March, 1906.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



371 



movement, with a possibility of reclamation, by the 

 building- or raising of some kind of wall around areas 

 covered at high tide. Such appears to have been done, 

 for instance, around the mouth of the river Crouch. 



Apart from the steady planing down of the coast, 

 there is in East Anglia the additional danger of inunda- 

 tion. Some of the rich grazing grounds here are low- 

 iving marshes, protected only by low cliffs. 'i"he recent 

 fall of cliff at Pakefield, near Lowestoft, composed of 

 boulder-clay, is but another instance of the gradual 

 denudation of the cliffs, which, if not checked, must in 

 the long run threaten the broadlands with inundation 

 by the sea. There is every reason to think that before 

 such a catastrophe could take place the protection of 

 this portion of the coast would definitely be regarded as 

 a national duty, and this might prove a first step to- 

 wards the formation of a special Government depart- 

 ment, having as its raison d'etre coast protection in 

 general. 



In considering the disappearance of our cliffs we are 

 not just now concerned with the loss of land in the 

 pre-historic period, which was owing purely to a sub- 

 siding movement of the whole country. Of such a 

 widespread movement we have ample evidence in the 

 numerous submerged forests, of which traces are ob- 

 servable at abnormally low tides. That the subsidence 

 was of a gradual and tranquil nature is shown by the 

 very existence of such remains. The features of a land 

 surface are apt to become effaced immediately the play 

 of the waves commences to be felt upon it, and even 

 under the most favourable conditions many of the trees 

 would become w:ished out of the soil, whilst others 

 would be broken off short, so that their stumps alone 

 remained. But loss of land through subsidence of the 

 crust is a thing against which seaside authorities and 

 (iovernment departments might rage in vain. On the 

 other hand, similar loss by erosion or denudation can 

 be g uarded against, and this is what is now so eminently 

 desirable. 



The Isle of Sheppey has been from time immemorial 

 gradually slipping away into the sea, and the rich 

 har\est of semi-tropical fossil fruits, turtles, &.C., from 

 its London Clay clilfs iiave enriched many a museum. A 

 few mik's farther east, on the North Kent coast, we see 

 the wide stretch of flat meadow-land which extends in 

 a south-easterly direction towards Richborough, mark- 

 ing tlu silted-up bed of the water-way which formerly 

 di\ided the Isle of Thanet from the mainland. But 

 with the destruction of the tertiary cliffs at Reculver it 

 is probable that the sea would already have commenced 

 to reassert its right to the old channel were it not kept 

 back by arlilicial embankments. The Sister Towers, 

 which were, two centuries ago, at least a quarter of a 

 mile inland, now stand at the edge of a .sea wall, reared 

 by the Brethren of Trinity House. 



The Isle of Wight is, geologically considered, but an 

 outlier of the mainland, but the oulv historical refer- 

 ence to its lormer connection with 1-^ngland is contained 

 in that much-quoted passage in .Strabo, alleging that 

 carts laden with tin used to pass to the island at low 

 tide, in order to ship that much-prized commodity off 

 to I'ha'nician markets. If one takes one's stand upon 

 the l)i>wns near to Tennyson's monument, and looks 

 northward at low tide, one can easily conceive this to 

 have been the case, seeing that in addition to the spit 

 of land on which Iliust Castle is situated, numerous 

 banks show themselves above low-water mark, and 

 these are undoul)teilly the remains of a connecting link, 

 which must have Ikh'ii apjiarent not many centuries .'igo. 



The broken condition of the coast between Alum Bay 



and Colwell Bay give evidence of great falls of cliff 

 within modern times, and, indeed, geologically con- 

 sidered, there is no doubt that onlv a short time ago the 

 Solent was but a river which emptied itself into the 

 English Channel some distance beyond the Needles. 

 .\t this time the gradual erosion of Spithead, which was 

 going on, had not accomplished its work, and a bay 

 stretched out between Selsea Bill and Culver Cliff. It 

 is not a little remarkable in this connection that off 

 Selsea there is an anchorage which is even now known 

 as the Park. Probably the scour of the up-Channel 

 tides had a good deal to do with the erosion of the bay, 

 and even now the same action is responsible for a 

 phenomenon here, which is found only at one other 

 place on the south coast, namely, the movement of the 

 shingle from east to west instead of from west to east. 

 To the same cause may probably be attributed the 

 arrival in glacial times of the numerous boulders of 

 granite and other rocks foreign to the neighbourhood, 

 which have been seen at low water on the .Selsea coast. 

 That erosion of the opposite coast on the island is still 

 in progress is shown by the fall of tertiary cliffs which 

 are frequently reported from Brading and the neigh- 

 bouring east end of the island. 



Wherever the coast-line is made up of soft or 

 incoherent materials, from those parts comes the 

 strongest call for protection against the inroads of the 

 sea. On the iron-bound coasts of the west the batter- 

 ing-ram action of the sea has comparatively little effect. 

 The submergence of Lyonesse, and the development of 

 the hundred and fifty islands of which the Scillies con- 

 sist, cannot positively be attributed to erosion any more 

 than can the severing of St. Michael's Mount from the 

 mainland. Possibly in both of these cases, as also in 

 that of the development of the Bristol Channel, the pre- 

 sent contour has been brought about by actual sub- 

 sidence. 



But it is on the south and east coasts where land is 

 lost. The Oligocene and Eocene of the Isle of Wight; 

 the Thanet Sands of Peg well Bay; the Oldhaven Beds 

 and Woolwich Beds of the Heme Bay coast; the 

 London clay of Sheppey; the Red Crag (Pliocene) of 

 Suffolk; the boulder-clay of East Anglia and of the 

 Holderness district of Yorkshire; from all of these there 

 comes the news of constant denudation, imd it is in 

 respect to some of these that Government action will 

 have first to be taken, if the matter ever comes to be 

 regarded as one in which the State should interfere. 



New Radioactive Element. 



Mr. 0sk.\r K.min, in fractionating a mixture of bromides 

 obtained from thorianite, found that whilst the radium 

 accumulated in the least soluble fractions, the radio- 

 activity of the most soluble portions also increased. A 

 strongly active oxalate piecipitate of about 10 mg. was 

 finally obtained, which glowed faintly in the dark and 

 excited the platinocyanide and zinc sulphide screens in 

 a marked fashion. If a current of air is blown through 

 a solution of the substance and directed against a zinc 

 sulphide screen, the illumination of the latter is some- 

 what similar to that observed in a parallel experiment 

 with emanium. It is shown, however, that the 

 substance cannot be actinium or emanium. The 

 emanation from the substance is almost identical with 

 that of thorium, but the substance itstlf is fiom 

 100,000 to 200,000 times as active as thorium, and is 

 supposed to contain a new- radioactive element. 



