436 



NA TURE 



[September 3, 1908 



satisfactory, as a prominence 60" in height will remain 

 visible and simply appear to oscillate during a whole rota- 

 tion. It is suggested, however, that satisfactory deter- 

 iDinations of the polar rotation in high latitudes could be 

 made by observing these prominences, whereas the sun- 

 spot observation method cannot be applied and the spectro- 

 scopic method is unsatisfactory. 



Observations of Variable Stars. — The periods and 

 light-changes of several variable stars are discussed in 

 Bulletins Nos. 15 and 16 of the Laws Observatory, Uni- 

 versity of Missouri. No. 15 is devoted to the discussion 

 of 395 observations of the Algol variable RW Monocerotis 

 (24, 1907) made during the period October, 1907, to .'^pril, 

 1908, and a period of 1-9 d. is deduced, the light-changes 

 taking place in 7h. 34m. 



The observations of the long-period Algol variable 

 RZ Ophiuchi are discussed in Bulletin No. 16, and a period 

 of 261-8 d. is found to satisfy them. The other variables, 

 for which only preliminary announcements are given, are 

 RS Bootis, 43.1907 Draconis, 44.1907 Ursje Majoris, and 

 SW .'\ndromeda2 (5, 1907). 



The Influence of the E.\rth's Rotation on the 

 Courses of Rivers. — In a paper published in the Trans- 

 actions of the New Zealand Institute (vol. xxxix., pp. 207- 

 213) Dr. F. W. Hilgendorf discusses some very careful 

 observations made by himself of the possible influence of 

 the earth's rotation on the course of the rivers which flow 

 over the Canterbury Plains, New Zealand. These plains, 

 being of a very homogeneous structure, afford an excel- 

 lent site for the testing of " Ferrel's law " concerning the 

 deflecting force of the earth's rotation, and Dr. Hilgen- 

 dorf succeeds in showing that this deflecting force has, in 

 all probability, been an effective factor in the modification 

 of the banks of the rivers which flow in a N.E.-S.W. 

 direction across the Canterbury plains. 



K Possibly Undiscovered Form of Solar Radiation. 

 — In No. 5 of the Comptes reiidiis (p. 318, vol. cxlvii., 

 .August 3) M. E. Durand-Gr(5ville discussed the secondary 

 twilight and dawn which are observed in the Alps and at 

 other great altitudes, and suggested that reflection of the 

 sunlight from the temperature-reversing layer of the atmo- 

 sphere, discovered by M. Teisserenc de Bort, might account 

 for these phenomena ; but in No. 7 of the Comptes rcndus 

 (.\ugust 17) M. Deslandres offers an alternative suggestion. 

 It is that, in addition to tlie solar radiations which traverse 

 our atmosphere and those ultra-violet radiations which are 

 known to be absorbed bv it, there mav be others, in the 

 further ultra-violet, to which the atmosphere may be trans- 

 parent or which are able to produce a phosphorescence 

 which would account for the secondary illumination of the 

 mountain sides, &-c., after the passing of the ordinary 

 twilight. He further suggests a method whereby the 

 existence of .such radiations mav be demonstrated. 



WELSH ASTRONOMICAL TRADITIONS. 

 T HAVE put together some notes, compiled out of the 

 flotsam and jetsam of Welsh tradition bearing on 

 the continuity of the astronomy of the stone monuments, 

 with the view of finding out how far such traditional 

 materials will enable us to reconstruct, with the aid of 

 the testimony of the monuments themselves, the story 

 of the megalithic period in Britain, the period or periods 

 of the avenue, circle, and cromlech. 



The Testimony of the Bards. 



I have already in these columns claimed for the Gorsedd 

 a continuity of bardic tradition of the greatest value. A 

 more careful study of isolated bardic utterances shows 

 us the bard-astronomer at work in the same capacity as 

 the priest-astronomer of the megalithic period. 



There are two utterances attributed to the bard Taliesin 

 which strongly suggest the use of stars as heralds of 

 sunrise or as clock stars. In suth utterances the note 

 of antiquity is the bard's assumption of exclusive know- 

 ledge of astronomical phenomena. He challenges others 

 to tell him " what hour in the small of the dav (meinddydd) 

 that Cwy was born?" Who Cwy was I know not, 'but 

 the expression should be remembered in discussing Welsh 

 solar heroes. .Again, the bard speaks contemptuously of 



NO. 2027, vol.. 78] 



some who " do not know the point of separation between 

 dewaint (the midnight watch, i to 3) and gwawr (dawn)." 



It should be remembered that the body of tradition we 

 are discussing was once common to the inhabitants of 

 Wales as Goidelic or Irish before it became Welsh. The 

 Irish bard .\mairgen speaks still more definitely of his 

 indispensableness : — 



" Who foretells the ages of the moin (but I)V 

 Who teaches the spot where the sun rests (but 1)? " 



The sun rests at the solstice. People from the earliest 

 times would have noted as much. But the spot — who but 

 the bard knew the solstitial alignment? The words take 

 us back not only to a period before the popular use of a 

 calendar, but also to the time when the almanac for the 

 vear was fixed by direct observation of the solstice sun 

 on the lioriznn ; I'lot that observation of the solstice along 

 the horizon is in itself a proof of antiquity, for a farmer 

 in the parish from which I write still uses that ancient 

 method; but what is curious is the bard's assumption of 

 exclusive credit for the information. 



The leading astronomers of bardic tradition .-ire myth- 

 ical personages. I have elsewhere shown how the lead- 

 ing saints of Wales were regarded as astronomers. But 

 the leading astronomers were the associates of gods, if 

 not gods themselves. " The three sublime astronomers 

 of the Isle of Britain ; — Idris the Giant, Gwydion the son 

 of Don, and Gwyn the son of Nudd. So great was their 

 knowledge of the stars, and of their nature and situation, 

 that they could foretell whatever might be desired to be 

 known to the day of doom." 



Idris is commemorated in the name of the Merioneth- 

 shire mountain, Cadair Idris (Idris's Chair). The Milky 

 Way is called Caer Gwydion (Gwydion 's Encampment). 

 His mother was a goddess. Gwyn, the son of Nudd, is 

 spoken of as the King of the Fairies. His father seems 

 to have been the Welsh Neptune. 



So the remotest antiquity and the place of highest 

 importance is given to astronomy in Welsh or British 

 tradition. 



Holed Stones. 



These arc rather rare monuments. 1 have notes of 

 some in Wales, and I expect, with the growth of interest 

 in the astronoiuical study of such monuments, that more 

 will be brought to light. As Cornish and Scottish tradi- 

 tion shows, such stones were used as charms, a fact 

 which largely explains their present rarity. 



I have not been able to find out the origin of a familiar 

 Cardiganshire expression. When one makes a vain at- 

 tempt to make another person understand or heed what 

 is told him, the speaker or a friend makes the remark. 

 " You might as well say Carreg a ThwU (Stone and 

 Hole) to him." This cryptical Welsh expression Is the 

 name of the famous holed stone of Cornwall, Men-an- 

 Tol, so that the Welsh colloquial Carreg a Thwll may 

 reasonably be supposed to be the holed stone of the mega- 

 lithic period. 



A holed stone figures prominently in one of our oldest 

 written tales, namely, the tale of Math, son of Mathonwy. 

 The stone was on the bank of the river Cynvael in 

 .Ardudwy, a part of Merionethshire, and it was called 

 LIcch Gronw, "the Stone of Gronw or Goronwy." 

 Gronw loved, and was loved by, the wife of Llew Llcw 

 Gyffes, " I.lew of the Un-erring Hand." The woman in- 

 duced her husband to tell her how he might be slain, 

 pretending the most affectionate concern in such an 

 event. He told her gladly, " Not easily can I be slain, 

 except by a wound. .And the spear wherewith I am 

 struck inust be a year in the forming. .And nothing must 

 be done towards it except during the sacrifice on Sundays. 

 I cannot be slain within a house, nor without. I cannot 

 be slain on horseback nor on foot." "Verily," said she, 

 " in what manner then canst thou be slain?" " I will 

 tell thee," said he. " By making a bath for me by the 

 side of the river, and by putting a roof over the cauldron, 

 and thatching it well and tightly, and bringing a buck, 

 and putting it besides the cauldron. Then if I place one 

 foot on the buck's back, and the other on the edge of the 

 cauldron, whosoever strikes me thus will cause my 

 death." 



The woman's paramour toiled for a whole year making 



