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pounded, and with certain modifications adopted, by Proctor in the paper above named.

They assume with the customary matter-of-course confidence (which always astonishes me as coming from such unimaginative people) that the sun and all the planets of our solar system began life with a nebulous infancy, proceeded through a gaseous or vaporous childhood and liquid youth to a semi-solid puberty, when a film of solid crust crept over their liquid surface like whiskers on the cheeks of an adolescent.

It was, if I understand the theory rightly, at or about this period that the parturition of satellites occurred, according to Darwin and Ball; or somewhat earlier, according to Proctor. All agree in attributing the detachment of the satellite fragment or fragments to the tidal disturbances of the sun. They differ only as to the mode of operation of this agent. As the tide-raising power varies "not as the inverse square, but as the inverse cube" (see page 680), it is evident that the planets near to the sun must during their youth have suffered vastly greater tidal disturbance, or moon-generating agency, than the more distant, and therefore should have by far the largest families of satellites. Applying this test to the theory, it breaks down completely; for, instead of the satellites increasing in numbers with the proximity of the planets to the sun, the opposite is the case.

The two nearest planets, Mercury and Venus, have no satellites; the next, our earth, has one ; then, farther on, Mars has two; Jupiter, separated by a great gap, has four ; Saturn, still farther, has eight, besides the multitude of pebble-moons forming his rings. Thus far the facts are in direct and nearly quantitative contradiction to the theory. So far as we know, Uranus and Neptune have not the multitude of satellites required for establishing a law of increase with distance from the sun. I say, “so far as we know," because their distance is so great that if they had hundreds of such satellites as those of Mars we could not see them with any telescopic help at present available.

The effect of dimensions of the planet must of course be considered as well as that of distance from the sun in estimating the tide-raising efficiency of solar attraction ; but by comparing Jupiter and Saturn we have both of the tide-raising agencies so combined as to operate greatly in favour of Jupiter, and yet we find that his satellites are so much fewer.

Then, again, if we compare Venus and the earth, two planets differing in dimension by a mere fraction, we find that, instead of Venus indicating the results of a nearly threefold greater moon. generating action of the sun, it has not three moons, but no moon.

Man presents another contradiction to those subsequent proceedings of the satellites which the theory expounds. The solidity of Mars is that of a middle-aged planet, according to the theoretical description of planet-growth; but the position of its satellites so near to their primary is quite juvenile. The theory imperatively and mathematically demands that the distances of both Phobos and Deimos from their primary should be far greater than observation has proved them to be.

THE PHILOSOPHY OF MANURING.

A

READER writes for further information on this subject,

treated in a Note in the March number, to which I must now refer in order to save repetition.

First. Should the weed refuse be dug in fresh, or in the decom. posed condition produced by lying in a heap ?

From a strictly economical point of view it is desirable to dig in the fresh weeds, seeing that their decomposition in a manure heap must be attended with some loss of carbon, of ammonia, and of heat, all of which are so useful in the soil itself. But there may be an objection to this; for if the weeds have grown far enough to bear seed, or if they consist largely of plants with an underground stem (like couch grass, otherwise named “squitch"), their burial is followed by a troublesome resurrection. Therefore, some judgment is required in suiting the proceedings to the particular case. Generally speaking, the late autumn crop of weeds should be heaped and afterwards buried in the following spring, but the early young weeds buried on the spot at once, by simply hoeing them in.

Second. Should the refuse of a certain crop be the manure for the same kind of crop ?

This follows from the principle laid down of restoring what is removed from the soil. Of course, the whole cannot be restored thus when any is used, but in most cases the refuse far exceeds in bulk and manurial value the useful portion for which the crop is cultivated. This is strikingly the case in all kinds of sugar cultivation, pure sugar itself taking absolutely nothing from the soil, as explained in previous Notes.

Liebig tells the story of the poor vine-grower who could not afford to buy manure, and in despair carefully buried the trimmings of his vines close to their roots. He obtained thereby a good crop. In this case he returned a considerable proportion of the potash he had taken from the soil, this being the element which the vine so

largely removes, but of course the soil lost all that was taken away by the grapes.

One of my pedestrian trips in Italy was during the most disastrous prevalence of the oidium. The manner in which the grape failed in its growth before the fungus was visible on its skin, led me to suppose that the vines succumbed to the parasite from weakness due to exhaustion of the soil.

The general experience of vine-growers is very instructive. On one hand, we find records of partial and complete ruin from exhaustion due to neglect of manuring; and on the other, of mischief following as a direct consequence of ordinary manuring. This was the case with the celebrated Johannisberg vineyard while in the possession of General Killerman.

Thanks to the French Academy of Science, the prevailing error that attributed this to “over-manuring” has been dissipated. It was not the quantity but the quality that was in fault. To the unscientific farmer, dung and manure are synonymous terms; and if he has supplied the ground with customary muck, he supposes that he has done all.

This is sound for the grazier, who has to return what the animal takes away; but with such a crop as grapes, which removes so little ammonia and so much potash, the addition of nitrogenous manures is useless, and may even be poisonous. If all the trimmings of the vine and all the wine lees (grape skins and stones), plus as much potash as is contained in the precipitated argol (crude cream of tartar) and in the wine, are returned to the vineyard, its fertility will be uniform and perennial, provided its soluble material is not washed away by rains.

But there is an internal source of potash that must not be forgotten. Certain rock constituents, such as felspar, contain potash so combined that it can only dissolve out very slowly as the felspar decomposes. When the soil of a vineyard rests on a highly felspathic granite or similar rock, it may thus be fed from below with practically inexhaustible supplies, and its grape-producing fertility retained, even when the potash of the grape juice is carried quite away, provided this operation does not proceed more rapidly than the weathering of the rock restores it.

My theory of the appearance and prevalence of oidium for a few years in certain districts, followed by its apparently spontaneous disappearance, is that, in the first case, the potash supplies have been overtasked by abundant harvests; and in the second, they had been restored by the gradual decomposition of the felspathic material of

the soil or under-rock, during the compulsory fallow of the oidium period.

The above-named observations of the oidium were chiefly made on the Plains of Lombardy, the soil of which has been laid down by ancient glacier and torrent débris from the granitic Alps. It therefore contains vast stores of felspathic detritus that is very slowly giving up its potash in soluble form. Hence its fitness for the vine. But even this may be overtasked.

The above-stated principles apply to domestic gardening. If all the weeds and all the stalks of peas, beans, &c., waste leaves of cabbages, rhubarb, and similar refuse be returned, the ground only loses what is actually eaten. This may be fully restored by giving to the soil the domestic refuse otherwise carted away by the dusiman.

Fairy Rings.

You demi-puppets, that
By moonshine do the green sour ringlets make,
Whereof the ewe not bites.

CIENCE has been scarcely more explicit than Shakespeare con

,

although many attempts at explanation have been made. In spite of this, I have a theory of my own, which, halting though it be, I here expound.

I occupied during a few years a house on the slope of the Hope Mountain, near Caergwrle, in Flintshire. The house is named “Celyn" in the Ordnance maps. It commands a fine view of the Alyn valley and country beyond. The most conspicuous of the pasture fields displayed below had no fairy rings during the first and second years of my residence in the Celyn ; but on the third a large crop of them came into existence. They were arranged in orderly rows, and so conspicuous that they forced themselves continuously on my attention-were, in fact, almost irritating by their persistent appeals for explanation. They worried me thus every day from the September of one year to the July of the next, excepting when the snow was on the ground.

I walked down frequently to the field and examined the troublesome things, finding them always the same-viz., nearly true circles, and composed of coarser grass than that surrounding them, and at times with a crop of small fungi dotted over them. They varied very little in size, were about six feet in diameter—too small to have been the track of any tethered animal—but they evidently had received some kind of special manuring.

Suddenly, on one bright July morning, the mystery was solved. A crop of grass had been mowed, tossed, and winnowed, and was now in cocks ready for carrying to the stack. The circumference of the base of these cocks corresponded almost accurately with that of the fairy rings; their numbers and arrangements were nearly identical ; some of the cocks actually covered the area enclosed by the ringlets of the demi-puppets.

Then I remembered the history of the last year's harvest on that particular field. A weary continuance of drenching rain commenced just when the grass was cocked as now, and it remained thus on the ground for several weeks, until almost black with fungoid rotting. Here, then, was the explanation. The juices of the rotting grass had been washed down the slopes of the cocks, and with these juices were the fungus germs that “soured” the ground.

There would thus be effected a sort of special or differential manuring of circles, having outside diameters corresponding to that of the base of the cocks, and a thickness of ring equal to the depth of penetration and drainage of the rain.

The last year's history of this field was impressed on my memory by a small triumph of dilettante science applied to agriculture. My own grass was cut at the same time as the grass of this opposite field, and both were cocked on Friday in splendid weather ; but I had observed a steady fall of the barometer, and accordingly employed extra hands, and made a great bustle to get my hay carried on Saturday-worked till midnight—thereby amusing considerably my neighbours who were professional farmers. The fine weather continued through Saturday and on till Sunday night, when the rain began and continued, with the disastrous results above described.

I hope this Note may induce others to repeat my observation by looking for these fairy rings, and, when they find them, enquiring whether any kind of heap of vegetable matter formerly occupied the area included within their circuit.

THE COLOURS OF WATER.

ON

N the 6th of February last a paper was read at the Royal Society

by Mr. John Aitken which“ led to a considerable discussion among the Fellows."

The subject was the varying colours of water, which have been explained rather learnedly by selective reflection, selective absorption, and polarisation of light. Mr. Aitken's ex

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