May 2, 1872] 



NATURE 



then made, shows that the southern loop of Herschel's 

 Lcniniscate had bulged out into the vacuity, forming an 

 isthmus which trended north and joined the northern 

 loop. The sii-ond drawing, January 1870, shows that 

 within six months this isthmus had detached itself from 

 the north side of the Lemniscate, through 90 ", to form a 

 broader peninsula. The third drawing, April 1870, shows 

 the outline of a gulf or cleft, commencing at H 634. This 



star is one of the " landmarks " described in 1S3S as being 

 " near the margin of the Lemniscate." It is now in mid- 

 channel. These three drawings were made by Mr. Le 

 Seur. No. 4 was made by Mr. McGeorge at the close of 

 December in the same year. It confirms the existence of 

 the Gulf: anotherof the "landmarks," H 6i6, is now nearly 

 clear of nebula. A promontory shown in No. 2 has de- 

 tached itself to form an island of nebula with a starry 

 nucleus. This and the neighbouring outline of the Lem- 

 niscate have the same hard definite outline given by 



PRECEDING 



Herschel ; at one part, however, the outline seems en- 

 croaching upon the Lemniscate, and leaving an oval 

 patch of thinner nebula ; southward the outline seems to 

 be curdling and breaking up. A fifth drawing, which is 

 also here given, was made in June 1871, which amongst 

 other changes shows that the island has shifted ; the 

 nucleus is now detached from it, and proves to be a triple 

 star. 



Mr. McGeorge finds, as Lord Rosse did, that high 

 powers on a good night bring out details of nebula in- 



visible with lower powers. On one occasion he speaks 

 of using 1,300, whose definition, he says, " was magnifi- 

 cent for an hour." He notices a sort of stereoscopic 

 effect which, particularly with the high powers, makes 

 the Lemniscate look "like a huge snowy cave with uneven 

 woolly sides." 



In December 1S69 the spectrum of r; Argus showed 

 bright lines ; but in January 1S71 there was no trace of 

 them ; but Mr. McGeorge thought that with a wide slit 

 he detected absorption bands in the position of the usual 

 nebular lines. Distinct nebulosity v/as then visible round 

 the star, most condensed near it, chiefly in the direction 

 of the Lemniscate. 



It is perhaps unnecessary to remark that Mr. McGeorge 

 has seen nothing in the way of coloured stars at all to be 

 likened to k Crucis ; one or two are reddish. 



It is the intention of the Melbourne astronomers to 

 pursue unremittingly the study of this nebula, which 

 seems already to have given them such remarkable re^ 

 suits. But it is evidently a most laborious task which 

 they have imposed on themselves. At present they are 

 confining their attention to the vicinity of the Lemniscate, 

 but even there the field of labour is immense, for already 

 they have noticed three times as many stars as were seerj 

 by Herschel. 



They have with them the best wishes and sympathy of 

 all astronomers. T. R. ROBlNSON 



Armagh, April 21 



BRITTANY DOLMENS AND LINES 



MR. JAMES FERGUSSON, in his interesting volume 

 on " Rude Stone Monuments in all Countries,"* which 

 will doubtless become a text-book on that section of 

 arch;eology which pertains to Megalithic structures, has 

 made one or two unintentional misstatements, discrepan- 

 cies, or errata, which perhaps he will allow me to correct 

 through your columns, in hopes that they may be in time 

 for the second edition, which is probably called for, if not 

 accomplished. I will state them as briefly as possible. 



I. Carnac (p. 349) : "No stone in the neighbourhood 

 of Carnac is hewn or even fashioned beyond splitting, and 

 no sculptKrcs of any class have been traced" (italics are 

 mine). Will Mr. Fergusson forgive me if I point out that 

 the tumulus of Kercado, situate in the grounds of the 

 Chateau of the same name, and marked in the map of 

 the neighbourhood of Carnac given in his volume Fig. 

 135 as '■ Kercadio Turns. 2" has well marked sculpture on 

 at least three of its stones, one of the figures, viz. that on 

 the undcr-surface of the capstone, being evidently of the 

 same type as the Hafclu-t (?) in the roof of Dol-au- 

 Marchand or Table de Cesar, see Fig. 149 (where by-the- 

 byc I never could make out the so-called plume), and is 

 identical with one in Ec-er-groah (Locmariaker). This 

 tumulus, or dolmen-mound, as I prefer to call it, is 

 much nearer to the lines of Kermario and Kerlescant 

 than Mont S. Michel is to the lines of Menec. I should 

 add that M. Rene Galles figures two of the sculptured 

 stones, but not the hatchet. 



But this is not the sole example of sculptured stones in 

 the neighbourhood of the Carnac amorpholiths. In the 

 curiously arranged dolmens called the " Grcttes de 

 Kerozille," are distinct traces of former sculpture (in 

 which, if I mistake not, some traces of some coloured 

 pigment have been discovered by W. Lukis), of which 

 M. Galles gives but imperfect representations. Doubtless 

 all the stones were covered with similar ornamentation, 

 which has disappeared from the weathering of the stone sur- 

 face. The " Grottes de Kerozille " are situate to the north of 

 Menec, about two miles distance, marked Dols. 1 1 and 

 1 2 in M M. Blair and Ronald's map as given by Fergusson. 

 There are in reality three dolmens, the centre one at right 



^Vidc Nature, Vol. v. p. 386. 



