i66 



HARDWICKE'S SCIENCE-GOSSIP. 



spending to a circumferential contraction of one 

 hundred and twenty miles. This will have to be 

 distributed over widely separate periods, at each of 

 which there is abundant evidence of lateral com- 

 pression. He considers that this shrinkage alone 

 will not account for all the plication or distortion of 

 strata which constitute so important a factor in 

 mountain-making, and he is disposed to supplement 

 it in the way to which allusion has already been 

 made by Mr. Wynne, viz. by considering the effects 

 of the attenuation of strata under superincumbent 

 pressure from deposition in subsiding areas, which 

 involves the thickening, puckering, reduplication, 

 and piling up of strata in regions where pressure has 

 been lessened. It should be noted that, until dis- 

 turbance of " cosmical equilibrium" takes place, 

 mere pressure does not produce metamorphism. 

 The extent of these lateral movements is described, 

 and it is asserted that the theories hitherto adopted 

 to account for plication, &c., are inadequate. The 

 origin of the horizontal movements is further dis- 

 cussed on the hypothesis that solids can flow after 

 the manner of liquids, when they are subjected to 

 sufficient pressure. He considers that the displace- 

 ment in N.W. Scotland may have been initiated by 

 the force due to contraction and accumulating in the 

 crust throughout the periods marked by the deposition 

 of Torridon sandstone and Silurian strata, the ele- 

 ments of movement finding an exit at the ancient 

 Silurian surface. In this case the pile of Silurian 

 strata formerly covering the region now occupied by 

 the North Sea and part of the Atlantic forced the 

 lowest strata to move laterally, the protuberances of 

 the underlying pre-Silurian rocks being also involved 

 in the shearing process. Similar results in other 

 mountain areas. The strata compressed have been 

 greatly attenuated, and extended in proportion ; in 

 this way we may account for the piling up of strata 

 by contortion in certain regions. The connection of 

 this interpretation with Mallet's theory of volcanoes 

 is also indicated, and the author concludes by 

 applying these views to other branches of terrestrial 

 physics. 



NOTES AND QUERIES. 



Weather Cycles. — The computation by cycles 

 or circles is at once the most natural and familiar of 

 methods, but, as regards mensuration, certainly the 

 most abstruse ; hence Solomon piously advocates it, 

 Euclid fails to attain unto it, and our modern alge- 

 braists reach it only by methods of approximation. 

 He who would again wave the sigil and starry wand 

 that invoked earthward that most delightful of en- 

 tities, the wisdom of the universe, let him go and 

 moralize over the concentric circles that strike the 

 gaze on the mist-swept rocks and tombstones of our 

 Celtic lands, which stamp the idea of time in the 

 conventional rings and rays of the tree-stump ; let 

 him ponder how the years of forgotten chieftains were 



chequered with joy and sorrow, and how it is the 

 darkest hour that precedes the dawn ; and let him 

 there and then awake to an impression that the 

 stream of time is full of eddies, and that his own 

 days and years are spinning on in circles. Hardly a 

 trio of centuries has gone since there existed in this 

 country a much-abused faith in climatical years, and 

 a belief in the luck and ill-luck of the sevens and the 

 nines ; and now the lamp of Science aids us to seek 

 the burden of the years in those eleven-year periods 

 in which the sun runs thmugh its appointed cycles of 

 spots, and the reason of our weeks in the proverbial 

 changes of weather. In dealing with a venerable 

 idea which is public property, I do not desire to 

 grapple with those who find a reason to suppose that 

 the weather is dependent upon the moon or the 

 planets in their courses, though for myself I believe 

 it to be coincident with the sun spots in their fluctua- 

 tions and movement ; and though I further find a 

 more decided proof in statistics that leads me to con- 

 clude that there originates a cyclonic disturbance in 

 the earth's atmosphere every twenty-five days on the 

 average, with a tendency in blows to recur every 

 eighth or ninth day ; upon which premises I have 

 even ventured to construct an index. This as it may 

 be, there remains ample reason in the weather cycles 

 to explain that notion of dearth and plenty which, 

 according to the Jubilee or Jewish seven year calcula- 

 tion, recurred every 7, 14, 21, 28, 35, 42, 49, and 50 

 years, and, according to modern astronomers, may 

 arise every 8, 11, 19, 22, 30, 33, 41, 44, and 52 years ; 

 the voice of joy and mourning. Here is a marked 

 similarity of figures, and, on the best authority, a 

 mere question of an ancient and modern astronomical 

 unit, 7 or II, for the latter of which there is a good 

 reason. As regards the weekly changes, we may 

 conclude that they have been already considered by 

 King Solomon, for he says, " Give a portion to seven 

 and also unto eight, for thou knowest not what evil 

 shall be upon the earth." — A. H, Sxointon. 



Clutches of Birds' Eggs. — With great satis- 

 faction I observe that attention is being drawn to the 

 modern fashion of collecting birds' eggs in clutches. 

 I have repeatedly heard all the arguments that can 

 be advanced in favour of the new system, and am 

 still unconvinced of any superiority over the old 

 style. The argument advanced by Mr. Nunn in 

 your June number is easily answered. All collectors 

 are aware that frequently one egg of a clutch varies 

 widely from the rest. But supposing the rest are 

 normal, why take them ? Would not a note accom- 

 panying the peculiar variety be enough ? And 

 should your correspondent's surmise prove correct, 

 that the odd egg is usually unfertile, the cabinet 

 could be enriched by a curious specimen without any 

 loss to the bird-life of the country. In passing, I 

 may say I have no belief in this theory of some 

 relation between the colour and fertility of eggs, as I 

 have frequently found nests in which the aberrant 

 egg was fertile, and other cases in which normal 

 eggs were unfertile without displaying any symptom 

 of their addled state externally. The most fallacious 

 argument under which these nest robbers shelter 

 themselves is, that the bird will rear another clutch, 

 and can as easily do that as bring up a part only 

 of their family. Probably your correspondent is un- 

 married, and therefore has not had an opportunity of 

 judging of the difference between rearing a large and 

 small family. But should some " clutch collector " 

 come across the second brood, what then ? Mr. 

 Young has adduced a striking example in two recent 

 numbers of SciENCE-Gossir, where we find it re- 

 ported that a pair of ravens have four times this 



