192 



NA rURE 



[Jan 4, 187: 



though of unequal 'merit. Any of them would make a charming 

 present for an intelligent child. 



On November 10 there was an earthqunke in Salvador in 

 Central America, and on the 1 2th a stronger one. At Simla there 

 was an earthquake on \ovember 25. Two sharp shocks were 

 felt at Macedonia on November 26 at u r.M. 



What is called the Iquique earthquake took place on Oct. S, 

 at I A.M. Although alarming and lasting two minutes, with a 

 terrible shaking of the earth, first vertical and afterwards oscilla- 

 tory, it did no damage at Iquique. It was however, simulta- 

 neously felt elsewhere, and has destroyed or damaged the towns 

 of Tarapaca, Usmagama, Guasquina, Pica, MatiUa, and the 

 village of Pachica. Some persons were injured, but only two 

 lost their lives. 



At a recent meeting of the Scientific Committee of the Horti- 

 cultural Society, a letter was read from Mr. Anderson-Henry 

 (printed in the Gardeners Chronicle for Dec. 9), in which he gave 

 some curious results of his observations on climbing jilants. 

 Mr. Henry stated that certain climbers evince a partiality for 

 some other species, stretching out their tendrils or branches so 

 as to come in contact with them, while to other species they have 

 as strong .an aversion, avoiding them and never touching them, 

 though they may run up the same wall side by side. The subject 

 is a curious one, and deserves further investigation. 



"The Fortunate Isles," translated from the French of Ogier, 

 is an account of the Canaries. A chapter on the celebrated 

 dragon tree contains the two jussages here transcribed. Written 

 apparently in sober earnest, they are, perhaps, not the least re- 

 markable contribution to the scientific literature of the year now 

 ended. " It is an undoubted fact that before the great Mediter- 

 ranean deluge, and to a certain point even after it, strange crea- 

 tures brought forth in transitional period-:, inhabited the marshy 

 grounds or those shallow seas which still remained warm. This 

 epoch, called by modern geologists the Reptile Period, produced 

 creatures belonging at once to the animal, vegetable, and mineral 

 kingdoms, or to two only ; monstrous products of creative 

 forces ; birds, quadrupeds, fish, plants, rep.ile.s, all at once, 

 either united or distinct ; the greater number of these have 



been restored for us by geologists The dragon 



has existed. The first men saw the last survivors of these 

 prodigious creatures, and the memory of them has been pre- 

 served. The struggles of mankind with the mighty creatures 

 which overran the earth must have been terrible. The excessive 

 alarm of men possessing no weapons in the first age?, gave rise 

 to the tr.aditions of formiiable beings attacking mankind and 

 destroved by the demi-gods, strong and brave men." 



From the Elizabctli Doily youriml of New Jersey of Nov. 

 28 we have a marvellous story of a carrier pigeon, which we 

 commend to the notice of Mr. Tege!ir:eier. It performed the 

 journey from .Sopus Farm, Warren Co., N.J. , to Sai dusky 

 Ohio, a distance of 400 miles, in exactly an hour, and its condi 

 tion on its arrival at the latter place is thus described ; — ''I found 

 the greatest excitem.ent had followed the arrival of the pigeon. 

 Mr. Smythe told me that at precisely two o'clock the bird came 

 like an arrow into his house. His movement was more bke a 

 blue streak than a well-defined bird. He seemed but little ex 

 hausted, although nearly all the feathers were off his body, except 

 the small patch held on Iris back by the gutta-percha which 

 fastened the note. A few miles more would have worn every 

 feather from his wings, and then he would have to depend upon 

 the momentum already acquired to carry him on his journey^ 

 and to steer by a tailless rump, and perhaps be killed in attemiit- 

 ing to alight." No wonder the owner offers to match this 

 pigeon "when he has grown a new suit of feathers" for 1,000 

 dollars against any carrier pigeon that has not done this distance 

 in an equal time. 



PERIODICITY OF SUN-SPOTS* 



TX the short account of some recent investigations by Prof. 

 -'■ Wolf and M. l^'ritz on .Sun-spot phenomena, which has 

 been published lately in the " Proceedings of the Royal Society" 

 (No. 127, 1871), it was pointed out that some of Wolf's conclu- 

 sions were not quite borne out by the results which we have 

 given in our last paper on Solar Physics in the Philosophical 

 Transactions for 1S70, pp. 389-496. A closer inquiry into the 

 cause of this discrepancy has led us to what appears a definite 

 law, connecting numerically the two branches of the periodic 

 sun spot cur\'e, viz., the time during which there is a regular 

 diminution of spot-production, and the time during which there is 

 a constant increase. 



It will be well, for the sake of clearness, to allude here again, 

 as briefly .as possible, to Prof. Wolfs results before stating those 

 at which we have arrived. 



Prof. Wolf ha; previously devoted the greater part of his 

 laborious researches to a precise determination of the mean 

 length of the whole sun-spot period, but latterly he has justly 

 recognised the importance of obtaining some knowledge of the 

 average character of the periodic increase and decrease. Hence 

 he has, as far as he has been able to do so by existing series of 

 observations, and his peculiar and ingenious method of rendering 

 observations made at different times and by different observers 

 comparable with each other, endeavoured to investigate more 

 closely the nature of the periodic sun-spot curve, by tabulating 

 and graphically representing the monthly means taken during 

 two and a half years before and after the minimum, and applying 

 this method to five distinct minimum epochs, which he has fixed 

 by the following years : — 



1823 2 



1833-8 



1844 o 



18562 



1867-2 

 In a table he gives Iheir mean numbers, expressing the 

 solar activity, arranged in various columns ; and arrives at the 

 following results : — 



(i) It is shown now with greater precision than was previously 

 possible, that the curve of sun-spots ascends with greater 

 rapidity than it descends. The fact is shown in the subjoined 

 diagram, which it may be of interest to compare with the curves 

 given previously by ourselves in the above-mentioned place. 

 The zero-pomt in this diagram corresponds to the minimum of 

 each period ; the abscissn? give the time before and after it, viz., 

 two and a half years, or thirty months ; the ordinates express 

 the amount of spot-production in numbers of an arbitrary scale. 

 The two finely dotted curves are intended to show the actual 

 character of a portion of two periods only, viz.. those which 

 had their minima in i823"2 and 18672; the strongly dotted 

 curve, however, gives the mean of all periods (five) over which 

 the investigation extends. 



(2) DenoLing by x the number of years during which the curve 

 ascends, and presuming that the behaviour is approximately the 

 same througnout the whole period of ii'i years as during the five 

 years investigated, we have the proportion 

 .1: II'I - .V : : I : 2, 

 whence .v = 37, 



or the average duration of an ascent is 37 years, that of a descent 

 7 '4 years. 

 (31 The character of a single period may essentially differ 



from the mean, but on the whole it appears that a j j ,1 



descent correspunds to a , , , ascent. Thus the mini- 



mum of 1844 'o behaved very normally ; but that of i856'2, and 

 still more that of 1823*2, shown in the following diagram, presents 

 a retarded ascent and descent ; on the other hand, the minimum 

 of i833'S, and still more in that of lS67'2, also -hown in the 

 diagram, both ascent and descent are accelerated. 



Finally Prof. Wolf arranged in the manner shown in the 

 following table the successive minima and maxima, in order to 

 arrive at some generalisation which might emble him to foretell 

 the general character and length of a future period. Taking ihe 

 absolute differences in time of every two successive maxima, and 



* Abstract of paper read before tbe Royaf Society December 21, 1S71. 

 " On some recent Researches in Solar Physics, and a Law regulating the 

 time of duration of the Sun-spot Period." By Warren De La Rue, F.R.S., 

 Balfour Stewart, F.R.S., and Benjamin Loewy, F.R.A.S, 



