At Last A Precision Tachometer The Van Sicklen Chronometric The Tachometer Timed by an Elgin Watch 66 Universal in Application Reads 20 to 2500 R.P.M. on Dial Accurate Within 5 R.P.M. on Total Scale Durable Unaffected by Wear Accurate as an Elgin" For Full Description Send for Bulletin 818 Central Scientific Company 460 East Ohio Street CHICAGO, U. S. A. (Lake Shore Drive, Ohio and Ontario Streets) No. 30. No. 31. For fine precipitates. Very rapid. Heavy. For the finest precipitates. For gelatinous and large particle precipitates. Extremely rapid. Single Acid Washed For fine precipitates. Very rapid. For gelatinous and large_particle (not fine) precipitates. The most rapid Filter Paper made. Double Acid Washed No. 40. For general quantitative work. No. 41. Very rapid. Not for use with fine precipitates. No. 42. For extremely fine precipitates, with or without vacuum. No. 44. Lower ash than any above mentioned. For the most exacting analyses. No. 50. Hardened. For filtering corrosive liquids, etc. Sole Representatives in the U. S. A. and Canada H. REEVE ANGEL & CO., Inc. 7-11 Spruce Street New York FRY THE GREAT WAR HAS TAUGHT AMERICAN LABORATORY OF DISTINCTLY SUPERIOR QUALITY. IF YOUR DEALER WILL NOT SUPPLY YOU, WE WILL SELL DIRECT. BOOKLET AND PRICE LIST MAILED UPON REQUEST. H. C. FRY GLASS CO. ROCHESTER PENNSYLVANIA (Being the fourth, and last, of a series of advertisements by Eimer & Amend, setting forth their RY OF THE chief attainments during the war.) PEABODY MUSEUM The uncommon achievements of our instrument shop during the past few years readily fall into FIRSTLY, the experimental work on various apparatus for use of the SECONDLY, the rebuilding and refinishing of imported apparatus—some WORK ORDERED by the Government and done directly for it was perhaps the most interest- THE SUGAR industry was greatly inconvenienced by the inability to procure French or German polariscopes. When the consequences had assumed a serious aspect, we undertook to remodel a Schmidt & Haensch instrument, including repolishing, cementing and repairing of the prisms. The results was so highly pleasing to our customer that we secured a continuous flow of orders of this kind from all over the sugar-producing sections of the United States, Cuba, and Porto Rico. To the best of our knowledge, all the polariscope observation tubes produced in the world during the past two years (except those, if any, turned out by our enemies) were made by us. AMONG precision instruments of similar class which we have taken the time to dismantle and remodel, let us mention Wanner pyrometers and Zeiss microscopes, including their objectives. WE HAVE manufactured COMPLETELY Beckmann boiling point and freezing point apparatus; Duboscq colorimeters, quite like the original French, and, we think, better; Juerst ebullioscopes, to replace the Salleron; and also a number of other intricate physical apparatus. IN ADDITION to these, we have maintained and increased our normal output of such well known specialties as the three types of Young's specific gravity instruments (two styles embodying displacement plummets of incomparable accuracy) excelling in sensibility the highest class of analytical balance; Kimley Electro-Analysis apparatus; Gramercy Stirrers, and many others. THE CAPABILITIES and the facilities that raised this shop and its work above others of its kind are now available for the solution of problems like in nature to those indicated by the foregoing resume. EIMER & AMEND NEW YORK AND PITTSBURGH Your Laboratory Needs of every description can be met by us to your entire attention. Originally laboratory workers ourselves, we have Practically the entire Bausch & Lomb organization Catalogs are now in course of preparation for early The Will Corporation A New Agricultural Text FARM HORTICULTURE By GEORGE W. HOOD, M.Sc. Associate Professor of Horticulture, University of Nebraska 12mo, 339 pages with 142 engravings. Cloth, $2.50 net Written primarily as an elementary text, arranged and developed to meet the needs of the undergraduate collegiate student, as well as those studying agriculture in the secondary agricultural schools. Judging by the letters received from Professors of Agriculture in our leading colleges, the author has succeeded in his aim to produce a thoroughly practical book that would fully meet these requirements. Teachers of agriculture and horticulture will find it suitable as a text to cover the general field. It gives information about those practices which many people desire but which cannot be found in any single text. It will be a guide to any farmer or city man on the important subjects in horticulture. The diagrams and plans for gardens of varying sizes are most helpful and clear, as are the chapters on The Seed and Its Needs, Cultivation and Tillage, Budding and Grafting, Marketing, the various Pests and how to Combat Them. Interesting also are the special chapters devoted to the Strawberry, the Bush Fruits, the Brambles, the Grape, the Pome Fruits, the Stone Fruits, the Citrus Fruits and Beautifying the Home Grounds. |