church of the White Nuns of the order of St. Augustin, said to be found in the heart of a walnut-tree, on its being split with lightning. And it being usual in some countries to nail small images of our Saviour on the cross, of Virgin-Marys, &c. to trees by the road-side, in forests, and on commons; it would be no greater a miracle to find any of these buried in the wood of the tree, than it was to find the deer's horn so lodged.

Sir Hans Sloane, in his noble museum, has a log of wood brought by Mr. Cunningham from an island in the East.Indies, which, on being split, exhibited these words in Portuguese, DA BOA ORA. i. e. Det [Deus] bonam horam.

[Editor. Phil. Trans. 1739, Vol. XLI.

CHAPTER VIII.

FAIRY RINGS.

THIS curious phenomenon has been differently accounted for.

The following is Mr. Nicholson's description and explanation: "the appearance in the grass," says he, "commonly called Fairy Rings, is well known. It consists either of a ring of grass of more luxuriant ve. getation than the rest, or a kind of circular path in which the vege tation is more defective than elsewhere. It appears to be pretty well ascertained, that the latter state precedes the former. Two causes are assigned for this phenomenon: the one, which cannot be controverted, is the running of a fungus; the other, which has been considered as an effusion of theory, is grounded on a supposition that the explosion of lightning may produce effects of the same kind on the ground, as Dr. Priestley's battery was found to produce on the polished surface of a plate of metal, that is to say, a series of concentric rings. Some observations, which I find in my common. place book, appear to show that this last effect may, in certain cir cumstances, take place.

"On Tuesday the 19th of June, 1781, a very powerful thunder

storm passed over the western extremity of London. I was then at Battersea, and made no other remark on the phænomena than that the explosions, which were very marked and distinct, were in many instances forked at the lower end, but never at the top; whence it follows, that the clouds were in the positive state for the most part. On the following Sunday, namely the 24th, I happened to be n Kensington Gardens; in every part of which extensive piece of ground the lightning had left some marks of its agency, chiefly by discoloration of the grass in zigzag streaks, some of which were fifty or sixty yards in length. Instances of this superficial course of the lightning along the ground, before it enters the earth, are sufficiently frequent. But the circumstances which attracted my atten tion the most was seen in a small grove of trees at the angular point of one of the walks."

[Journal of Natural Philosophy, Vol. I. p. 546.

Dr. Darwin is well known to have been one of the chief advocates for this electrical hypothesis. It is thus he adverts to it in his Botanic Garden, Canto I. 1. 369:

So from dark clouds the playful lightning springs,

Rives the firm oak, or PRINTS THE FAIRY-RINGS.

Upon which he has the following note towards the end of the volume:

"There is a phenomenon, supposed to be electric, which is yet unaccounted for; I mean the Fairy-rings, as they are called, so often seen on the grass. The numerous flashes of lightning which occur every summer are, I believe, generally discharged upon the earth, and but seldom (if ever) from one cloud to another. Moist trees are the most frequent conductors of these flashes of lightning, and I am informed by purchasers of wood that innumerable trees are thus cracked and injured. At other times larger parts or prominences of clouds gradually sinking as they move along, are discharged on the moister parts of grassy plains. Now this knob or corner of a cloud, in being attracted by the earth will become nearly cylindrical, as loose wool would do when drawn out into a thread, and will strike the earth with a stream of electricity perhaps two or ten yards in diameter. Now, as a stream of electricity displaces the air it passes through, it is plain no part of the grass can be burnt

that where lightning falls so powerfully as to calcine turf, some effect will be perceptible on the substrata of soil, or gravel, &c. for even quartz, has been vitrified by lightning; but that no similar effect in any degree is to be discovered under fairy-rings, either recent or old, has been ascertained by accurate examination.

Instead of troubling you with any further observations of my own, - in refutation of the above theory, permit me to close with a quotation from the accurate botanical work of the late Dr. Withering; in which, after describing the agaricus orcades, the author explains the phenomenon of fairy-rings in a more satisfactory manner than has been done by any other writer.

"I am satisfied that the rare and brown, or highly-clothed and verdant circles, in pasture fields, called fairy-rings, are caused by the growth of this agaric. We have many of them in Edgbaston Park, on the side of a field sloping to the south-west, of various sizes; but the largest, which is eighteen feet in diameter, and about as many inches broad in the periphery, where the agarics grow, has existed for some years on the slope of an adjoining pasture-field, facing the south. The soil is there on a gravelly bottom. The larger circles are seldom complete. The large one just now described, is more than a semi-circle, but this phenomenon is not strictly limited to a circular figure. Where the ring is brown and almost bare, upon digging up the soil, to the depth of about two inches, the spawn of the fungus will be found of a greyish white colour; but where the grass has again grown green and rank, I never found any of the spawn existing. A similar mode of growth takes place in some of the crustaceous lichens, particularly in the L. centrifugus, which spreads from a center to the circumference, and gradually decays in the middle; an observation made by Linnéus, and which is equally applicable to the general tendency of growth in the agaricus orcades."

[Monthly Mag. vol. xv. Editor.