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HARDWICKE'S SCIENCE-GOSSIP. 



We regret to record the death of Dr. J. Mann, 

 formerly a contributor to this journal, and well 

 known as a meteorologist and writer on astronomy. 

 Dr. Mann died at the age of 69. 



The British Association begins its meeting at 

 Birmingham on the 1st of September, under the 

 presidency of Sir Wm. Dawson, principal of McGill 

 College, Montreal. 



M. Chevreul, the distinguished French physicist 

 and authority on colour, attained his hundredth year 

 on Monday, August 16th. 



We much regret to have to record the death of a 

 young and promising naturalist and geologist, Mr. 

 Gerrard Kinahan, son of Mr. G. II. Kinahan, of the 

 Irish Geological Survey. Mr. Gerrard Kinahan died 

 from a wound with a poisoned arrow in a fight with 

 the African native tribes at Anyappa, whilst engaged 

 in exploration. 



The Grosvenor Museum for Chester and North 

 Wales was opened on August 12th by the Duke of 

 Westminister. 



MICROSCOPY. 



' Wilks' Cells, &c. — I should feel much obliged if 

 either you or one of your correspondents would tell 

 me how to use the " Wilks' Cell." I procured some 

 a few months since, as they seemed from all accounts 

 exactly to meet a want which I (and I should think 

 many) have long felt. I should be very glad too to 

 be told where I could find an account of the anatomy 

 of Dyticus marginalis. I have sometimes ventured 

 to think that it would add to the interest and value 

 of your widely-read magazine if you could be induced 

 to give us some "Studies of Common Animals" 

 which would help the physiological student in 

 the dissection of insects and small animals, in the 

 same way that the excellent " Studies of Common 

 Plants " help the botanical student.— R. S. R. 



Dendritic Spots on Paper. — With regard to 

 the dendritic spots on note-paper mentioned by H. 

 Muller in your July issue, in the "Journal of the 

 Chemical Society " for 1872, Professor Liversidge 

 describes some experiments he made with them, 

 and also their origin. He says the ash yielded by 

 the spots when tested with the blowpipe tinges the 

 flame with green. If they are moistened with 

 hydrochloric acid, they produce the blue due to 

 cupric chloride. With the borax lead, the reactions 

 are also those of copper, viz., green when hot, and 

 blue when cooled. If several spots are treated with 

 a strong ammonia solution, the liquid becomes blue. 

 Thus we see that they contain copper. Also it seems 



to be in combination with sulphur, for if a spot be 

 placed on a bright surface of silver, and moistened 

 with hydrochloric acid, a dark stain is produced. 

 The spots are soluble in a solution of ammonia, 'giving 

 it a blue tinge. Most paper contains sulphuric acid 

 in combination ; thus the sulphur in the spots cannot 

 b made cut by dissolving them in nitric acid, and 

 then testing for sulphuric acid. The markings 

 usually pass through the paper, and are then de- 

 veloped on both sides, though very seldom equally. 

 In the centre of the marking one may usually devise 

 a nucleus, which, when rolled with a hard smooth 

 body, becomes more or less burnished. Thus we see 

 that the spot is not a vegetable structure. The 

 particle of metal in the middle seems to have been 

 detached from the paper-making or finishing 

 machinery, and having combined with sulphur in the 

 paper, and perhaps with oxygen also ; and being 

 subjected to clamp, the metal is held in solution, and 

 when it dries the metal crystalises out. They are 

 generally supposed to be black oxide of manganese, 

 but they evidently are not. — Werindes. 



Studies in Microscopical Science. — We are 

 glad to welcome the first four parts of vol. 4 of this 

 important and excellent work. They deal as follows 

 — " Studies in Vegetable Physiology" (as illustrated 

 by the Vegetable Cell), "The Mammalian Testis," 

 " Normal Kidney," and " The Sea-fans." The 

 work is continued on exactly the same lines as here- 

 tofore, and the coloured illustrations are equal to any 

 of their predecessors in careful drawing and artistic 

 finish. The slides accompanying each part are in 

 Mr. Cole's best style of mounting. 



BOTANY. 



Dianthus Armeria and Prolifer. — I have 

 been led by Mr. Arnold's remarks (p. 45) as to the 

 scarcity of D. armeria in the previous two seasons, to 

 look for it this year. It occurs on several gravelly 

 banks not far from my house, which is about three 

 miles from Racton, the place quoted by him, and I find 

 it about as plentiful as heretofore. Perhaps the season 

 may affect its appearance in different years. Last year 

 I found in Hayling Island a little patch of D. prolifer 

 of remarkably vigorous habit, being a foot or upwards 

 in height ; and this summer, on searching further, I 

 have detected it in several other parts of the common 

 (South Hayling), but much more dwarf, perhaps an 

 average height of six inches. This plant is, I believe, 

 much more local than the former. — William Jffiry. 



The London Catalogue.— Mr. John Hanson 

 has raised a most interesting and important question 

 as to the London Catalogue. It seems to be neither 

 more nor less than this : Is this publication to be 



