Nov. 17, 1887] 



NATURE 



61 



In Comets h, 1881, and c, 1882, the only lines recorded were 

 magnesium b ; but, as before, the apparent absence of other lines 

 might be due to continuous spectrum. 



Of the five bands shown in Huggins's photograph of the spec- 

 trum of Comet Wells, taken with a wide slit, no less than three 

 agree fairly in position with three lines seen in the spectra of 

 meteorites. The wave-lengths of these are 4253, 4412, and 

 4769, and it is interesting to note that, so far, the origin of 

 these lines is undetermined. The two remaining bands are at 

 wave-lengths 4507 and 4634. 



It is seen, then, that the spectraof comets— when their internal 

 motions are relatively either slow or fast, and when therefore 

 the number of collisions, and with them the heat of the stones in 

 collision, will vary extremely— resemble the spectra of meteorites 

 seen in glow tubes, 



(7) "Stars "with flutings which have been observed in the 

 laboratory and in luminous meteors and comets. 



The most prominent bright flutings of carbon are not only 

 observed in luminous meteors and comets, but in stars of 

 Class 1 1 1, a, and in some "Novas," notably Nova Orionis. 

 So far, then, these bodies may in a certain measure be classed 

 with luminous meteors and comets. But there is an important 

 difference in the phenomena, for we have absorption as well as 

 radiation. The discussion shows that the dark (or absorbing) 

 flutings in these bodies are partly due to the absorption of light 

 by the most prominent flutings of Mn and Zn, seen at low 

 temperatures. This inquiry is being continued. 



We have, then, in these bodies a spectrum integrating the 

 radiation of carbon and the absorption of Mn and Zn vapour. 



The law of parsimony compels us to ascribe the bright fluting 

 of carbon in these stars to the same cause as that at work in 

 comets, where we know it is produced by the vapours between 

 the individual meteorites or repelled from them. 



Hence we are led to conclude that the absorotion pheno- 

 mena are produced by the incandescent vapour surrounding the 

 individual meteorites which have been rendered intensely hot by 

 collisions. 



These stars, therefore, are not masses of vapour like our sun, 

 but clouds of incandescent stones. 



We have here probably the first stage of meteoritic conden'^a- 

 'ion, J. Norman Lockyer. 



( To be continued.') 



FAIRY-RINGS. 



nr H E rains have come, and we have heard from all sides 

 -»• of the prolific crops of mushrooms and toadstools 

 —paddock-stools, as they are termed in some northern 

 districts— which have been sprin<,nng up in the meadows 

 and woods of England, Wales, and Scotland. Not only is 

 surprise evinced at the marvellously rapid up-growth of 

 these fungi, for the popular mind may well be amazed at 

 that until a knowledge of the biology of these plants is 

 more universal, but country people and dwellers in towns 

 alike exclaim at certain other phenomena associated with 

 their growth in the fields, and at none, perhaps, so much as 

 what have been known from of old as " Fairy-rings " in 

 England, Hexenri7tge and Cerdes de sorcieres on the Con- 

 tinent, Now fairy-rings, like very many other poetical 

 objects, have of late years undergone the process of 

 being explained away to an extent which, although it in 

 no way removes the beauty from them, demands from 

 us an admiration of a more stimulating and healthful 

 character than the old awe which they inspired was 

 capable of producing. 



Disbelief prevails regarding Prospero and the beings 

 that 



and 



" By moonshine do the green sour ringlets make, 

 Whereof the ewe not bites ; " 



" whose pastime 

 Is to make midnight mushrooms." 



Fairy-rings are more or less regular and complete 

 rings of grass, sharply distinguished from the ordinary 

 grass surrounding them by means of their darker hue. 



more luxuriant growth, and other characters ; in spring 

 or autumn they are to be found with vigorous growths of 

 mushrooms or toadstools springing from their outer 

 margins, and the centre of the ring is often marked by a 

 very poor crop of withered-looking herbage. 



Before proceeding to give an account of the modern 

 explanation of these remarkable objects, a few statements 

 may be made as to their sizes, structure, and occurrence. 



They are not always complete or regular rings, but 

 may be parts of circles or ovals, or mere wavy strips. 

 Nor are they always provided with the outer belt of 

 fungi, though the rule is that a good season sees them 

 so accompanied ; if not, they do not remain long. In 

 the typical cases, where the ring is annually provided 

 with its fringe of fungi, it may go on increasing in size for 

 years : records exist of rings which have been known to 

 go on flourishing for forty or sixty years, and large rings 

 on a hill-side could be seen from a considerable distance. 



As to their sizes, they are known to commence as very 

 small patches, but specimens have been measured as 

 much as 60 feet and more in diameter. Indeed one 

 observer refers to a fairy-ring which was nearly 100 feet 

 across. While regarding these cases as rare extremes, it 

 is well known that rings 12-20 feet in diameter have often 

 been recorded, and, as we shall see, these must be several 

 or many years old. 



Although fairy-rings are usually noticed in meadows 

 and on pasture lands, they are found on hills as well as 

 in valleys, on dry soil as well as on wet, in woods and on 

 heaths, and even in rocky places and situations near the 

 sea. Perhaps the only generalization possible in this 

 connexion is that they do not occur on highly-cultivated 

 rich land. 



On regarding carefully a typical fairy-ring, it may be 

 found to present the following characters : — The central 

 area, encompassed by the dark-green ring, consists of 

 poor or even withered herbage — it may be of inferior 

 grasses alone, or of these mixed with other plants. Then 

 comes the band of luxuriant grass forming the ring 

 proper; the grass composing this may be of more than 

 one kind — e.g. Lolium perenne (the perennial rye-grass), 

 Dactylis glomerata (the cock's-foot grass), and Broiiius 

 mollis (the soft brome) are common, . 



These grasses are rank, tall, and of a distinctly darker, 

 bluer green hue than the rest ; it is their coarseness,: 

 height, and especially the deeper colour, which render 

 them so prominent. Fringing this ring, at the proper 

 season, are found the spore-bearing heads of the Agarics^ 

 i.e. the mushrooms or toadstools as the case may be; 

 and if the observer digs carefully below the soil, he will- 

 find that these Agarics spring from a felted mass of root- 

 like threads, the mycelium of the fungus. Then, outside 

 all, comes the general herbage of the pasture, or whatever 

 it may be : this is often scanty, indicating poor soil, and 

 in any case is less luxuriant and lighter in colour than 

 the rank herbage of the ring itself. 



As with the herbage composing the rings, so the 

 Agarics fringing them may be of different kinds. In the 

 autumn the fairy-rings of this country and on the Con- 

 tinent commonly contain Marasmius oreades, Fr., a small 

 pale mushroom with cream-coloured gills, and much 

 esteemed as an esculent. It has a somewhat stroiig 

 aroinatic odour, and its myceliuin is attached to the 

 roots of the grasses among which it grows. It must not 

 be confounded with certain acrid species allied to it. 



The common mushroom {Agaricus campestris, L.) is 

 also frequently found in large circles, fringing more or 

 less complete fairy-rings. Among other forms may be 

 mentioned the gray Agaricus terreus, Schoeff, not uncom- 

 mon in beech- and fir- woods ; the " parasol mushroom " 

 {Agaricus procerus, Scop.), also not uncommon in fir- 

 woods and pastures, and spoken of as one of the 

 best of the esculent forms ; also Agaricus personatus, 

 Fr., with a lilac or purple stem. This is a late form, 



