widely distributed round its orbit, and the return in 1905 was very disappointing, the reason apparently being that the dense group in close attendance on the comet has suffered disturbance from Jupiter and Saturn, and now passes more than a million miles outside the earth's orbit. In 1843 there appeared one of the most remarkable of recorded comets. It was not only of conspicuous brilliancy and size, though its tail at one stage reached the enormous length of 200,000,000 miles, but was remarkable for the extraordinarily close approach which it made to the sun. Its centre came as near to the sun as 78,000 miles, leaving no more than 32,000 miles between the surfaces of the two bodies; it must, therefore, have passed clear through the corona, and very probably through some of the prominences. Its enormous tail was whirled, or rather appeared to be whirled, right round the sun in a little over two hours, thus affording conclusive proof that the tail of a comet cannot possibly be an appendage, but must consist of perpetually renewed emanations from the nucleus. But in addition to these wonders, the comet of 1843 proved the precursor of a series of fine comets travelling in orbits which were practically identical. The great southern comet of 1880 proved, when its orbit had been computed, to follow a path almost exactly the same as that of its predecessor of thirty-seven years before. It seemed inconceivable that a body so remarkable as the 1843 comet should have a period of only thirty-seven years, and yet never previously have attracted attention. Before the question had been fairly discussed, it was accentuated by the discovery, in 1881, of a comet whose orbit was almost indistinguishable from that of the comet of 1807. But the 1807 comet was not due to return till A.D. 3346. Further, the comet of 1881 proved to have a period, not of seventy-four years, as would have been the case had it been a return of that of 1807, but of 2,429 years. The only possible conclusion was that here were two comets which were really fragments of one great comet which had suffered disruption, as Biela's comet visibly did, and that one fragment followed in the other's wake with an interval of seventy-four years.