HARDWICKE'S SCIENCE-GOSSIP. 



277 



well in water. As much balsam as possible is re- 

 moved from the slides by scraping with a knife, and 

 then sulphuric acid is rubbed upon them with a glass 

 rod. They are then well washed. If necessary a 

 finishing touch may be given with a warm solution of 

 washing soda or methylated spirit and ammonia, to 

 remove all trace of grease. Sulphuric acid should be 

 ailded to water, or water to sulphuric acid very 

 gradually.— Thos. H. Powell. 



Opaque Glass Slides. — American microscopists 

 are using white porcelain glass slides for mounting 

 opaque objects, and black glass slides for white 

 objects. 



Axes of Double Refracting Substances, — 

 At a recent meeting of the Royal Microscopical So- 

 ciety, the President, H. C. Sorby, F.R.S., read a 

 paper on an improved method for distinguishing sub- 

 stances which consist of a wedge-shaped piece of 

 quartz, cut parallel to the positive axis of the crystal, 

 and made to slide into the eye-piece of the micro- 

 scope. When this passed across the field of view in 

 polarized light, every gradation of tint was succes- 

 sively produced by the varying thickness of the 

 quartz ; and by viewing ciystals through this it was 

 easy at once to determine the position of their axes, 

 by noting the effect upon the series of coloured bands 

 produced by the quartz scale. 



Diatoms. — We have received a capital little bro- 

 chure, published by the Industrial Publication Com- 

 pany, New York, entitled "Practical Directions for 

 Collecting, Preserving, Transporting, Preparing, and 

 Mounting Diatoms. " The articles are by Professor A. 

 Mead-Edwards, Professor C. Johnston, and Professor 

 Hamilton L. Smith— all well-known American mi- 

 croscopists. 



ZOOLOGY. 



Watford Natural History Society. — The 

 Rev. Dr. Gee recently read a lengthy and exhaustive 

 paper before this society on "Famous Trees in 

 Hertfordshire." Afterwards the members gave 

 their Hon. Secretary, Mr. J. J. Hopkinson, a hand- 

 some testimonial, as a tribute of their esteem, and 

 their appreciation of the energy he has displayed 

 since the society was founded a few years ago. Mr. 

 Hopkinson's labours in making the Watford Society 

 so successful shows what can be done by a man 

 who is in earnest. 



The Study of Practical Zoology. — Under 

 the name of "The Channel Islands Museum and 

 Institute of Pisciculture Society," a limited liability 

 company is being formed for the establishment, at 

 Jersey, of an Aquarium which shall also be a 

 "Zoological Station," similar to that founded by 

 Dr. A. Dohrn, at Naples, where yoimg zoologists can 

 study their science practically. Biological research 



will there be encouraged to the utmost, and lectures, 

 laboratories, apparatus, &c., will be provided for 

 students. A Museum, as well as a popular Aquarium,, 

 will be established in connection, in the Zoological 

 School, for the use of the public. The technical 

 control of this promising and much required institu- 

 tion will be undertaken by Mr. Saville Kent, F.L.S., 

 whose experience in marine aquaria, and wide repu- 

 tation as a marine zoologist, eminently fit him for the 

 post. 



Provincial Societies. — We have received a 

 copy of the "Transactions of the Cumberland 

 Association for the Advancement of Literature and 

 Science " — an organization which we should be glad 

 to see imitated in every part of Great Britain, as it 

 proves what can be done in the way of scientific 

 propagandism by co-operative effort. The volume 

 contains some capital papers by Dr. Dodgson, 

 J. F, Crosthwaite, R. F. Martin, R. Russell, 

 J. Clifton Ward, J. Richardson, W. Fletcher, 

 J. Birkett, J. D, Harington, &c., and is edited by 

 Mr. J. Clifton Ward, F.G.S., the President of the 

 Association. 



Colours of Birds' Eggs. — In an article on 

 this subject Von Reichenan concludes that birds 

 which build open nests uniformly have coloured egg?, ; 

 and that those which possess concealed or covered 

 nests have white eggs. He further states that in 

 open and ground nests the colour of the eggs has a 

 protective function. 



The Sense of Hearing. — Prof. Jager has 

 published an article on this subject, in which he 

 expresses his opinion that in animals possessing 

 nerve fibres, the organs of hearing are but a 

 specialisation of the general tactile sense. 



Spotted Crake. — On the i8th September I had 

 brought to me a beautiful male specimen of the 

 Spotted Crake {Crex porzatta). It had been killed 

 by a lad who mistook it for a rat, and threw a stone 

 at it as it ran along the side of a ditch. Though by 

 no means a rare bird in some districts, this is the 

 first instance that has come under my notice of its 

 capture in this part of Lancashire. — R. Staiulen, 

 Cossnargh. 



Remarkable Sagacity of a Lobster. — A few 

 days ago we had occasion to empty a tank containing 

 flat-fishes, and a flounder of eight inches in length 

 was inadvertently left buried in the shingle, where it 

 died. On refilling the tank, it was tenanted by three 

 lobsters {Homarus viarinus), one of which is an aged 

 veteran of unusual size, bearing an honourable array 

 of barnacles ; and he soon brought to light the hidden 

 flounder, with which he retired to a corner. In a 

 short time it was noticed that the flounder was 7ion 

 est. It was impossible the lobster could have eaten 

 it all in the interim, and the handle of a net revealed 

 the fact that, upon the approach of the two smaller 



