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HARDWICKE'S SCIENCE- GO S SIP. 



and from which no gathering is free. The acids 

 have no effect on them. Can any one suggest some 

 way either of removing the sand or of picking out 

 the diatoms from among it ? — St. T. E. 



A New Self-centring Turntable. — Mr. C. 

 F. Cox, of New York, has contrived a turntable 

 which is said to centre the slide unerringly, and is 

 at the same time a convenient working instrument. 

 The slide is held, by pressure upon two diagonally 

 opposite corners, between two clutches, that are 

 made, by a right and left screw, to move towards or 

 from the centre simultaneously, and at a uniform 

 rate. The centre of revolution must therefore 

 coincide with the centre of the diagonal of the slide, 

 which is the exact centre of a truly rectangular 

 slide, and is practically the centre of any slide fit to 

 be used. This very useful piece of apparatus is not 

 patented. Eor all new work, such as making var. 

 nish cells, or centring cells or objects of any kind, 

 this turntable is said to supersede all others. For 

 repairing old work, which may not have been well 

 centred originally, it should be provided with a 

 spring clip, under which a mounted object can be 

 centred by the concentric circles in the usual 

 manner, and which, when not in use, can be en- 

 tirely removed from the table. 



The Quekett Microscopical Club. — The last 

 number of the journal of this well-known and 

 practical society is now out. It contains papers, by 

 Messrs. W. W. Jones "On an Instrument for 

 Cleaning Thin Covering Glass"; on "Bucephalus 

 Haimeanus, and another allied Organism," by Dr. 

 Moore; on "The Relation of Bucephalus to the 

 Cockle," by W. Fell Woods; and on "The Organic 

 Structure of Flint and of Meerschaum," by M. H. 

 Johnson, F.G.S. In the latter paper, the author 

 states that meerschaum is a fossil sponge. The 

 organic structure of flint may easily be made visible 

 by staining thin chips with acetate of rosaline. 

 Among the number of nodular bodies which Mr. 

 Johnson claims to have made out as being of 

 a decidedly organic character, are meerschaum, the 

 Red Crag phosphatic nodules, septaria from the 

 London clay, chalk flints, green-coated nodules of 

 chalk rock, greensand phosphatic nodules, gault 

 phosphatic nodules, oolitic bodies, ironstone in coal- 

 measure sandstones, chert from mountain limestone, 

 iron pyrites in the chalk, and the phosphatic nodules 

 of the Lower Silurian strata of North Wales. 



ZOOLOGY. 



A Contribution to Darwinism.— Under this 

 heading Dr. T. Eimer has given an account of a pecu- 

 liar lizard, nearly allied to Laoertamuralis, found on 

 the uninhabited and rocky islets on the south-east 

 coast of the isle of Capri. M. Eimer obtained the 



lizards thence for the purpose of ascertaining 

 whether the conditions of isolation had not exercised 

 some influence on them. Such, he thinks, is de- 

 cidedly the case ; and the remarkable variety of 

 lizard he now describes under the name of ccerulea 

 is so distinct from the type, that in the eyes of many 

 zoologists it might be regarded as a species. L. 

 muralis is a native both of Germany and Italy, and 

 this new form of M. Eimer's differs less from the 

 Italian type than from the German. Not only is it 

 different in its colour, as well as in the shape of the 

 head, but likewise in its habits of life. From the 

 conjoined differences M. Eimer thinks that ccerulea 

 is entitled to rank as a species, although its affini- 

 ties and habits clearly show from what stock it has 

 sprung, and that it furnishes a striking example of 

 ■what has been called " an incipient species." 



The Colorado Beetle.— Much has been said 

 and written, both in England and America, in regard 

 to the habits of the "Colorado potato - beetle " 

 (Doryphora 10-lineata), and the probabilities of its 

 introduction into England and the continent of 

 Europe. It is an insect that no country need covet, 

 and therefore it is not surprising that foreign govern- 

 ments should be adoptiug measures to forestall it. 

 But from my observations during the past three or 

 four years, and especially within the last half-year, 

 I think the " non-importation of potatoes " from 

 this country will not reach the case. In the first 

 place, the females never deposit their eggs on the 

 tubers, and the larvae never feed on them. Early 

 in spring, before succulent vegetation has come for- 

 ward, and late in autumn, when such vegetation is 

 past, the mature beetles will prey upon the tuber ; 

 but this rarely occurs, except when the weather in 

 spring is prematurely warm, and then they will feed 

 on almost any kind of vegetation to which they have 

 access. The last broods of the season in autumn 

 go into the ground, change to a. pupa, and hybernate 

 there all winter. The theory in the Western States 

 is, that the perfect beetles also go into the ground 

 for hybernation, but we do not find this to be univer- 

 sally the case here in the Middle States. I saw 

 them last fall crawling under doorsteps, and through 

 cellar-grates, and other places of shelter, by scores, 

 here in the city of Lancaster; and I also saw them 

 come foith again, in the spring of the present year, 

 from like places. In the fields many of them were 

 found under heaps of rubbish during the winter. 

 No degree of cold had any effect upon them. Last 

 winter the soil was frozen down from 3 to 5 feet in 

 depth, and continued so all winter; and yet the 

 potato-beetles were dug up in February, only about 

 G inches from the surface, with the earth around 

 them as hard as a block of ice, and within half an 

 hour after they were removed to a warm room they 

 revived, and became as animated as they are in 

 summer. On a late visit to Cape Henlopen I found 



