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Remarkable Solar Protuberance.- About 11 A.M. on the 30th of August L. Thollon noticed a small and very brilliant luminous jet near the sun's equator. About 12 h. 45 m. it had attained prodigious proportions, while still preserving the form of a luminous jet from a direction nearly normal to the border of the sun. The result of frequent measurements indicated a height of protuberance at least equal to half of the sun's radius, or more than 200,000 miles. Whilst the lower and middle parts of the protuberance gave a deviation of the C line towards the violet end of the spectrum the summit presented a similar deviation towards the red end. - Compt. Rend.

C. Temperature of Least Resistance in Steel.-It is well known that a steel that is very flexible when cold breaks at the blue annealing temperature. It has generally been considered that the purer the iron is the less subject it becomes to this defect, but the workmen of the Ural mountains, who use irons of remarkable purity, have often observed the same fact. Mr. Adamson has found that the metal becomes powdery at a temperature between 260° and 370°C. (500 and 698°F.) or the temperature at which willow twigs take fire. This phenomenon seems to explain a large number of accidents, as for example the breaking of tires under the action of brakes and the fracture of riveted moulds and of machine arbors which become heated by friction. -- Ann, du Gen. Cic.

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Behavior of Gas under High Pressures.-- The following are some of the results of Amagat's investigations upon the dilatation and compressibility of gases under extreme pressures. 1. The coefficient of dilatation, for temperatures not greatly exceeding the critical temperature, increases with the pressure until it reaches a maximum and then decreases indefinitely. 2. This maximum corresponds to the pressure at which the product p v is a minimum. 3. The maximum diminishes with the increase of temperature and finally disappears. 4. At a temperature sufficiently high the compressibility is represented by the formula p (v a) = a constant; a being the smallest volume that the fluid can occupy; for each gas a has a special value. The values of a for three important gases, at the freezing point and under normal pressure, are as follows: Carbonic acid .00170, ethylene .00232, hydrogen :00078.-- Compt. Rend.

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Franklin Institute.

HALL OF THE INSTITUTE, June 15th, 1881. The stated meeting was called to order at 8 o'clock P.M., the President, Mr. William P. Tatham, in the chair.

There were present 113 members and 59 visitors.
The minutes of the last meeting were read and approved.

The Actuary presented the minutes of the Board of Managers, and announced that at the last meeting 16 persons were elected members of the Institute; also, that upon the recommendation of the Committee on Instruction the Board had decided to create three professorships, viz.: on mechanics, physics, and chemistry; also, that a chemical section had been authorized on the petition of the requisite number of members of the Institute.

On motion of Mr. Washington Jones the regular order of business was suspended, and the Institute proceeded to take a vote upon the repeal of Section 4 of Article III of the By-Laws, and the alteration of Section 1 of Article I, as published in the JOURNAL last month. Both were unanimously adopted, and the confirmation of the latter submitted to a vote of the stockholders present, with a similar result.

The committee on the subject of a reorganization of the Committee on Science and the Arts reported progress.

The following donations to the Library have been received:

Annual Report of the Chief Engineer of the Water Department for 1880.

From the Chief Engineer. Report of the Commissioner of Internal Revenue for year ending June, 1879.

From the Commissioner. Thirtieth Annual Report of the Indiana State Board of Agriculture, 1880.

From the Board. Reports of the Auditor-General on the Finances of the Commonwealth of Pennsylvania for 1878–80.

From Auditor-General, Harrisburg. Annual Reports of the Secretary of Internal Affairs. Parts 1 and 2, 1879 and 1880.

From the Secretary, Harrisburg. Annual Report of the Secretary of Internal Affairs. Part 4, 1879– 80.

From the Secretary, Harrisburg. Annual Report of the Chief Engineer U. S. A. for 1880.

From the Chief of Engineers.

Documents relating to the Colonial History of the State of New Jersey. By W. A. Whitehead. Vol. 1. 1631-87.

From the Author. Transactions of the Department of Agriculture of Illinois. Vols. 9 and 11. 1871 and 1873.

From E. Hiltebrand. Wood-working Tools ; How to Use Them. Boston, 1881.

From the Smithsonian Institute, Washington, D. C. Transactions of the Society of Engineers for 1880.

From the Society, London. Specifications and Drawings of Patents for September, 1880.

From the United States Patent Office. Account of the Operations of the Great Trigonometrical Survey of India. Vol. 6. From His Excellency the Viceroy and Governor-General of India.

Transactions and Proc. of New Zealand Institute. Vols. 1, 5 to 10, and 13.

Index to Vols. 1 to 8.

Catalogue of Tertiary Mollusca and Echinodermata of New Zealand. Wellington, 1873.

Geological Report on the Waikato District.
Hand Book of New Zealand. Wellington, 1880.
Appendix to Official Catalogue International Exhibition, Sidney.
Wellington, 1880.

Palæontology of New Zealand. Part 1. Wellington, 1880.
Fifteenth Annual Report on the Colonial Museum, etc., 1879–80.
Catalogue of Exhibits International Exhibition. Melbourne, 1880.
Reports of Geological Explorations during 1877–79.
Catalogue of Stalk and Sessile-eyed Crustacea of New Zealand.
Catalogue of the Echinodermata of New Zealand.

From the New Zealand Institute, Wellington, N. Z. General Index to the Fourth Ten Vols. of Jour. of Royal Geographical Society. 1881.

From the Society. Memoirs of the Literary and Philosophical Society of Manchester. Vol. 6. 30 Series.

Proceedings of the Literary and Philosophical Society of Manchester. Vols. 16-19.

From the Society. Official Catalogue of the British Section Paris Univ. Exhibition, 1878. 2d Ed. 4 Pts. Remarks on the Manufacture of Glucose by the Johnson Process.

From Harrison Bros, & Co. Photometric Measurements of the Variable Stars. By E. C. Pickering. Cambridge, 1881,

From the Author.

Hygiene of Emigrant Ships. By T. J. Turner. 1880.

Fourteenth Annual Report of the Peabody Institute of the City of Baltimore. 1881.

From the Institute. Catalogues des Brevets, 1878-80.

From the French Patent Office. Report upon Certain Museums for Technology, Science and Arts. By A. Liversidge. Sidney, 1880.

Reports of Council of Education upon the Condition of Public Schools, 1879. Sidney, 1880.

Journal of the Royal Society of New South Wales. Vol. 13. 1879.

Transactions of the Royal Society of New South Wales for 186870 and 1873.

Annual Report of the Department of Mines, with Maps of New South Wales, for 1878 and 1879.

From the Royal Society of New South Wales. Abhandlungen der K. K. Geol. Reich. Vol. 12. Part 2. Die Gasteropoden.

From K. K. Geol. Reich., Vienna. Programm der Grossherzoglich-Badischen Polytechnischen Schule zu Karlsruhe für 1880–81.

From the School. Publications of Royal Instituto di studi superiori practici e di perfezionamento in Firenze.

(1) Colera Asiatica memoire del Dott Filippo Pacini (2) Origini Della Lingua Poetica Italiana Del Dott C. N. Caix. From the Institute.

Meteorological Observations recorded at Six Stations in India in 1879. Registers or Original Observations in 1880 for January to March.

From the Meteorol. Dept. Government of India. Anales del Instituto y Observatorio de Marina de San Fernando. By Don Cecilio Pujazon. Section 2. 1877 and 1878.

From the Institute. Dr. Robert Grimshaw read a paper on “ Percussion Rock Drills," illustrated by photographs of machines projected upon the screen. The paper is printed in this number of the JOURNAL.

Mr. Lorin Blodgett read a paper on “ Textile Fibres Under the Microscope,” illustrated by samples of them, and photographs of the same thrown

upon the screen; also images of the silkworms at work. The cocoons, etc., were furnished by the Women's Silk Culture Association. Mr. Blodgett, after briefly mentioning the importance of the subject upon which he had undertaken to speak, said that he did not purpose to repeat the admirable general directions to silk-growers given by the Women's Association, but simply to show what the silk fibre is, and how to handle it, so as to make it as valuable as the silks of Italy or France.

The fibre of silk as produced in the cocoon is a single, continuous and perfect fibre—the most perfect and durable of fibres, if properly treated ; and it must be treated as a single fibre throughout. Raw silk is a definite number, five to eight fibres, as reeled from the cocoons, adhering in a body by the gum of the cocoon remaining on them -apparently a single fibre, but really a bundle of eight, as shown in the figure, representing a thread of Chinese Tsatlees, the best of the Chinese raw silks.

All silk fibres must be reeled in bundles of not less than five nor more than eight; if reeled in single, double or even triple fibres, from as many cocoons, they cannot be used as regular silk.

Floss silk is of two kinds ; first, the light outer fibres of the cocoon, with the broken and imperfect fibres cleaned of gum, usually; but the better floss silk is reeled silk of not less than five cocoon fibres, not usually cleaned of gum, and not much twisted. This is more frequently called singles.

Tram is a combination of three threads, 15 to 24 original fibres, with more twist, 21 to 3 turns to the inch.

Organzine is made up of two threads, twisted 12 turns per inch to the left, then doubled with 8 turns per inch to the right. This is the standard quality of thread for the best silk goods.

All who reel silk should weigh 500 yards of the raw thread, made up of five single cocoon fibres, making 2500 yards of single fibre. If the hank so reeled is above or below the standard weight, a greater or less number of cocoons should be united in the one raw thread.

These definitions are given because they are absolutely essential to success on the part of the American grower. He cannot make anything but raw silk in the gum, as reeled in the manner described ; but he must know what the manufacturer who makes floss, tram and organzine demands, or his silk will be worth but one or two dollars per pound, when it should be worth six dollars per pound.

Spun silk is made from pierced cocoons, cocoon waste, and the waste mills using raw silk—that is, in its best form. It is carded and drawn with as much care as worsted wool, and forms a valuable element of many fabrics, particularly upholstery goods, trimmings and ornamental articles. All growers will, of course, have a part of their

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