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as being most characteristic of their authorTexsome interesting results showing the con
TENSILE . in his capacity of a scientific and mathe. matical inquirer.”
nection between the electric resistance of iron The papers range over a period of fully wires and their state of strain have been comtwenty years, and are eminently noticeable for municated by Mr. W. H. Johnson, B. Sc., to their high scientific value, both as regards the the Manchester Literary and Philosopbical matter treated of and the admirable method of Society. The wires were tested for their re: the treatment. The papers number 37 in all, sistance by means of a Wheatstone balance and have been grouped into three great divi- with reflecting galvanometer of low resistance, sions with the object of classifying kindred and for their tensile stress by an apparatus subjects.
similar in principle to a steelyard weighing In looking at the bulky volume now issued, machine. A series of measurements were and which, after all, contains only a selection made upon different varieties of iron wire, from the various contributions of Professor beginning with pure iron smelted and worked Rankine, we are forcibly impressed with the throughout with charcoal, and ending with mental power, energy, and perseverence, re highly carbonized steel wire. The results quired in the author during his term of arduous show that charcoal iron has the least electrical pursuit of knowledge for the working out of resistance, or about one-half that of piano results so profound in their speculations, and steel ; and it is noticeable that the resistance so varied in their character; and as we see his regularly increases as the impurities augment. features depicted before us in the engraving, Annealed steel, which comes about midway which so suitably prefaces the subject matter, between pure charcoal iron and piano wire in we long “for the touch of the vanished hand the amount of carbon it ɔontains, is also interand the sound of the voice that is still.” mediate 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 puddied 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 bardening and tempering increase the resistafter years, those who are still working in the ance of the metal to the passage of the elecsame 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 bas 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 proporticnate to their electric conductstract of the paper, forms a titting 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 Reciero in conductivity. Engineering.
T a meeting of the Manchester Association MISCELLANEOUS.
of Engineers, a paper was read on the
8th inst., by W. H. Bailey, on “Recent MethA PPARATCS FOR MEASURING THE COMPAR- ods of Testing Portland Čement,” in which he
ATIVE STRENGTH OF BROKEN STONES. | described a number of testing machines, and - The French Government, after having made in calling attention to the enormous quantity various experiments, have adopted an appa- of cement now used in hydraulic and other ratus for testing the relative toughness and engineering works, showed the necessity for resistance of broken stones suited for macada- the most careful and frequent testing of all mizing roads. It consists of two hollow cyl. cement used on any work. inders, mounted on the same shaft, in an inrial selected for the basis of comparison tis. In connection with the Ribble Navigation
scheme, a meeting of a committee of the introduced; into the other, the material to be Preston Town Council, formed to negotiate tested. The cylinders are slowly turned on with the Ribble Navigation Company, has been their axis for å given time; after which they held, at which it was decided to carry on ne are emptied of their contents, and the respeci- gotiations with the company; and it is expected ive quantities of stone reduced to powder that next session the corporation will be able are weighed. The ratio of these weights to obtain an Act of Parliament for the transfer constitutes the coefficient of wear. The rela- of the stock of the company and the whole untive wears thus determined have been proved to dertaking to the corporation. harmonize with the results of wear in the road. pieces of stone
to be made by the
made to pass through a ring gauge, 6 centi- tons of Tees slag bricks made from blast fur. metres, or 2.36 inches in diameter. – Abstracts nace slag, as metalling for the highways inProc. of Cio. Eng.
stead of whinstone.
One Volume, 8vo., Cloth Extra. 169 Pages. 96 Illustrations. $2.50.
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PLATTNER'S BLOW-PIPE ANALYSIS. PRESCOTT'S PROXIMATE ORGANIC
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CHEMISTRY. IATTWOOD'S PRACTICAL BLOW
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FUEL: Combustion & Economy. ELECTRO MAGNETIC
Consisting of Abridgements of
WITH EXTENSIVE ADDITIONS ON
D. KINNEAR CLARK, C, E.,
• The Economy of Fuel,”
A. E. LORING.
A PRACTICAL TELEGRAPHER,
INTRODUCTION. COAL, COKE, WOOD, PEAT, PETROLEUM &c
It has been the aim of the author in the
preparBY THE EDITOR,
ation of this little book, to present the principles
of the Electro Magnetic Telegraph, in a brief, C. E., concise manner, for the benefit of practical oper.
ators and students of telegraphy. The works on 12mo. Cloth, Illustrated. Price, $1.50. besides being expensive, have contained Price, $1.50. telegraphy, which have thus far been presented,
is useless, or which is not in a form to be readily D. VAN NOSTRAND,
understood by young and inexperienced telegraphPublisher,
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Positive and Negative. Conductors and Non-Conduc-
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Part II.-The Morse TELEGRAPH.-Fundamental Prin. books, now comprising over Two Hundred ciple. Telegraph Circuits. Intermediate offices. The
Local Circuit. Ground Wires. The Key. The Relay. distinct works in almost every department of The Sounder. Main Line Sounders. The Box Relay.
Cut Outs. The Switch Board. Other Switches. Science, Art and Education, are recommended Lightning Arresters. Loops. Arrangement of Offices.
Arrangement of Batteries. Repeaters. to the notice of Engineers, Architects, Build Part 111.-BATTERIES.-Grove Battery. Carbon Bat.
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APPENDIX.-Suggestions and Exercises for Learners.
Rudimentary Scientific Series
Manual of Practical Chemistry;
THE ANALYSIS OF FOODS,
THE DETECTION OF POISONS. By ALEXANDER WYNTER BLYTHE, M.R.C.S., F.C.S.
Second Division-Detection of Poisons. 1. Introductory.
1. Introductory. 2. Wheaten Flour and Bread.
2. Poisons detected mainly by methods of 3. Butter-Cheese.
distillation. 4. Tea-Coffee-Cocoa.
3. Alkaloids and Poisonous vegetable principles 5. Alcohol – Alcoholic Liquors.
separated for the most part by alcoholic 6. Vinegar.
solvents. 7. Mustard-Pepper, &c.
4. Animal Poisons,
5. Inorganic Poisons.
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