128 



KNOWLEDGE. 



April, 1915. 



the science to understand the papers in which the results of 

 investigations are described. 



The value of a book, therefore, which, while not over- 

 burdened with detail, yet gives a clear survey of the methods 

 of investigation and of the results so far achieved, cannot 

 easily be overrated ; and Dr. Rosenhain is to be congratu- 

 lated on having given us in the present volume just such 

 a book. The microscopic examination of metals, from the 

 selection and preparation of the specimen to the interpreta- 

 tion of the structures revealed, is discussed with the sure 

 touch of one with considerable experience, whilst the 

 lucidity with which the construction of constitutional 

 diagrams is described, and several typical alloy systems — 

 and notably the iron-carbon system — are discussed, 

 reveals the born teacher. The second half of the book 

 is devoted to " the properties of metals as related to 

 their structure and constitution." In this part are dis- 

 cussed the mechanical testing of metals, the effect of 

 strain, and the thermal and mechanical treatments of 

 metal. The final chapter deals with " Defects and Failures 

 in Metals and Alloys." The book is illustrated with numer- 

 ous excellent reproductions of photomicrographs, but the 

 omission of all details as to subject and magnification on 

 the plates themselves, and in most cases of the page number 

 of a given plate in the text, is a constant source of annoy- 

 ance to the reader, necessitating repeated references to the 

 list of plates at the beginning of the book. It is unfortunate 

 also that the chapter on " The Thermal Study of Metals 

 and Alloys " should be marred by several typographical 



errors. With these exceptions, however, we have nothing 

 but praise for a book which can be unreservedly recom- 

 mended to all who are beginning the study of physical 

 mi'tallnrgy, and to those who, as manufacturers or users, 

 are chiefly interested in the properties of metals from the 

 " practical " side 



T. S. 

 POND LIFE. 



/'"/.<</ Life. — By E. C. Ash. 92 pages. Numerous figures 

 in the text. 6 j-in. x 4£-in. 



(T. C. & E. C. Jack. Price 6/- net.) 

 Ponds and puddles have a fascination for the young ; 

 and, if some knowledge of the many interesting creatures 

 which live their life in small volumes of water is acquired, 

 the interest remains or increases in after-life. Mr. Ash's 

 little work, which is one of the series produced at the cost 

 of sixpence by Messrs. Jack, under the title of " The People's 

 Books," gives an account of the inhabitants of our ponds. 

 It is written in a light, not to say even jocular, vein, and 

 gives a good idea of what the enthusiast may expect to 

 find. Microscopic plants, infusoria, insects, spiders, mites, 

 aquatic worms, and amphibians are among the subjects 

 which are considered. We do not like to see Latin names 

 printed in ordinary Roman type, and zoologists do not use 

 capital letters for specific names ; still these are matters 

 which will not affect the general reader, who will find much 

 that is attractive in " Pond Life." 



W. M. W. 



NOTICES. 



THE FLEMISH SYSTEM OF POULTRY-KEEPING. 

 - — Country Life asks us to announce a series of articles 

 which will shortly appear in its columns by Madame Albert 

 Jasper on " The Flemish System of Poultry-keeping." 



THE " LONDON " MICROSCOPE.— We have received 

 from Messrs. R. & J. Beck a leaflet showing three models of 

 their " London " microscope, with the various objectives 

 and condensers suggested for use with them, the whole 

 being set out in such a way, with each item priced separately, 

 that anyone can tell at a glance what any particular outfit 

 would cost. 



COCKROACHES AT THE ZOOLOGICAL GARDENS. 

 — On February 23rd, at the meeting of the Zoological 

 Society of London, Dr. P. Chalmers Mitchell, F.R.S., F.Z.S., 

 Secretary to the Society, exhibited mounted examples of 

 three species of Cockroach — Periplaneta americana, P. 

 orientalis, and Phyllodromia germanica — all of which had 

 established themselves in different houses in the Society's 

 Gardens, and stated his wish that some naturalist would 

 endeavour to work out the causes of the selective distribution 

 of these insects. 



PHOTO-MICROGRAPHY.— At the end of the course of 

 lectures on Photography which Mr. E. Senior is delivering 

 at the South Western Polytechnic Institute he will give 

 six practical demonstrations on Photo-micrography on 

 Monday evenings, from 7.30 to 9.30, beginning on 

 May 3rd. At these demonstrations special attention will 

 be given to the photographing of etched surfaces of metals 

 and alloys (metallography), but the course will also be 

 arranged to suit the requirements of students of geology, 

 botany, and so on, and of those wishing to use their own 

 microscopes to obtain photographic records of objects. 

 It is advisable that students joining this course should 

 possess an elementary knowledge of photographic manipu- 

 lation. The fee for the course is 2 /6. 



A NEW PHOTOGRAPHIC PLATE.— A new plate has 

 been introduced by Ilford, Limited, for the use of those 

 engaged in Press - photography : it combines extreme 

 rapidity with quick development, quick fixation, and quick 



drying, and should prove valuable to those photographers 

 who practise this class of work. It is supplied at popular 

 prices, and a sample for testing purposes will be forwarded 

 post free upon receipt of a professional card. The plate is 

 known as the " Ilford Press plate." 



BOXWOOD FROM SOUTH AFRICA.— Our chief 

 supplies of boxwood for many years have been drawn from 

 the countries bordering on the Black and Caspian Seas. 

 These supplies have now been cut off, so that boxwood is 

 difficult to obtain and expensive to buy. The Imperial 

 Institute has recently examined the wood of Buxus 

 Macowani from South Africa. Several firms using box- 

 wood have also tested it, and the general opinion being 

 favourable, the Imperial Institute has suggested to the 

 Government of the Union of South Africa that it would 

 be well to place a trial shipment of this South African 

 boxwood on the London market. 



GLASS APPARATUS FOR EDUCATIONAL PUR- 

 POSES. — Sir Alexander Pedler has sent us, on behalf of the 

 British Science Guild, a joint report of the Education and the 

 Technical Education Committees on the provision of glass 

 apparatus for educational purposes. The Joint Committee 

 has been endeavouring to obtain assurances of support for 

 British makers of educational glassware after the war as 

 well as now, and has also collected information respecting 

 the principal types and size of glass apparatus which is 

 in greatest demand. Seventy-one per cent, of the head 

 masters of the schools represented on the Head Masters' 

 Conference have authorised their science staffs to purchase, 

 as far as possible, only British-made glass apparatus during, 

 and for a period of three years after the conclusion of, the 

 war. In other directions fewer definite replies have been 

 received, owing to the fact that committees and boards have 

 to be consulted before an answer can be given. Another 

 report deals with the manufacture of optical instruments, 

 and we most heartily endorse the suggestion that the 

 Government should undertake the necessary research that 

 must be carried out before optical glass suitable for micro- 

 scope and photographic lenses, equal to that made at 

 Jena, can be produced in England. 



