136 



SCIENCE-GOSSIP. 



sub-species, forms and varieties fully described. 

 The genera and man}- of the sub-genera are illustra- 

 ted by typical drawings which will greatly facilitate 

 the identification of species. A useful glossary of 

 terms used in the work precedes the monograph, 

 also a list of solutions used as chemical reactions ; 

 we think, however, that the glossary might be 

 usefully extended when Part II. is issued. Further, 

 though the work pretends only to be a descriptive 

 catalogue, it seems a great pity to lose so fine an 

 opportunity of fostering the popularity of lichen- 

 ology by adding a general introduction to its study. 

 With such guidance and this excellent " Catalogue" 

 the student would have little else to desire. At 

 present he must spend much time in hunting up 

 the most advanced views of the morphological 

 aspect of lichenology, which Mr. Crombie, with his 

 thorough knowledge of the subject, could concisely 

 set forth in comparatively few pages. Anything 

 which assists to save time in the early stages of 

 an abstruse study such as this, tends to the 

 multiplication of workers therein. No doubt in 

 the second part attention will be given to the 

 bibliography of the subject, or, at any rate, reference 

 be made to the titles of those works referred to for 

 first descriptions and nomenclature. With some 

 few additions, such as we have ventured to suggest, 

 this will prove to be quite in the front rank of 

 the many valuable ''Catalogues" already issued 

 by the Trustees of our National Museum. — [J-.T.C.] 



First Elements of Experimental Geometry, applied to 

 the Length, Area and Volume. By Paul Bert. 

 Translated from the French by Mrs. H. O. 

 Arnold-Foster. 2nd Ed., 123 pp. 8vo. fully illus- 

 trated. (London : Cassell & Company.) Price is. 6d. 



Some time ago we had occasion to notice (p. 40) 

 another work by M. Paul Bert. This, though 

 different in character, is equally original. It will 

 be useful for young or obtuse children as a first aid, 

 especially where there is a difficulty in remembering 

 geometrical problems. 



The Physical Geology and Geography of Great Britain : 

 A Manual of British Geology. By the late Sir 

 Andrew C. Ramsay, L.L.D., F.R.S., etc., Director- 

 General of the Geological Survey of the United 

 Kingdom, pp. xv and 421. 8vo, with a coloured 

 geological map and large number of illustrations. 

 Gth Ed. Edited by Horace B. Woodward, F.G.S. 

 (London : Edward Stanford, 1894.) Price ios. 6d. 



It is now sixteen 3 ears since the last edition of 

 this standard work was published, and it is needless 

 to remark upon the progress made during that 

 period in the science of geology, not only with 

 regard to these islands but generally. To persons 

 who take an intelligent interest in the features of 

 our country, this work will prove a lasting source 

 of pleasure. With the aid of the judiciously 

 chosen illustrations, one need not be a geologist 

 to grasp the meaning of the various rocky and 

 other formations, or to get some knowledge of the 

 fossil animals occurring in them. In editing 

 the sixth edition Mr. Horace Woodward has had 

 the assistance of Lad}* Ramsay, who has furnished 

 much material in the form of notes and corrections 

 of the last edition by her late husband. Sir 

 Archibald Geikie has revised that portion of the 

 book which refers to Scotland and its scenery. 

 Even the coloured map has undergone some re- 

 vision. The result is that this valuable manual 

 starts afresh on its useful course, thoroughly revised 

 and brought up to the standard of most recent 

 knowledge of the geology and cause of scenery in 

 Great Britain. 



il 



iMMfr 



MICROSCOPY 



Pond Life at Wislev. — In a small pool adjoin- 

 ing Boldremere and opposite the hotel, on July 7th, 

 members of the South London Entomological and 

 Natural History Society found Volvox globator 

 plentifully, also innumerable entomostraca, includ- 

 ing the lovely Diaptomus castor, with Cyclofs 

 qjtadricornis and species of Cypris, and several 

 scarlet water-mites. On weeds were the rotifers 

 Melicerta ringcns and Rotifer vulgaris, also the free- 

 swimming species with their tortoise-like carapaces. 

 — W. West, 75, Lewin Road, Streatham. 



Dendritic Crystals. — With regard to the 

 interesting remarks respecting dendritic crystals 

 in books (ante p. 85), may I add that it seems to 

 me that a lapse of many years is not necessary for 

 their formation. Two specimens have recently 

 come under my notice. One, an eighth of an inch 

 long, was found on a piece of government foolscap 

 paper, which probably had not been in existence 

 more than a couple of years. The other, three- 

 sixteenths of an inch long, was somewhat older, 

 having been found on a sheet of the copper-plate 

 bass music of " Israel in Egypt." This was 

 probably at least twenty years old.. — Eud. A. 

 Martin, Ravenswood, Thornton Heath; June igth, 

 1894. 



Dendritic Crystals in Books. — Mr. Tait's 

 interesting article (ante p. 85) on these curious little 

 objects, will have turned many hundred pairs of 

 eyes towards the pages of old books in search of 

 them, and an ample supply of facts relating to them 

 will soon be collected. The results of my own search 

 are as follows : They do not occur in any very 

 old books. I have examined a number of volumes 

 published in the seventeenth and eighteenth 

 centuries without finding any trace of them. In 

 a copy of " Gray's British Plants," printed in 1821, 

 they are abundant, but small and not very finely 

 branched, and mostly forming the centres of buff- 

 coloured spots similar to those found on paper 

 which is " loxed." In Cassell's "Illustrated History 

 of England," 185S, there are some, well developed, 

 but not very large. In Cassell's "Natural History," 

 four volumes, published without a date, the original 

 edition, there are some of a similar character, 

 mostly on the backs of the full-page tinted plates, 

 which are on a paper different from the rest of 

 the book. I have never observed them in actual 

 contact with the printer's ink. They occur on 

 the margins and other blank spaces, and generally 

 penetrate the paper so as to be just visible as 

 minute undefined spots on the other side. I have 

 found them most abundant on the blue-lined 

 paper of which account books are made. Such 

 books, made from fifteen to twenty years ago, 

 present full crops of them in the finest condition. 

 Books printed on good hard paper, whatever the 

 date, appear to be free from them. It is the softer 

 papers manufactured between 1S20 and 1880 on 

 which thej* are chiefly found. Probably some 

 paper manufacturer could explain the matter — 

 F. T. Mott, Leicester; July, 1894. 



