Produced by Juliet Sutherland and the Online Distributed Proofreading Team at www.pgdp.net [Illustration] SCIENTIFIC AMERICAN SUPPLEMENT NO. 711 NEW YORK, AUGUST 17, 1889 Scientific American Supplement. Vol. XXVIII., No. 711. Scientific American established 1845 Scientific American Supplement, $5 a year. Scientific American and Supplement, $7 a year. * * * * * TABLE OF CONTENTS. I. AGRICULTURE.--How to Raise Turkeys.--A collection of hints and suggestions on the raising of the delicate fowls, so often the cause of trouble to farmers. 11364 Pear Duchesse D'Angouleme.--The history of the famous pear tree, with hints as to its culture and general treatment. 11362 II. BIOLOGY.--Development of the Embryo.--A note of some interesting biological researches.--By Prof. PREYER, of Berlin. 11365 The "Hatchery" of the Sun Fish.--A curious incident in the life history of the common sunfish.--1 illustration. 11363 III. CHEMISTRY.--On Allotropic Forms of Silver.--By M. CAREY LEA.--A continuation of this paper, containing one of the most important researches in the history of silver, with statement of interesting results attained. 11361 On the Occurrence of Paraffine in Crude Petroleum.--A valuable contribution to the history of paraffine, with reference to petroleum and ozokerite. 11361 Turpentine and its Products.--By EDWARD DAVIES.--A resume of the work done by chemists in the turpentine products. --The different compounds produced therefrom. 11361 IV. ELECTRICITY.--Electric Lighting at the Paris Exhibition. --The Oerlikon works.--A very exhaustive exhibition of electric apparatus described and illustrated.--12 illustrations. 11356 Magnetism in its Relation to Induced Electromotive Force and Current.--By ELIHU THOMSON.--A most impressive paper, bringing the obscure laws of magnetic induction within the understanding of all without the application of mathematics.--12 illustrations. 11354 The Ader Flourish of Trumpets.--One of the curiosities in telephony from the Paris exhibition, by which sounds are transmitted to a large audience.--4 illustrations. 11358 The Electric Motor Tests on the New York Elevated Railroad.--Abstracts of tests which were recently made of the Daft motor on the elevated railroad of this city. 11353 V. ETHNOLOGY.--Ancient Lake Dwellings.--Interesting abstract of what is known about lake dwellings, the history of their construction, and the "finds" made on the sites by archaeologists. 11363