BECBRO LABORATORY RHEOSTATS Screw Adjustment Type "BECBRO" Rheostats carried in stock include numerous different ratings. Included in the stock sizes are tubular types of lengths 20; 16; 8; the resistance element being Wire or Ribbon. Each tube has a slider adjustment which varies the resistance by very small steps from Zero to total value of the unit. The approximate total resistance of these stock rheostats varies from 0.3 ohm to 30,000 ohms per unit, and have corresponding current capacities of 25 amperes down to 0.1 ampere. Rheostats of more or less special construction include the Single Tube equipped with two rods and two sliders; Single and Double Tube equipped with Screw Adjustment (see cut); Double and Triple Tubes mounted as a Unit; Non-Inductive Wound Tubular and Stone Types. "BECBRO" Carbon Compression Rheostats with corresponding Normal Ratings of 250; 1000; 1500; 3000 Watts. You Don't Buy Laboratory Chemicals and Apparatus Just to Waste Them THE old practice of cluttering up laboratory work tables with valuable chemical reagents and samples is the direct cause of a large proportion of breakage and resultant material losses. Besides breakage, laboratory accuracy is often times affected by congested working space. The Schwartz Sectional System is to the laboratory what the Modern Letter File is to the Busy Office. Containers and apparatus of any size or shape are systematically and scientifically filed in dust-proof drawers which open and swing at an angle that exposes them to view the same as if they were on an open shelf. The work table is thus kept free from congestion, and the possibility of breakage and loss reduced to a minimum. Schwartz Cabinets are made in size to suit the needs of the smallest or the largest laboratories, special cabinets are made to fit special spaces. We index for you all the individual items you file in your Cabinet. Write for Booklet "S" Containing Illustrations and Prices. SCHWARTZ SECTIONAL SYSTEM Indianapolis, Indiana Compiled by HENRY D. HUBBARD U. S. Bureau of Standards, Washington, D. C. Every atomic characteristic revised according to the latest statistical information Additional fundamental data added including: "Quantum State of Last Added Electron" "Lowest Spectral Term of Normal State" Another new feature is the inclusion, along the side of the Chart, of paragraphs explaining the fundamental significance of the forty different features of atomic characteristics shown on the Chart. One of these charts should be in every laboratory or lecture room in both the Physics and No. 4854 Chart of the Atoms, according to Hubbard, complete with 24-page Key; size 42"x64"; lithographed in six colors; cloth-backed; mounted on double split rollers on top and bottom; complete $5.00 Send for our new 1927 Catalog "G"-480 pages. Many new illustrations with complete descriptions, prices, and interspersed with over one hundred historical and biographical sketches. PACIFIC COAST REPRESENTATIVES The work presents a definite study of those micro-organisms commonly encountered in medicine, comparative pathology, hygiene and public health. It is divided into six parts: Part I treats of general bacteriology, discussing the historical aspect, morphology, bacterioscopic methods and technic, vital activities of bacteria, cultivation and media, and their destruction. Part II is concerned with systematic bacteriology. Part III, distribution of bacteria. Part IV, in a chapter of 100 pages, covers infection and immunity. Part V is devoted to the spirochetes, while Part VI discusses infectious micro-organisms of undetermined character. By William W. Ford, M.D., Professor of Bacteriology, School of Hygiene and Public Health, Johns Hopkins American Illustrated Medical Dictionary 14th Edition New words-2000 of them-make their apearance for the first time in this new (14th) edition. Many of the definitions already in the book have been rewritten to conform to the latest accepted ideas; the illustrative feature of the book has been greatly enlarged by the addition of over 100 new line-cuts which bring out and emphasize important points in the text. This dictionary defines hundreds of words not defined in any other medical lexicon, bar none! Octavo of 1388 pages, with 427 illustrations, 107 in colors. Flexibly bound, thumb indexed. Howell's Physiology $7.50 net. Tenth Edition Since the last edition changes in our knowledge of physiology have taken place with great rapidity. Dr. Howell has observed these changes, weighed their importance, and, where desirable, has incorporated them. With a view to the practical application of the study, Dr. Howell has given main emphasis to facts and views which will be directly helpful in the study of general pathology. At the same time, however, he has included enough of modern research work to give an idea of the tendencies of present-day physiologic experimentation and study. By William H. Howell, M.D., Professor of Physiology in the School of Hygiene and Public Health, Johns ..SIGN AND MAIL THIS ORDER FORM TODAY.................. W. B. SAUNDERS COMPANY, West Washington Sq., Philadelphia Please send me the books checked (V), charging the amount to my account: Ford's Bacteriology, $8.50 net. American Medical Dictionary, $7.50 net. Howell's Physiology, $6.50 net. The Century Biological Series Robert Hegner, Editor Host-Parasite Relations Between Man and His Intestinal Protozoa BY ROBERT HEGNER, Ph.D. Professor of Protozoology in the School of Hygiene and Public Health of the Johns Hopkins University The purpose of this book is to gather together the more relevant data regarding the hostparasite relations of the intestinal protozoa of man and to present them in logical order in such a way as to bring out the state of our knowledge with special reference to the desirability of further studies. The book discloses the amazing inadequacy of the data available on the particular phases of protozoölogy with which it deals. It makes clear the need for more systematic and intensive research in the subject. In this new volume, re-edited and, in part, rewritten, is a selection from forty or fifty recent educational addresses, pertinently grouped by topics, with an entirely new introduction and closing chapter, making of the whole a clarifying and valuable compendium, of great general interest but indispensable to all educators and workers in this field. With portraits. 12mo. $2.50 From the Greeks to Darwin An outline of the development of the evolution idea. 8vo. 3d thousand. $2.75 Impressions of Great Naturalists With portraits. 12mo. 4th thousand. $2.50 Evolution and Religion in Educa tion The Fundamentalist controversy of 1922-25. 12mo. 12th thousand. Life History of Earth and Man $2.00 |