BARBWICKE'S SCIENCE-GOSSIP. 



2 59 



its back and sides, and finally a sensitised gelatine 

 film placed over the polished face. The subject to 

 be etched is now photographed on the surface, and, 

 by washing, the soluble and unprinted parts of the 

 gelatine removed. A coating of asphalt is next 

 applied to the raised parts, the block ^steeped in 

 nitric acid of suitable strength (the stronger the 

 better), where it remains one hour, when it is re- 

 moved and subjected to the action of sulphuric acid 

 for the same time. The portions unprotected are 

 thus changed to nitro-cellulose, which, by brushing, 

 is readily removed in the form of a greenish powder. 

 To complete the process the block is dried and 

 briskly brushed with a stiff brush. The asphalt is 

 lastly removed with benzine, and the block is ready 

 for the press. The practical value as to depth and 

 retention of details we cannot state. It is an inno- 

 vation, however, that may prove worthy of attention. 



" One generation passeth away, and another 

 cometh ! " We are deeply sorry to have to record 

 the deaths of two personal friends, eminent geologists 

 and naturalists, and both of whom were deeply 

 attached to each other : the Rev. W. S. Symonds, 

 F.G.S., author of "Records of the Rocks," &c, and 

 Sir W. Guise, Bart., president of the Malvern Field 

 Club. 



A CAPITAL club, which combines social freedom 

 and relaxation with science, is the " Norwich Science- 

 Gossip Club," now numbering eighty members, after 

 being founded nearly twenty years, and meeting twice 

 a month during autumn and winter. We have just 

 received its "Report of Proceedings," with abstracts 

 of papers, President's Address, &c. All those who 

 meditate starting a " Scientific Free-and-Easy " 

 should write to the Hon. Sec. for details of manage- 

 ment and business. 



The new adventure, " The Naturalist's Monthly,'' 

 looks well, and has some attractive articles. The 

 demand for an enlarged periodical literature of 

 natural history proves how thoroughly these studies 

 are gaining ground among all classes. Our con- 

 temporary is ably edited by Dr. J. W. Williams (well 

 known to most of our readers), and is published by 

 W alter Scott, 24 Warwick Lane, Paternoster Row. 



A lecture was given a few days ago at the 

 American Exhibition, and was very largely attended 

 by mining men. Mr. F. W. Rudler, President of 

 the Geologists' Association, introduced the lecturer, 

 Professor A. E. Foote, of Philadelphia, who stated 

 that of the ninety-five millions of tons of coal pro- 

 duced yearly in the United States, nearly two-thirds 

 of the tonnage and fully two-thirds of the value were 

 from Pennsylvania. The utilisation of natural gas 

 had advanced so rapidly in the twelve years since its 

 introduction that it had supplanted the use of coal in 

 Pittsburg for nearly all purposes. The value of the 

 coal, the place of which it took, would this year 



probably amount to ,£6,000,000. The extinction of 

 the dividends on copper stocks was explained by the 

 enormous production of the Anaconda and other 

 Montana and Arizona mines, and the Calumet and 

 Hecla of Lake Superior. These supplies were prac- 

 tically inexhaustible. Other metals, useful non- 

 metallic minerals and gems, and ornamental stones 

 were referred to. The topaz found on the Amazon 

 Stone of Colorado, the emeralds, rubies, and sap- 

 phires of North Carolina, and the chlorastrolite and 

 zonochlorite of Lake Superior were among the most 

 novel and striking of American gems. 



MICROSCOPY. 



Enock's Slides. — A most interesting slide from 

 this celebrated mounter reached us last month too 

 late for notice, accompanied by the usual drawing and 

 sketch of entomological characters. It was the 

 parasite of the Hessian Fly — now as important an 

 object of study as the latter. It is a splendid object, 

 and so mounted that both sides of the insect can be 

 studied. 



"Journal of Microscopy." — (Edited by Alfred 

 Allen.) The October part of this well-known and 

 highly appreciated journal contains the following 

 papers, besides the usual copious notes, reports, 

 and views : — " Linaria Cymbalaria" by R. H. Moore ; 

 "The Photo-micography of Histological Subjects," 

 by Dr. Y. M.Young; "Puzzles in Paleontology," 

 by Miss Alice Bodington ; and "The Structure of 

 Flowers with reference to Insect aid in their Ferti- 

 lisation," by W. G. Wheatcroft. Most of the papers 

 are nicely illustrated by lithographs. 



Butterfly Dust. — In the "English Mechanic" 

 of September 30th is a remarkable article by Dr. 

 Royston Pigott, on "Butterfly Dust, Villi, and 

 Beads." The detection of villi in butterfly dust is a 

 new departure in microscopical work. Mr. Ernest 

 Hinton, of 12 Vorley Road, Upper Hollo way, has 

 brought out a capital preparation of the scales of a 

 moth {Zygcena_ irigoniliit) which illustrates the above 

 paper on villi in a remarkable manner. All micro- 

 scopists will be interested in the subject on account 

 of its high importance. 



Cuckoo's Mate.— The bird which arrives with 

 the cuckoo — noted by Henry C. Russell as the 

 "cuckoo's mate" — is the wry-neck, so named from 

 its peculiarity in clinging to the bough of a tree and 

 twisting its neck from side to side ; its cry is a shrill 

 quickly repeated whistle. It is, I should think, of 

 insectivorous habits. The origin of the expression 

 connecting the cuckoo with a cherry-tree is doubtless 

 only the alliteration of a nursery rhyme. — W. E. 

 Windus, Bex kill, Sussex. 



