially 

 strong and distinctive appearance of that crowning 

 product of the foliar laboratory, named ervthrophyll. 



()»;//;/;a'(/.> 



