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HARDWICKE'S SCIENCE-GOSSIP. 



gayer than our familiar blue forget-me-nots, our 

 yellow iris, our scarlet poppies. But there is no need 

 to confine ourselves to British plants, and it is par- 

 ticularly instructive to grow exotics by the side of 

 their native allies. In my garden a plant of Paris 

 quadrifoHa from the Yorkshire dales is opening its 

 curious flower by the side of the lovely Trillium 

 grandijlorum — its Canadian cousin. The blooming 

 season appears identical. Similarly Primula farinosa 

 is growing by its beautiful Himalayan sister, Primula 

 rosea, and our wood anemone finds a congenial com- 

 parison with blue blossoms of ^. apcnnina. 



I do not of course suggest the substitution of a live 

 herbarium for a dead one, but that it is a most 

 desirable adjunct to it, more beautiful, more instruc- 

 tive, and far more enjoyable, is, I think, a fact not 

 nearly sufficiently recognised. Science is every day 

 bringing horticulture into closer union with botany. 



Wm. C. Hey. 



St. Olaves Vicarage, York. 



SCIENCE-GOSSIP. 



An important lecture has just been delivered 

 before the Royal Society of Dublin, by Dr. O. J. 

 Lodge, on "Dust-free Spaces," in which he gave a 

 summary of certain researches he has lately been 

 engaged in, which may ultimately prove of practical 

 importance. It is well known that we owe the blue 

 of the sky to the distribution of ultra-microscopical 

 dust particles— that is, to diffusion in the lower strata 

 of the atmosphere of foreign bodies. What we call 

 smoke is only the dust given off during combustion. 

 A cloud or mist is only so much water-dust. But a 

 fog is something more ; it is due to water vapour 

 having been condensed around each dust-particle as a 

 nucleus. Dr. Lodge and his colleague, Mr. Clark, 

 have found out how to disperse fogs. All our 

 readers know what they are in London, Manchester, 

 Liverpool, and elsewhere, and of late years they 

 have been increasing both in volume and density, 

 especially in the metropolis, until the phrase, "as 

 thick as a London fog," has become a proverb. 

 Evidently Dr. Lodge is not without hope that it can 

 be artificially dispersed, and moreover he means to 

 try. On a small scale he shows that the air can be 

 cleared of dust (and therefore of fog) by discharging 

 electricity into it ! Experiments made with turpen- 

 tine, smoke, vapour, magnesium ribbon, steam, and 

 artificially composed "London fog," carried out 

 before the audience, demonstrated that a charge of 

 electricity clarified the air containing them. Dr. 

 Lodge thinks it may be possible to clear the air of 

 our railway tunnels, by simply discharging electricity 

 into it, and that some impression may also be made 

 on a London fog by sufficiently powerful electrical 

 discharges. He referred to the old saying that 



" Thunder clears the air," in proof of the influence 

 which the electricity developed during a thunder- 

 storm has upon the previously murky atmosphere. 

 He intends to experiment in a genuine London fog 

 with large machines, and is of opinion that in this 

 respect the underground railway offers him a tempt- 

 ing field for experiment. 



A COPY has reached us of Mr. J. \V. Moll's paper 

 (in French) on the Potetometre, an apparatus devised 

 for the purpose of measuring the aspiration of water 

 by plants. 



The last number of the Proceedings of the Geo- 

 logists' Association, contains the following papers . 

 The President's address " On the Succession in the 

 Archaean Rocks of America, compared with that in 

 the Pre-Cambrian Rocks of Europe;" "On the 

 Methods which have been devised for the rapid 

 determination of the Specific Gravity of Minerals and 

 Rocks," by Professor Judd ; and "Description of 

 the Origin and Distribution of the Water-worn 

 Chalk-gravel of the Yorkshire Chalk Hills, &c." 



" The Naturalist's World '' is now per- 

 manently enlarged to twenty pages monthly, and 

 this month's number contains, among other interesting 

 matters, an article on " Cycling for Naturalists." 



Many years ago, a discussion took place in the 

 columns of SciENCE-GossiP as to who was the 

 author of the once famous " Vestiges of Creation," 

 and it was then conclusively shown to be the work 

 of the late Robert Chambers. In a new edition 

 of this work, Mr. Alexander Ireland, through whose 

 hands the MS. passed, publicly declares Robert 

 Chambers to have been the author. 



The Rev. C. W. Markham writes to say, that 

 whilst some labourers were excavating clay on some 

 level land in the Valley of Aucholme, near Brigg, in 

 Lincolnshire, they discovered, seven feet below the 

 surface, an ancient wooden way, composed of beams 

 of oak laid transversely. Six feet of solid clay lay 

 over it, and Mr. Markham thinks it is of neolithic age. 



We have received the last issues, respectively, of 

 the catalogues of scientific books issued by Mr. W. 

 Wesley, Essex Street, and Mr. W. P. Collins, 157 

 Great Portland Street. They include both new 

 and second-hand volumes, besides notable papers, 

 journals, &c. 



We have received the catalogue of scientific ap- 

 paratus and chemicals issued by Mr, Thomas Laurie, 

 31 Paternoster Row, valuable as showing what a 

 vast number of appliances are now placed at the 

 disposition of students. 



A NEW locality for emeralds has been found in 

 North CaroUna. The crystals are pale green, and 

 occur in decomposed black mica, associated with 

 quartz, rulile, <S:c. 



