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HARDWICKE'S SCIENCE-GOSSIP. 



I said I had found only one test which I could not 

 resolve, viz. Stauroneis spicula. I have lately suc- 

 ceeded in obtaining a very fair view of the lines by 

 using the greatest possible obliquity of light (sun- 

 light from the left), and bringing the valve just 

 within the field on the opposite side to the light. 

 My glass may not be equal to more (Siebert's 

 No. 7). The Illuminator professes simply to bring 

 out in a cheap and easy manner the actual powers 

 of the glass, be they what they may. Professor 

 H. S. Smith, of the United States, tells Mr. Kitton 

 he has long known of this plan of illumination, 

 having used a piece of looking-glass with a ledge. 

 He must have thought little of its utility, or kept 

 it to himself, for I do not know any one on this 

 side the Atlantic who has heard of it. I certainly 

 had not. — John Bramhall. 



ZOOLOGY. 



Notes from the British Association.— This 

 year's meeting will long be memorable for the com- 

 prehensive, philosophical, and eloquent addresses of 

 Mr. A. R. Wallace, and Professor Newton. The 

 former touched lightly but suggestively on all the 

 topics which have been raised since the publication 

 of the "Origin of Species," and we would strongly 

 advise all our readers who can, to peruse the address. 

 Professor Andrews, the President of the Associa- 

 tion, in his inaugural address, also dwelt upon 

 various zoological questions. Speaking on the 

 ravages of insects, he said they have ever been the 

 terror of the agriculturist, and the injury they 

 inflict is often incalculable. An enemy of this class 

 carried over from America, threatened lately with 

 ruin some of the finest vine districts in the south of 

 Prance. The occasion has called forth a chemist 

 of high renown ; and in a classical memoir recently 

 published, M. Dumas appears to have resolved the 

 difficult problem. His method, although imme- 

 diately applied to the Phylloxera of the vine, is a 

 general one, and will no doubt be found serviceable 

 in other cases. In the apterous state the Phylloxera 

 attacks the roots of the plant ; and the most effica- 

 cious method hitherto known of destroying it has 

 been to inundate the vineyard. After a long and 

 patient investigation, M. Dumas has discovered 

 that the sulphocarbonate of potassium, in dilute 

 solution, fulfils every condition required from an 

 insecticide, destroying the insect without injuring 

 the plant. The process requires time and patience ; 

 but the trials in the vineyard have fully confirmed 

 the experiments of the laboratory. We recommend 

 this specific to such of our readers who have been 

 asking various questions in our columns as to how 

 insecticide can be effectively carried on. Sir 

 Wyville Thomson's discourse on the results of 

 the Challenger expedition was listened to by 



upwards of two thousand people, but it is too 

 extensive for us to do more than allude to it here, 

 especially as we endeavoured to keep our readers 

 posted iu the most important discoveries made 

 during its progress. A good deal of Sir Wyville's 

 discourse turned on the physical geography of. the 

 sea, and the origin of currents. One of the most 

 powerful agents he evoked was the excess of pre- 

 cipitation over evaporation in the northern hemi- 

 sphere, and the contrary in the southern. Mr. 

 Murray, one of the naturalists on board the Chal- 

 lenger, read a long paper on " Ocean Deposits 

 and their Origin," in which he showed the kind of 

 work being done by lowly-organized animals in the 

 deep seas. Another important paper was that by 

 Mr. G. J. Romanes on the " Nervous System of 

 Medusa;," in which he showed from experiments 

 that along the margin of the disks of Medusae there 

 was situated an intensely localized system of centres 

 of spontaneity, or ganglia, to which the contractions 

 of the disk were due, so that he considered he had 

 finally settled the long-vexed question as to the 

 nervous system in these animals. He further 

 showed that there was no other instance in' the 

 animal kingdom of so great a disproportion between 

 the mass of central nerve-substance and that of the 

 system it was capable of animating, as there was 

 between the mass of the margin and that of the 

 bell of a large Medusa ; in one case this proportion 

 being only that of 1 to 30,000,000. This year's 

 meeting was noted for the presence of a great many 

 foreign naturalists of high repute ; such as Prof. 

 Hteckel, Prof. Cohn, Prof. Grube, and others. Prof. 

 Ha;ckel read a paper on the Lowest Porms of 

 Sponges, in which he stated that in all animals above 

 the rank of protozoa, there existed at an early stage 

 of development two distinct cell-layers ; one from 

 which all the organs of animal life were developed, 

 the other those of vegetating life. All animals 

 might then be divided into two classes,— those in 

 which there was no internal body-cavity— the Pro- 

 tozoa ; and those in which such a cavity existed— 

 the Metazoa. Prom these latter were developed, on 

 the one hand, echinodermata and ccelenterata, and 

 on the other vermes ; through which latter again 

 all the other groups of both invertebrates and ver- 

 tebrates were developed. The zoologists were 

 enabled, by the kindness of Mr. Duncan and Mr. 

 A. B. Stewart, to have several days' dredging in the 

 Kyles of Bute and the adjacent lochs. Of these 

 we say nothing now, except that they were days 

 long to be remembered for the spoils captured, as 

 we intend relating some of our experiences thereon 

 at length in an early number of Science-Gossip. 



Gold-fish Breeding.— Iu reply to many queries 

 respecting gold-fish breeding that have appeared in 

 Science-Gossip, it may be interesting to readers 

 to know that they can be successfully bred in an 



