when it comes from the extremely cold interstellar space and approaches the Sun, is seen to be full of inner life. Its most brilliant part, the nucleus, often changes its aspect. Sometimes it expands beyond measure, and dissolves into a nebulosity; or else it takes all sorts of strange aspects. Sometimes the comet appears so suddenly in the sky that one is induced to believe that it has suddenly become incandescent like a variable star. Sometimes it protrudes immense tails, attaining in some cases the length of 25, 50, 100, or even 160 million miles, and such tails grow in a few days, or even in a few hours, subdivide, and sweep through space at an incredible speed, always remaining turned away from the Sun, while the comet describes a sharp curve. Streams of incandescent matter have been seen to be emitted by some comets, and many of them show changes of luminosity unattended by corresponding changes of structure. Even traces of rotation have been noticed in a comet, while the comet Coggia of 1874 and 1881 seemed to drive before it waves of compressed and glowing matter, similar to the waves of air which we see in instantaneous photographs of bullets flying through the air.

So far as spectral analysis goes, we know that incandescent, or at least, glowing gases of carbon compounds (perhaps acetylene and carbon oxid), as well as vapours of iron and sodium-all in that extremely rarefied state which we see in Geissler's tubes-enter into the composition of comets; and we know, on the other hand, that the heads of the comets contain swarms of solid meteorites and cosmical dust. Besides, it is certain that as a comet approaches the Sun, considerable inner changes are going on in it. Its matter becomes luminous, and incandescent gases appear round its head, or maybe in the head itself. The difficulty of explaining all these changes is certainly immense. But there are at least three hypotheses-which, by the way, do not contradict each other-by means of which the various luminous effects which we see in the comets have been explained; and all these support the idea that the matter of a comet must be scattered more and more in space each time it passes near the sun. The collision of the meteorites within the comet and the consequent rise of temperature and evaporation have been advocated by Tait, and afterwards by Sir William Thomson (Lord Kelvin) before the British Association in 1870. Then, Olbers, Bessel, Zöllner, Roche, especially the Russian professor Bredikhin, and Lewis Boss in this country, have advocated the theory of electric repulsions taking place in the body of the comet under the influence of the electro-magnetic force of the Sun; and the exhaustive mathematical treatment of this subject by Bredikhin has convinced most astronomers of the necessity of taking these inner repulsive forces into account.19 And finally, there is the theory of Rydberg which he has

19 Bulletin de la Société des Naturalistes de Moscon, for several consecutive years. See Nature for the bibliography of these articles.

summed up in one sentence.

The comets,' he says, 'are the meteors of the interplanetary medium.' In other words, the sun, he maintains, is surrounded by a sort of outer atmosphere composed of extremely rarefied gases and extending far beyond the limits of its corona; and when a stony mass or a cloud of cosmical dust penetrates into that medium, it drives it, compresses it, and becomes inflamed in the very same way as a meteorite becomes incandescent when it enters the extremely rarefied gases surrounding our atmosphere at a height of a hundred miles or more above the Earth's surface.20 It is thus evident that whichever of these three hypotheses be accepted to interpret the observed facts, the disaggregation of the comets which pass periodically near the sun necessarily follows. Their constitutive matter is bound to be scattered in interplanetary space, either in the shape of vapours or in the shape of clusters of meteorites wandering along elliptic cometary orbits.

Such being the present state of our knowledge about comets and meteorites, it can be said in full confidence that the chances of our planet colliding with the head of a comet are extremely, if not infinitely, small; and that if such a collision took place, its effects upon the life of our globe would be hardly noticed at all. The thing which we know best about comets is their weight, and the total weight of a comet-grand though its luminous display may appear in the sky is quite insignificant. The assertion of the astronomer who maintained that a whole comet could be carried in a sack upon the shoulders was not meant as a joke. As to the shooting stars and the aëroliths which enter our atmosphere, their speed is so much reduced by our aërial envelope that we see aëroliths which have entered our atmosphere with a velocity of twenty to fifty miles per second moving at the end of their course through the air at the sluggish speed of only a few yards per second. The heaviest authenticated aërolith that has fallen upon the Earth in historical times weighed only 18 tons. This does not mean, of course, that there are not much heavier bodies moving in space without our knowing anything about them, and there is no reason whatever why such bodies should not occasionally meet the Earth in their wanderings; but what we can maintain is, that if they entered our atmosphere all the chances would be in favour of their being exploded by their own over-heated gases, in which case they would reach the surface of the Earth in the shape of small fragments. Our aërial surroundings, and the extremely rarefied gases which undoubtedly spread far beyond what may be properly described as the Earth's atmosphere, are a far better protection of the Earth than might

20 J. R. Rydberg, Grundzüge einer Kometen-Theorie. I could not find this work by applying to German publishers, and am bound to utilise only an excellent analysis of it, by Dr. Berberich, in Naturwissenschaftliche Rundschau, 1899, vol. xiv. pp. 365, 377. 3 s

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have been imagined at first sight. As to the small meteorites, they certainly reach the Earth in formidable numbers; it has been calculated that every year no fewer than 146,000 millions of them enter our atmosphere, where they continue to float in the shape of vapours or microscopical dust. But if all that dust were evenly distributed over the whole surface of the globe, it would take a hundred thousand years to raise that surface by one single inch.

In the slow process of evolution of celestial bodies the matter which is spread in space in the shape of solid dust and vapours plays undoubtedly, in the long run, a considerable part; and it will be one of the greatest services rendered to mankind by modern science, both for the increase of actual knowledge and for the general comprehension of the life of the universe, and consequently the unity of nature, to have brought into evidence this formerly unnoticed and unsuspected world of tiny mites of the celestial space, the meteorites. In how far the great displays of shooting stars have already contributed to widen our conceptions of the great Cosmos has been faintly indicated in the preceding pages. But these showers have also suggested to several astronomers the idea of a new and very probable hypothesis of origin of stars and planets out of that cosmical dust. This hypothesis, which has been worked out in detail by Sir Norman Lockyer, slowly grows in the minds of the students of Nature. But it is too important to be treated incidentally, and must make the subject of a subsequent separate study.

P. KROPOTKIN.

CROMWELL AND THE ELECTORATE

It is one of the curiosities of history that Cromwell, the traditional opponent of tyranny, was led to act, on obtaining power, more autocratically than Charles the First, and even to supply the direct precedent for what has hitherto been deemed an arbitrary exercise of power on the part of Charles the Second. Hallam, discussing the forfeiture, by the latter, of the borough charters, styled it 'the most dangerous aggression on public liberty that occurred in the present reign,' and asserted that no precedent could be found for the forfeiture of corporate privileges.' We shall find that his indictment applies strictly to the action of Cromwell himself, whose objects, and whose means of attaining them, were precisely those of his successor. It was as absolutely true of him as it was of Charles the Second, that, in Hallam's words, 'there was little prospect of obtaining a Parliament that would co-operate with the Stuart scheme of government: the same method of altering the electorate, by obtaining voluntary surrenders' of borough charters, was employed, and the same end was attained when the boroughs

received, instead, new charters, framing the constitution of the municipalities in a more oligarchical model, and reserving to the Crown the first appointment of those who were to form the governing part of the Corporation.2

This was the precedent set, I shall show, by Cromwell's government, to which, therefore, we may apply the conclusion expressed by Hallam :

There can be nothing so destructive to the English Constitution, not even the introduction of a military force, as the exclusion of the electoral body from their franchises.3

The example by which I shall make good the statements I have here advanced is that of the borough of Colchester. The proceedings of Cromwell's Committee for Corporations' supply the names of other boroughs, but Colchester affords a valuable type, being, as it was in the Civil War, a Puritan borough in a Puritan county devoted to the Eastern Association. Moreover, the access I have 1 Constitutional History.

2 Ibid.

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3 Ibid.

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enjoyed to its jealously guarded records has enabled me to combine the evidence of its Assembly Books with that of the State Papers preserved at the Public Record Office. Writing to me lately, and urging me to make this evidence public, Mr. Gardiner spoke of the great importance of the Colchester municipal election' as a test case in a government proceeding which appears to me far more worth consideration than the decimation' of the Royalists by Cromwell's major-generals.

It is important to bear in mind that at Colchester, and in other towns where the same system prevailed, changes of opinion in the elective body were not of necessity reflected in the governing Corporation. The members of that body were not subject to periodical re-election, and thus could only lose office by death, resignation, or gross misdemeanour. The senior members of the body, therefore, represented the electorate of a former period, and it was only very gradually, as new blood' was introduced from below, that the composition and political attitude of the whole body could be modified.

This was especially the case with the aldermen, who could only be chosen from among the assistants,' while these in turn, when a vacancy occurred, had to be taken from the common council. On the other hand the mayor, who, of course, was annually elected anew, had to be selected by the aldermen from two of their body nominated by the free-burgesses at large. Here, then, the popular voice made itself directly felt; and by closely watching the politics of the mayors successively chosen we obtain trustworthy evidence on the trend of popular feeling.

The position, in fact, had some analogy with the political system now prevailing in the United States, under which the nominally representative bodies may remain for a time unaffected by changes in the views of the electorate, even when these changes have found expression at the poll. In 1628 the corporate body at Colchester were still on the side of the Crown, while the free-burgesses were already voting for parliamentary candidates who belonged to the opposition. The latter's claim to return the members for the borough was then admitted by the House of Commons, and was not disputed till under the Commonwealth, when the Puritans had gained the upper hand in the corporate body, while the free-burgesses, conversely, had been driven into opposition to the government by Cromwell's autocratic rule. It was then the Cromwellians' turn to protest against popular election.

From 1642 to 1647 the cause of the Parliament, it seems clear, reigned supreme in Colchester. But nowhere, perhaps, was the reaction at the close of the Civil War more remarkable than in Essex. It was Essex-Essex, the first born of the Parliament '-which, as the army drew nearer London, petitioned, to Cromwell's disgust, that the country might not be eaten up, enslaved, and destroyed by an

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