as being "most characteristic of their author in his capacity of a scientific and mathe matical inquirer." The papers range over a period of fully twenty years, and are eminently noticeable for their high scientific value, both as regards the matter treated of and the admirable method of the treatment. The papers number 37 in all, and have been grouped into three great divisions with the object of classifying kindred subjects. In looking at the bulky volume now issued, and which, after all, contains only a selection from the various contributions of Professor Rankine, we are forcibly impressed with the mental power, energy, and perseverence, required in the author during his term of arduous pursuit of knowledge for the working out of results so profound in their speculations, and so varied in their character; and as we see his features depicted before us in the engraving, which so suitably prefaces the subject matter, we long "for the touch of the vanished hand and the sound of the voice that is still." TE ENSILE STRAIN AND ELECTRIC RESISTANCE. Some interesting results showing the connection between the electric resistance of iron wires and their state of strain have been communicated by Mr. W. H. Johnson, B. Sc., to the Manchester Literary and Philosophical Society. The wires were tested for their resistance by means of a Wheatstone balance with reflecting galvanometer of low resistance, and for their tensile stress by an apparatus similar in principle to a steelyard weighing machine. A series of measurements were made upon different varieties of iron wire, beginning with pure iron smelted and worked throughout with charcoal, and ending with highly carbonized steel wire. The results show that charcoal iron has the least electrical resistance, or about one-half that of piano steel; and it is noticeable that the resistance regularly increases as the impurities augment. Annealed steel, which comes about midway between pure charcoal iron and piano wire in the amount of carbon it oontains, is also intermediate in point of electrical resistance. Anl To his old students, and to scientific men nealing considerably diminishes the electricaeverywhere, we need not commend the volume resistance of puddled iron wire. The breaknow published, as we are sure they will readily ing strain and the resistance are also found to appreciate the memorial now offered to one so increase together in a fairly regular manner. well known in the scientific world. We think, Annealing is found to diminish the resistance however, that the publication of such collec- of bright steel wire about 1 per cent., while tions of papers has even a higher value, as, in hardening and tempering increase the resistafter years, those who are still working in the ance of the metal to the passage of the elec same fields have in such volume a record of the tric current. With regard to torsion, the tests steps trod by their predecessors, serving at show that the electrical resistance is, roughly once as an incentive to further investigation speaking, inversely proportional to the numand pointing out what has already been accom- ber of twists in the length of 8 in. The implished. In the present volume we have also portance of electric conductivity in boiler an excellent biographical sketch written by plates is pointed out by Mr. Johnson in his Professor Tait, which, with the editor's paper. The heat conductivity of metals is preface, containing a carefully prepared ab- nearly proportionate to their electric conductstract of the paper, forms a fitting introduc-ivity, and, as boiler plates should conduct heat tion to this highly important addition to our well, they ought also to have a high electric scientific literature.-Abstract of a Review in conductivity. Engineering. A MISCELLANEOUS. PPARATUS FOR MEASURING THE COMPARATIVE STRENGTH OF BROKEN STONES. -The French Government, after having made various experiments, have adopted an apparatus for testing the relative toughness and resistance of broken stones suited for macadamizing roads. It consists of two hollow cylinders, mounted on the same shaft, in an in position. Into one of these, the mate Ta meeting of the Manchester Association A of Engineers, a paper was read on the 8th inst., by W. H. Bailey, on "Recent Methods of Testing Portland Cement," in which he described a number of testing machines, and in calling attention to the enormous quantity of cement now used in hydraulic and other engineering works, showed the necessity for the most careful and frequent testing of all cement used on any work. N connection with the Ribble Navigation elmedeposit for the basis of comparison is I conne, a meeting of a committee of the introduced; into the other, the material to be tested. The cylinders are slowly turned on their axis for a given time; after which they are emptied of their contents, and the respective quantities of stone reduced to powder are weighed. The ratio of these weights constitutes the coefficient of wear. The relative wears thus determined have been proved to harmonize with the results of wear in the road. The pieces of stone selected for trial are as nearly uniform in size as is for tical, er made to pass through a ring gauge, 6 centimetres, or 2.36 inches in diameter. - Abstracts Proc. of Civ. Eng. Preston Town Council, formed to negotiate with the Ribble Navigation Company, has been held, at which it was decided to carry on negotiations with the company; and it is expected that next session the corporation will be able to obtain an Act of Parliament for the transfer of the stock of the company and the whole undertaking to the corporation. ,』 ' A rough-in Cleveland made by the Guis TRIAL is about to be One Volume, 8vo., Cloth Extra. 169 Pages. 96 Illustrations. $2.50. CHAPTER IV. Incandescent Lamps. CHAPTER V. Carbons for Incandescent Lighting. CHAPTER VI and VII. New Forms of Lamps. CHAPTER VIII. Preservation of Incandescent Carbons. CHAPTER IX. Division of Current and Light. CHAPTER X. Regulators and Switches. CHAPTER XI. General Distribution. CHAPTER XII. Commercial Aspects. D. VAN NOSTRAND, Publisher, 23 Murray and 27 Warren Streets, New York. *Copies sent by mail, post paid, on receipt of price. VALUABLE WORKS ON CHEMISTRY. ANALYSIS. 12mo. Cloth. $1.75. PLATTNER'S BLOW-PIPE ANALYSIS. | PRESCOTT'S PROXIMATE ORGANIC Third Edition. Revised. 568 pages. 8vo. Cloth. $5.00. PLATTNER'S MANUAL OF QUALITATIVE AND QUANTITATIVE ANALYSIS WITH THE BLOW-PIPE. From the last German edition, revised and enlarged. By Prof. TH. RICHTER, of the Royal Saxon Mining Academy. Translated by Professor H. B. CORNWALL; assisted by JOHN H. CASWELL. With eighty-seven wood-cuts and Lithographic Plate. NAQUET'S LEGAL CHEMISTRY. Illustrated. 12mo. Cloth. $2.00. LEGAL CHEMISTRY. A Guide to the Detection of Poissons, Falsification of Writings, Adulteration of Alimentary and Pharmaceutical Substances; Analysis of Ashes, and Examination of Hair, Coins, Fire-arms, and Stains, as Applied to Chemical Jurisprudence. For the Use of Chemists, Physicians, Lawyers, Pharmacists, and Experts. Translated, with additions, including a list of Books and Memoirs on Toxicology, etc., from the French of A. NAQUET. By J. P. BATTERSHALL, Ph.D., with a Preface by C. F. CHANDLER, Ph.D., M.D., LL.D. PLYMPTON'S BLOW-PIPE ANALYSIS. 12mo. Cloth. $1.50. THE BLOW-PIPE: A Guide to its Use in the Determina tion of Salts and Minerals. Compiled from various sources, by GEORGE W. PLYMPTON, C.E., A.M., Pro, fessor of Physical Science in the Polytechnic InstituteBrooklyn, N. Y. PYNCHON'S CHEMICAL PHYSICS. New Edition. Revised and enlarged. Crown 8vo. Cloth. $3.00. INTRODUCTION TO CHEMICAL PHYSICS: Designed for the Use of Academies, Colleges, and High Schools. Illustrated with numerous engravings, and containing copi. ous experiments, with directions for preparing them. By THOMAS RUGGLES PYNCHON, M.A., President of Trinity College, Hartford. ELIOT AND STORER'S QUALITA TIVE CHEMICAL ANALYSIS. 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Revised, with the co-operation of the Authors, by WILLIAM RIPLEY NICHOLS, Professor of Chemistry in the Massachusetts Institute of Technol- 8vo. Cloth. 188 pages. Illustrated. New and Enlarged ogy. RAMMELSBERG'S CHEMICAL ANALYSIS. 8vo. Cloth. $2.25. GUIDE TO A Course of Quantitative CHEMICAL ANALY- 'ATTWOOD'S PRACTICAL BLOWPIPE ASSAYING. 12mo. Cloth. Illustrated. $2.00. edition. $1.50. D. VAN NOSTRAND, Publisher, 23 Murray and 27 Warren Streets, New York. Copies sent by mail, post-paid, on receipt of price. Rudimentary Scientific Series These highly popular and cheap series of books, now comprising over Two Hundred distinct works in almost every department of Science, Art and Education, are recommended to the notice of Engineers, Architects, Builders, Artisans and Students generally, as well as to those interested in Workmen's Libraries, Free Libraries, Literary and Scientific Insti tutions, Colleges, Schools, Science Classes, &c., &c. Fully illustrated by wood-cuts where necessary. Full list, with prices, sent on application. D. VAN NOSTRAND, Publisher, 23 Murray and 27 Warren Sts., N.Y. TELEGRAPH, BY A. E. LORING. A PRACTICAL TELEGRAPHER. INTRODUCTION. It has been the aim of the author in the preparation of this little book, to present the principles of the Electro Magnetic Telegraph, in a brief, concise manner, for the benefit of practical operators and students of telegraphy. The works on telegraphy which have thus far been presented, ers. besides being expensive, have contained much that is useless, or which is not in a form to be readily understood by young and inexperienced telegraphAlthough this little work must be acknowledged incomplete, it is hoped that it may go far toward supplying the deficiency which has existed; or, at least, serve as a stepping-stone to the study of the more complete works on electricity and telegraphy. THE AUTHOR. CONTENTS. PART I.-ELECTRICITY AND MAGNETISM.-ElectricityPositive and Negative. Conductors and Non-Conductors. Galvanic Batteries. Galvanic Circuits. Electrical Quantity and Intensity. Resistance. ElectroMotive Force. Haskin's Galvanometer and its Uses. Ohms Law. Measurement of Currents. Measurement of Resistance. Speed of the Current. Divided Circuits. Electro-Magnets. Residual Magnetism. Proportion of Electro-Magnets to Circuits. Intensity and Quantity Magnets. PART II.—THE Morse TelegRAPH.-Fundamental Prin. ciple. Telegraph Circuits. Intermediate offices. The Local Circuit. Ground Wires. The Key. The Relay. The Sounder. Main Line Sounders. The Box Relay. Cut Outs. The Switch Board. Other Switches. Lightning Arresters. Loops. Arrangement of Offices. Arrangement of Batteries. Repeaters. PART III.-BATTERIES.-Grove Battery. Carbon Battery. Amalgamation of Zincs. Daniell Battery. Hin Battery. Other Forms of Battery. Battery Insulators. PART IV.-PRACTICAL TELEGRAPHY.-Alphabet and Numerals. Adjustment of Instruments. Testing Telegraph Lines. Breaks. Escapes. Grounds. Crosses. PART V.-CONSTRUCTION OF LINES.-The_Conductors. The Insulators. Fitting up Offices. Ground Wire Connections. Private and Short Lines. APPENDIX.-Suggestions and Exercises for Learners. Paper Boards, 50 cents, Cloth, 75 cents, Morocco, $1.00. D. VAN NOSTRAND, Publisher, 23 Murray Street, New York. **Copies sent by mail,post paid, on receipt of price. A Manual of Practical Chemistry; THE ANALYSIS OF FOODS, AND THE DETECTION OF POISONS. By ALEXANDER WYNTER BLYTHE, M.R.C.S., F.C.S. One Volume, Crown 8vo., 568 Pages. Price, $3.50. D. VAN NOSTRAND, Publisher, 23 Murray & 27 Warren Sts., New York, Copies sent by mail, post paid, on receipt of price. THE Journal of the Franklin Institute, DEVOTED TO SCIENCE AND THE MECHANIC ARTS. ESTABLISHED IN 1826. The only Technological Journal published in the United States, without private pecuniary interest. Its object is to encourage original research, and disseminate useful knowledge in all matters relating to the practical application of science, but more especially to engineering and the mechanical arts. The JOURNAL is issued in monthly numbers, of eighty pages each, largely illustrated, forming two volumes annually. The number for December, 1880, completes the One Hundred and Tenth volume. Hereafter its value will be greatly increased by its containing more original matter: by more attention and space being given to the publication of articles condensed from foreign and domestic scientific and technical periodicals, with ample_references. More space will also be given to the transactions of the Institute, thus rendering it of special interest to members. Communications for the Journal, and business letters, should be addressed to the Secretary of the Franklin Institute, Philadelphia, Pa. |