So 



HARDWICKE'S SCIENCE-GOSSIP. 



little manual circulating in this country. It is just 

 the book we are often asked to recommend : full and 

 clear in its detailed explanations. The headings of 

 the chapters are as follows : " Simple Microscopes" ; 

 " The Compound Microscope"; "Objectives and 

 Eye-pieces"; "Requisites for Work"; "How to 

 Work " ; " Advanced Manipulation " ; "To select a 

 Microscope " ; "Sub-stage Illumination " ; " Care of 

 a Microscope," and Appendix. 



The Optics of Photography and Photographic Lenses, 

 by J. Traill Taylor (London: Whittaker & Co.). 

 The author has for many years been editor of the 

 " British Journal of Photography," so that no other 

 man is better capable of writing such a useful manual 

 as that before us. It is eminently practical, and all 

 users of photographic lenses, both professionals and 

 amateurs, will be thankful to possess it. Indeed 

 there is scarcely a single detail which photographers 

 of all classes have to be acquainted with in the 

 prosecution of their art, which is not here clearly and 

 fully set forth. The following enumeration of the 

 chapters will give our readers some idea of Mr. 

 Taylor's praiseworthy little book : " What consti- 

 tutes Photographic Optics — Nature and Properties of 

 Light " ; " Photographic Definition, Real and Ideal — 

 Forms of Single and Achromatic Lenses"; "The 

 Cause of an Inverted Image " ; " Spherical Aberra- 

 tion " ; " The Nature and Function of the Diaphragm 

 or Stop " ; " Properties of Deep Meniscus Lenses — 

 Compensating Single Lenses ; " "The Optical Centre 

 of Single Lenses" ; " The Optical or Focal Centre of 

 a Combination"; "Single Achromatic Lenses"; 

 "Distortion, its Nature and Cure"; "Non- 

 distorting Lenses"; "Wide-angle Non-distorting 

 Lenses"; "Portrait Lenses;" "Rapid Landscape, 

 Group, and Copying Lenses " ; " Universal Landscape 

 Lenses" ; " Flare and the Flare Spot." The book 

 contains sixty-eight illustrations, and is usefully sup- 

 plied with a copious index. We cordially commend 

 it to all those of our readers who are interested in 

 the science and art of photography. 



Air and Water, by Prof. Vivian B. Lewes (London : 

 Methuen & Co.). This is a well-written, interesting 

 little book, one of the university extension series. 

 The author very successfully brings before his readers 

 the wonderful changes going on in our atmosphere, 

 and the still more marvellous work which water 

 performs in our nature. Prof. Lewes writes very 

 largely from a hygienic point of view. Readers will 

 find this little work useful at any time as a handy 

 book of reference on subjects connected with air and 

 water. The contents are as follows : "The History 

 of the Atmosphere " ; " The chief Constituents of the 

 Atmosphere " ; " The minor Constituents of the 

 Atmosphere " ; " The local Impurities of the Atmo- 

 sphere " ; "The Causes which tend to keep the 

 Composition of the Atmosphere constant"; "The 

 Air of enclosed Spaces and Ventilation" ; " Water 

 and its Composition" ; " The Determination of the 



Composition of Water " ; " The Properties of 

 Water"; "The Circulation of Water in Nature" ; 

 " The Impurities of Water " ; " The Purification of 

 Water." 



Tenth Annual Report of the United States' Geological 

 Survey, 188S-89 (Washington : Government Printing 

 Office). We have to acknowledge two more large 

 and handsomely got-up volumes, sent us by the 

 American Government, in striking contrast with the 

 beggarly niggardliness with which our own hides 

 the lights of its geological surveyors under a bushel. 

 Besides the Report of the Director, these volumes 

 contain the following memoirs : — " General Account 

 of the Fresh-water Morasses of the United States, 

 with a Description of the Dismal Swamp District of 

 Virginia and South Carolina," by Professor N. Shaler 

 (this paper is profusely and excellently illustrated) ; 

 " The Penokee Iron-bearing Series of Michigan and 

 Wisconsin," by R. D. Irving and C. R. Van-Hise 

 (numerous coloured maps and rock-sections) ; "The 

 Fauna of the Lower Cambrian or Olenellus Zone," 

 by C. D. Walcott (illustrated by fifty excellent plates, 

 besides woodcuts). This is one of the handsomest 

 volumes the Survey has hitherto published. One 

 volume of the Tenth Annual Report is entirely de- 

 voted to the subject of " Irrigation." 



Fifth Report of the United States' Entomological 

 Commission, on "Insects injurious to Forest and 

 Shade Trees," by Dr. A. S. Packard (Washington : 

 Government Printing Office). This is another of the 

 valuable volumes issued by the American Government, 

 the work of one of the most distinguished entomolo- 

 gists of the day. It is illustrated by 360 woodcuts 

 and 40 full-page plates, many of them coloured. All 

 the insects, chiefly Lepidoptera, which injuriously 

 affect forest-trees are here figured and described in 

 every stage of their development. The trees whose 

 insect enemies are described are the oak, elm, 

 hickory, black walnut, butternut, chestnut, locust- 

 tree, maple, cotton-wood, lime, birch, beach, wild 

 cherry, plum, thorn, crab-apple, mountain ash, ash, 

 willow, hackberry, alder, sycamore, pine, spruce, fir- 

 tree, larch, juniper, cedar, and Cyprus. It is one of 

 the most admirable volumes in every respect the 

 U.S.A. Commission has ever turned out. 



Annual Reports of the Smithsonian Institution, 

 vols. 1887-S9 (Washington: Government Printing 

 Office). These bulky volumes, which run to over 

 seven hundred pages each, are exceedingly useful to 

 a scientist, on account of their admirable progress in 

 scientific work for each year, as well as their full and 

 useful bibliography. In addition, each volume con- 

 tains a well-written review of some particular subject, 

 or translations of papers and addresses from the most 

 important foreign papers of each year. No more 

 entertaining and useful scientific annual appears. 



Systematic List of British Oligocene and Eocene 

 Mollusca in the British Museum of Natural History, 

 by B. B. Newton ; Catalogue of British Hymenoptera 



