June I, 1876] 



NATURE 



113 



knowledge of the flow of time. This he can, with slight 

 additional trouble, communicate to the external world, 

 although wanting the means of promulgation to any 

 great extent. Telegraphs, on the other hand, exactly 

 supply this want, and can spread abroad in all directions 

 the astronomer's information. Before the transfer of the 

 telegraphs to the State, the successful working of the 

 Greenwich system was due entirely to the existence of 

 amicable arrangements entered into by both parties. But 

 now that the time-signal system is, as it were, consoHdated, 

 it might well receive greater development. The principal 

 clocks, and those of pubHc institution"!, in our large cities 

 and towns, London included, should be more directly re- 

 gulated than is at present the case by the automatic signals 

 which can be so readily supplied by telegraph, and which 

 might usually be received (as at Westminster) in the clock 

 tower or chamber, for direct comparison with each par- 

 ticular clock. In large towns one wire could be made to 

 serve for many buildings, and the cost for each thus greatly 

 reduced. 



The efficient regulation of public clocks in the way 

 mentioned is however a thing entirely for the considera- 

 tion of the municipal bodies in the various cities and towns 

 concerned. But it is otherwise with the question of the 

 establishment of signals on our coasts for the giving of 

 Greenwich time to outward-bound or passing vessels. 

 This is a matter not merely of local, but of national 

 interest ; and, since the whole subject of the safety of our 

 ships at sea is now under the consideration of the 

 Imperial Legislature, it seems a proper time to direct 

 attention to the usefulness of such coast-signals, as 

 tending directly to the improvement of navigation, and 

 thereby contributing in an important degree to the further 

 protection of shipping. 



MIGRATION AND HABITS OF THE NOR- 

 WEGIAN LEMMING 



WITH all our recent knowledge of the Northern 

 Fauna, and the ample opportunities of the Scan- 

 dinavian naturalists, the animal in question still seems to 

 have evaded a thorough scrutiny and complete solution of 

 the why and wherefore of its remarkable migrations. Ten 

 consecutive summers spent in Norway have led Mr. W. 

 Duppa Crotch,^ in studying the creature, to propound a 

 novel view as to the impetus of its recurrent irruptions. 

 Passing by the traditional lore respecting its sudden 

 appearance in myriads, he discountenances the later 

 informed writers' explanation of hunger, or of the ap- 

 proach of severe weather, being the cause. Even " sur- 

 vival of the fittest," with its cogent subsidiary clauses, 

 according to our author, fails to serve as a substantial 

 reason, for, as he observes, none of the travellers sur- 

 vive. His own theory is a very simple one. The 

 bands of migrants always head westward, and at last, 

 in diminished numbers, perish in the sea. In one well 

 authenticated instance (Collet), a ship sailed for fifteen 

 minutes through a swarm, the wa'er being literally alive 

 with them far as the eye could reach. This migratory 

 instinct, Mr. Crotch assumes, is hereditary, their pro- 

 genitors in the good old times of geological age having 

 sojourned in a land of plenty, now submerged beneath 

 the Atlantic. According to him the migration is not all 

 completed in one year, as formerly supposed, nor do they, 

 as stated, form processions and cut their way through 

 obstacles ; but breeding several times in the season, 

 they gather in batches, and at intervals make a move west- 

 ward. Their pugnacity, he states, is astonishing, and the 

 a pproach of any animal, or even the shadow ot a cloud, 

 arouses theangerof this small creature hkeaguinea-pig,and 

 they back against a stone or rock uttering shrill defiance. 

 Our author found, in most examples, a bare patch on the 

 rump, due to their rubbing against the said buttress of 



' In a paper read before the Linnean Society, May 4. 



support when at bay. He wonders why a bare patch, and 

 not a callosity, should not result from this innate, appa- 

 rently hereditary habit. They cross wide lakes by swim- 

 ming, but when in the water they are easily frightened, 

 and lose all idea of direction, and are inevitably drowned 

 by a slight ruffling of the surface. It seems the reindeer 

 trample them under foot whenever the chance may occur, 

 and other enemies in the shape of hovering rapacious 

 birds and small carnivora thin the numbers considerably 

 as the Lemmings in force drive westward. The writer 

 also called attention to the fact that fossil remains 

 of the Lemming exist in England, as an evidence 

 that the animal had penetrated hither before this 

 island was severed from the continent. The subject 

 altogether is a most interesting and suggestive one, well 

 worthy of the investigation and observation of northern 

 sojourners. Even the recent views of Mr. Crotch, it 

 seems, does not set the whole question at rest There 

 possibly may be some physical or physiological reason 

 underneath ; at all events it is certainly remarkable how 

 a settled westward course is that chosen, calling to mind 

 the similar direction which races of men are assumed 

 to follow. 



THE SEYCHELLES ISLANDS ^ 



'T^HE Report mentioned below is dated 20th May, 1875, 

 -*- and refers to two visits made to the Islands of the 

 Seychelles group in 1 87 1 and 1874. The islands visited 

 by Mr. Home were Mahd, Praslin, Silhouette, La Diguej 

 F^licitd, Curieuse, Aux Frigates, St. Anne, and Aux 

 Cerfs. The soil, climate and products of the islands are 

 very similar, so that the remarks made are equally appli- 

 cable to all of them. The climate is healthy, although the 

 islands are situated almost under the equator, and the 

 Cascade Valley in Mah^ which is at an elevation of 1,500 

 feet above the sea, is pointed out as being especially 

 delightful. The seasons are two, the warm and wet, 

 during the north-west monsoon, from October to April : 

 and the comparatively cool and dry season from April to 

 October. The rainfall during the year is about 96 inches, 

 most of which falls during the wet season. 



Some of the islands have high mountain peaks, as 

 Mahd, with an elevation of 3,000 feet, and Silhouette with 

 an elevation of 2,500 feet ; the highest land in the other 

 islands is less than 1,500 feet. Lagoons often exist 

 between the base of the mountain and the flat sandy 

 beaches which exist in all the islands. In former times 

 crocodiles were abundant in the lagoons, but they have 

 now been extirpated. 



The islands are granitic with veins of trap. Coral reefs 

 are abundant but of small size, the largest being on the 

 north-east of Mahe, and the north-east and south-west of 

 Praslin. The surface of the islands is mountainous and 

 undulating. Granitic boulders are common, and are most 

 numerous near the mountain tops and in tne bottom of 

 ravines. The soil is rich and capable of producing any 

 kind of crop peculiar to the tropics. In many places, 

 however, the soil has been washed away, and some of the 

 islands are almost bare rock. There is much uncultivated 

 land, the greater proportion of which is good, but accord- 

 ing to Mr. Home, the people are either too lazy or too 

 poor to cultivate it. 



The chief produce of the islands is cocoa-nut oil and 

 fibre. The plantations of cocoa-nut palms are increasing, 

 and many of the young plants are now bearing, which 

 they do when ten or twelve years old. The value of a 

 plantation in full bearing is about three shillings per tree 

 per annum. The oil is extracted by the old primitive mill 

 which has been used in Ceylon and elsewhere for hundreds 

 of years. The fibre is extracted by machinery and will soon 



' Report on the Seychelles Islands. Addressed to the Honourable the 

 Colonial Secretary, by J. Home, Sub-Director Royal Botanical] Ga'deas, 

 Mauritius. 



