EE VIEWS. 



117 



vincc towards its confines. Out of the many hundreds of land-mollusks 

 inhabiting the Caucasian province at its specific centre, only ninety have 

 reached the British Isles ; of which thirty-five stop short of Scotland, and 

 nineteen in Ireland. Their progress northwards, it may be argued, is 

 arrested, to a great extent, by a change of climate, and in all directions by 

 foes, by mountain-barriers, by rivers, and by other physical and unknown 

 causes. It will readily be conceded that land-species have greater facilities 

 of locomotion than freshwater species especially inhabiting stagnant ponds 

 and ditches ; and it should follow, according to the doctrine of migration, 

 that the further off freshwater species are from the specific centre of a pro- 

 vince, the more diminished in number than land-species they would be. 

 The very contrary is the fact ; out of five hundred and sixty species of 

 Helix inhabiting the Caucasian province, a very large proportion of which 

 are assembled at its specific centre, we have but twenty-four in Britain, of 

 which only eleven range throughout. The disproportion in the number of 

 Clausilia is larger still. This genus is especially populous at its specific 

 centre. Between two and three hundred species inhabit Austria and 

 Hungary, yet we have but four in Britain, of which only one ranges 

 throughout. Let us now turn to the sluggish mud-dwelling Lymneeacea of 

 the ponds and ditches of the province. There are not six species, it may 

 be safely stated, in all Europe more than there are in Britain. They have 

 no particular centre of creation. There is no evidence to show whether 

 the alleged primogenitors of our British species were created in Siberia, 

 Hungary, or Thibet. There is scarcely any variation, either in the form 

 or number of the species in those remote localities." 



The other topics are equally well discussed, and valuable facts brought to 

 bear upon them ; and altogether, although the arguments are very concisely 

 stated, we have very valuable considerations very lucidly put. A complete 

 bibliographical list and an excellent index complete this useful volume, which 

 will doubtless, and deservedly, find a proper place in most naturalists' 

 libraries. 



Tear Boole of Facts, 1863. By John Timbs, F.S.A. 

 London : Lockwood and Co. 1863. 



Every year Mr. Timbs issues, and we receive, a ' Book of Facts.' These 

 are not, however, Mr. Timbs's facts, but the property of numerous people. 

 The book is, as is well known, a series of cuttings from various publica- 

 tions, l.ut not the less a useful book that it is composed of the "pickings" 

 of wise men's brains. If we cannot always depend on the judgment and 

 knowledge of the compiler, as displayed in his selections, or if we should 

 think him a little too much attached to certain publications, and a little 

 oblivious of or antagonistic towards others, he at least is not altogether un- 

 allocable, for he shows his partiality by naming and praising his Favourites, 

 and with respeel to the rest, merely uses their matter, and consigns to 

 oblivion their names and their fames. I n the present volume t he materials 

 are beyond the average value of Mr. Timbs's former year- books ; and he- 

 sides the section devoted specially to Geology, there are scattered articles 

 in various other portions interesting to geologists, such as the "origin of 

 petroleum," '•machine for cutting coal worked by compressed air," Ran- 

 BOme's artificial stone," coal '•and iron of South Yorkshire." "artesian 

 wells," " secular cooling of the earth," and " tin" relations between earth- 

 quakes and magnetic disturbances." 



