HARDWICKE'S SCIENCE-GOSSIP. 



14: 



which these conditions have on fool's parsley, as on 

 hemlock, is to increase or diminish its succulency." — 

 F. IK E. S. 



Dytiscus marginalis. — For some time during 

 the past summer I kept the larva of one of these 

 creatures. It was exceedingly fierce, and would 

 fight a piece of stick or anything else that was put 

 into the glass it was kept in. On one occasion it 

 caught my finger and drew blood from it with its 

 powerful jaws. I fed it on raw meat which it worried 

 as a cat does a mouse. But it was troubled by a 

 hairy mould about \ inch in length. Could any of 

 your correspondents tell me what caused this ? — 



y. A. c. 



CONTR.\ST BETWEEN THE COLOURS OF FLOWERS 



AND Fruits. — Mr. Saunders seems to think that the 

 two classes of creatures, insects and birds, are at- 

 tracted to plants by two prevailing tints. One can 

 easily understand the advantage derived by plants 

 whose brightly-coloured flowers attract insects, be- 

 cause the visits of the latter ensure cross-fertilisation. 

 But I fail to perceive the benefit accruing when birds 

 are attracted by another kind of colour to consume 

 the fruits and seeds, for in that case I should have 

 imagined the chances of the plant being able to 

 perpetuate itself would be considerably diminished. 

 Does Mr. Saunders mean to infer that the seeds or fruits 

 which are most liable to destruction are subject to 

 the least competition among themselves, and there- 

 fore those which are not destroyed stand a better 

 chance of being perpetuated ? Or does he think the 

 seeds which are eaten are not necessarily digested, 

 but being cast out with the freces, are in a good 

 position to be sown and manured at the same time ? 

 An answer to the first question in the affirmative 

 might be correct to a great extent, but the suggestion 

 conveyed in the second question, I believe, has been 

 frequently tested by experiment (see chapter on Geo- 

 graphical Distribution, Mr. Darwin's "Origin of 

 Species) " and has held true only to a very limited 

 degree. My view of the contrast of colour displayed 

 between flowers and fruits would have been, that 

 whereas in the former it attracts insects (or birds), in 

 the latter it acts as a protection. Hence the variety 

 of brilliantly-coloured seeds compared with those of 

 a more sombre hue would, in my idea, render the 

 majority of them less conspicuous, and thus tend to 

 counteract the exterminating effects accompanying 

 the depredation of small birds. — yo/i/i Hanson, 



NOTICES TO CORRESPONDENTS. 



To Correspondents and Exchangers. — As we now 

 publish Science-Gossip earlier than heretofore, we cannot 

 possibly insert in the following number any communications 

 which reach us later than the 8th of the previous month. 



To Anonymous Querists. — We receive so many queries 

 which do not bear the writers' names that we are forced to 

 adhere to our rule of not noticing them. 



To Dealers and others. — We are always glad to treat 

 dealers in natural history objects on the same fair and general 

 ground as amateurs, in so far as the " exchanges " offered are fair 

 exchanges. But it is evident that, when their offers are simply 

 disguised advertisements, for the purpose of evading the cost of 

 advertising, an advantage is taken o( onr gratuitous insertion of 

 "exchanges" which cannot be tolerated. 



G. Wright. — Yes. Cassell's "Natural History" is much 

 better than the work you mention, which entails reading a text 

 that is frequently erroneous and nearly always unscientifically 

 arranged, and then the foot-notes, which usually contradict or 

 set the text right. Human life is too short for so roundabout 

 a way of acquiring knowledge. 



H. M. — See paragraph in our May number respecting the 

 occurrence of diatoms in the Coal Measures. 



B. Hook; wishes to know of a good means of whitening small 

 bones of birds, &c. 



Lepidopterous names.— In answer to J. P. the authors are 

 1-9 Linnffius, 10 Scopoli, n Ochsenheimer, 12 Ochsenheimer, 

 also Hiibner. 



J. O.— Most water contains a certain amount of lime, either 

 as the carbonate or the sulphate. Now it is well known that 

 water holding salt in solution freezes at a very much lower tem- 

 perature than pure water, as may be seen from sea water, which 

 contains sodium chloride. The water is boiled to get rid of the 

 carbonate of lime (boiling does not affect the sulphate), and so 

 freezes sooner than it would do if the lime were present. Boiled 

 water is often used by chemists for this reason, when distilled 

 water cannot be got. 



J. P. requests the authors of the names of some Lepidoptera. 

 The following list is to be found in Morris's " British Butter- 

 flies :" I Boisduval, Godart; 2 Linnaeus, Lewin, Donovan, 

 Harris; 3 Schrank, Latreille, Boisduval, Zetterstedt ; 4 Schrank, 

 Latreille, Boisduval, Stephens, Curtis, Duncan ; 5 Schrank, 

 Latreille, Boisduval, Zetterstedt; 6 Latreille, Boisduval, Du- 

 ponchel ; 7 Latreille, Boisduval, Duponchel ; 8 Godart, Hub- 

 ner, Latreille, Meyer ; 9 Fabricius, Stephens, Curtis, Duncan, 

 Westwood ; 10 Stephens, Curtis, Duncan, Westwood, Wood, 

 Latreille, Jermyn ; 11 Stephens, Curtis, Wood, Duncan, AVest- 

 wood; 12 Stephens, Wood, Duncan, Westwood, Jermvn. — 

 H. R. P. 



H. Lamb. — Your specimen is a white v.ariety of Goaninm 

 moUc. 



J. A. Wheldon.— Apply to No. 3 St. Martin's Lane, Trafalgar 

 Square, for regulations of Botanical Exchange Club. 



E. H. Smith. — Obtain one of the half-holiday handbooks 

 called "Geological Rambles round London," published at a 

 very cheap price by Marshall, Japp, & Co., London. It gives 

 you very clear instructions, how and where to go for metro- 

 politan geologising. 



H. A. Francis.— Accept our best thanks for the mounted 

 specimens of earth. Hcllehorns viridis is not an uncommon 

 plant in England, although sparsely distributed. 



W. W. Rust. — Hewitson's " Eggs of British Birds," in 2 vols. 

 published by Van Voorst, gives beautiful coloured, or rather 

 tinted illustrations of the eggs of every species of British bird. 



W. H. B. — We do not undertake to return rejected MSS. 



J. B. — The specimen you forwarded is not a grass but a sedge, 

 called CaTCX pulla (variety). For instructions as to mounting, 

 &c., read INIr. Britten's paper on "Collecting and Preserving 

 Natural History objects," published by D. Bogue, 3 St. Martin's 

 Place, Trafalgar Square, at 3^'. dd. 



Swiss Alpine Flora. — The most portable general Flora of 

 Switzerland is the " Flore Analytique de la Suisse," par P- 

 Morthier. It has 451 pages, and measures i\ in. by 3*}. The 

 publishers are Sandoz & Fischbacher, Paris ; Jules Sandoz, 

 Neuchatel. Mine is a copy of the second edition, 1872. I do 

 not know whether there is any Flora restricted to the Alps of 

 Switzerland except those of large size with illustrations of the 

 species. — J. Y. J. 



H. H. — In 1S77 there was a new section-cutter exhibited to 

 the Quekett ^iicroscopical Society by Mr. H. F. Hailes, 

 which obtained high praise for its simplicity and practical 

 utility. Perhaps some correspondent may be able to saj' where 

 this is to be obtained, and what is its cost. — y. V. J. 



EXCHANGES. 



Wanted, Newman's " British Moths," and Newman's 

 " British Butterflies." Offered, fossil micro slides in great 

 variety. — A, B. C, Post-office, Kilwinning. 



Wanted, all the hack numbers of " Grevillea," bound or un- 

 bound, except the first two volumes. — E. D. Marquand, Hea, 

 Madron, Penzance. 



Objects for marine aquaria, comprising some of our most 

 beautiful anemones, zoophytes, algae, etc. ; also several kinds of 

 the rarer British marine shells, and other objects in natural 

 history, land and marine. Wanted, scientific books, or instru- 

 ments.— J. Sinel, " Bagot," Jersey. 



Wanted, in fruit, species of Fissidens, all except bryoides ; 

 also species of Phascum. Exchange of fern plants. — Miss Ridley, 

 7 Cambridge Square, London, W. 



Wanted, fine chalk fossils for fine and perfectly-preserved 

 crystals of the following: Celestine, Dolomite, Smoky, Amethys- 

 tine, and other quartz ; and Fluor spores of all forms and colours 

 from Durham, Cumberland, Cornwall, Devonshire, the Hartz 

 Mountains, and elsewhere. — A. Butt, Vine Cottage, Perry Vale, 

 Forest Hill, London. 



Dr. Morse's "Zoology" (published by Kegan Paul), quite 

 clean, for microscopic apparatus or mounted objects. Stamp 

 for list of several other books. — M. B., 49 Mortimer Sreet, W. 



