ARCH+: Zeitschrift für Architektur und Urbanismus: ARCH+ : Zeitschrift für Architekten, Stadtplaner, Sozialarbeiter und kommunalpolitische Gruppen

Bibliografische Daten

Zeitschrift

Persistenter Identifier:: 1571051867188

Titel:: ARCH+: Zeitschrift für Architektur und Urbanismus

Erscheinungsort:: Aachen

Erscheinungsverlauf:: 1.1968-

Signatur:: Archiv IGMA; Universität Stuttgart, Institut für Grundlagen moderner Architektur und Entwerfen

Strukturtyp:: Zeitschrift

Sammlung:: Zeitschriften

Lizenz:: http://rightsstatements.org/vocab/InC/1.0/

Band

Persistenter Identifier:: 1571051867188_1984

Titel:: ARCH+ : Zeitschrift für Architekten, Stadtplaner, Sozialarbeiter und kommunalpolitische Gruppen

Jahrgang/Band:: 1984, Jg. 17, H. 73-78

Erscheinungsjahr:: 1984

Sprache:: deutsch

Strukturtyp:: Band

Standort:: Universität Stuttgart, Institut für Grundlagen moderner Architektur und Entwerfen

Lizenz:: http://rightsstatements.org/vocab/InC/1.0/

Sammlung:: Zeitschriften

Ausgabe

Titel:: Heft 77: Computer-Aided-Design

Strukturtyp:: Ausgabe

Teil

Titel:: CAD

Strukturtyp:: Teil

Artikel

Titel:: Der Mikrocomputer und die Dekane- und Abteilungsleiterkonferenz Architektur und Raumplanung

Autor:: Wertz, Elmar

Strukturtyp:: Artikel

Commer News} Liquids and Gases near they Critical Temperatures. 9 pyrogallic acid be strong, or a brown if that solution be vacuum and a movable cistern, suspended by a cord very weak (about I to 2 grms. per litre). Ihave found the overa pulley, and supported by a counterpoise. By rais- strength of the pyrogallic acid solution to vary in different ‘ng or lowering the cistern (which is connected to the specimens from about Io grms. to 50 grms. in I litre, while cube by an india-rubber pipe) the mercury column is also the quantity of silver nitrate varied 10 to 60 grms. per -aised or lowered, and the length of the vacuum—that is, litre, and that of the copper salt from oto 13 grms. per :he resistance of the shant—altered. litre.. Two specimens of this dye, obtained from different Mr. MAcFARLANE GRAY read a paper ‘On Specific makers, had this solution of metals made alkaline with Heats calculated from Entropy.” The author arrives at smmonia, a sufficiency being used to just re-dissolve the some remarkable results, which will be found in his paper hydrates, as before mentioned. in the Proceedings of the Society. He also explained a new graphic method of representing entropy. Mr, CLARK communicated a paper ‘ On the Behaviour of Liquids ard Gases near their Critical Temperatures.” When a sealed tube containing a capillary tube dipping into alcohol, ether, or sulphurous anhydride, is heated, the liquid sinks in the capillary tube and rises by expansion in the outer tube. Between 2 and 3° C. below the critical temperature of these liquids both surfaces become level, and, on continuing to heat, the concave capillary meniscus ‘s seen below that in the outer tube. The extent of this iepression depends upon the diameter, &c., of the capil- ary tube, and on the nature of its internal surface. As stated in June, 1879, when the capillary tube dips but rery slightly below the surface the liquid disappears at he same level in the capillary and external tube at the sritical temperature. Long contact of the liquid with the :apillary tube may also cause the depression to be absent ‘he first time of heating. (1.) The depression results from 1 surface action between the liquid and inner glass surface of the capillary tube. (2.) Surfaces exercise an appre- viable action in determining the position at which the :ondensation of liquid takes place in the external tube on -apid cooling. (3.) Near the critical temperature the sur. ace of a liquid (particularly in an external tube zo m.m.) ippears convex when really slightly concave. This is the esult of refra@ion. (4.) The black, ill-defined band which mmediately succeeds the disappearance of the liquid sur- ‘ace is a result of too rapid heating, and probably due to :he mixture of the liquid and its vapour when of nearly aqual density. Very slowly heated, the defined concave surface is gradually obliterated, and is last seen as a very fine and often waving line. Under these circumstances ihe disappearance-volume of the liquid is much greater than it is when rapidly heated. Rapidly cooled the liquids reappear at a lower temperature (about 2° C.) and smaller volume than that at which they become gases under the same conditions on heating. Mr. WINSTANLEY explained two new varieties of air ‘hermometers and a thermograph actuated by an air ther- nometer on the principle of his radiograph exhibited at he last meeting. The first thermometer consists of a :ube with terminal bulbs, and the left leg of much finer sore than the right. Mercury is in the right leg; sulphuric acid surmounted with air in the left. The apparatus is a >arometer to the air inside the left bulb and a thermo- meter to that outside. A similar combination of an air chermometer and an Aneroid barometer constitutes the second instrument. ‘The expansion or contraction of the air in the stem by external temperature expands or com- sresses a small aneroid chamber in the bulb. Mr. GEE and Mr. STROUD made a communication “On 1 Modification of Bunsen's Calometer,” which will be found n the Proceedings of the Society. The meeting then ad- ourned till the winter session commences. Prof. W. G. ApaMs in the Chair. Mr. C. V. Boys read a paper by Prof. Guthrie and him. self * On the Measurement of the Conductivity of Liquids by means of Magneto-Electric Induction.” ‘The liquid is suspended in a glass vessel by a fine iron wire inthe centre of a cylindrical ele&ro-magnet formed of two semi- circular parts. This electro-magnet is rotated at a velo- city not exceeding 3oco0 turns per minute, and the liquid being drawn round in the direction of rotation, the wire is subjected to torsion which, under correction for certain errors, is proportional tothe resistance of the liquid. The torsion is observed by means of a scale and microscope. The results plotted in a curve agree very closely with those of Kohirausch obtained by alternate currents, and Dr. Guthrie thinks that they are probably more correct and trustworthy than Kohlrausch’s, for the motion would seem to be superior, and the curve contains fewer eccentric points than his. Dr. GLADSTONE read a paper “On the Refraction Eguivalents of Isomeric Bodies,” in which he described the present state of the subject and his own contributions to it. He showed that the refra&ive power of bodies over light was of great importance to chemists, since it depended on their essential structure. | “Dr. Hueains described his latest results of star-spettra, and illustrated his remarks by photographic spectra taken by his improved method. From these it appears certain stars, such as Vega, gives a complete spectrum of hydro. gen. Others, more yellowish in colour, show a thinning of these lines, such as Sirius and Ursa Majoris. Others show the intrusion of more refrangible lines—for example, ArQurus, Aquila, and Virginius, while Capella gives a tomplex spe@rum like that of the sun. Dr. Huggins also showed a spectrum of the flame of a spirit-lamp, which present a strong group of lines at S, and he considered it to represent the light emitted by the molecules of water. He further observed that the spedrum offered a highly iensitive test of the presence of carbon. ‘Mr, LiveiNG exhibited a new fire-damp indicator, capable of dete®ing } per cent. of marsh-gas in air. It is based on the fa that an incandescent body shows more brilliantly in proportion to the amount of marsh-gas in the air, and consists of two fine platinum wires kept in- randescent by a magneto-eledric current sent through them in one circuit. One wire is excluded from the fire. Jamp; the other is exposed to it, and the relative inten. sities of the two glowing wires is compared by a photo- metric screen placed between them, and adjustible to a position between them at which the reflections of the wires on the screen are as equal in intensity. The posi- tion of the screen relatively to the wires is given by a scale, and measures the proportion of fire-damp in the air. The contrivance is more advantageous than the gafety lamp, which only indicates 2 per cent. of marsh- gas in the air. Dr. STONE explained a new vacuum shunt for induc. fion currents.devised by himself and Dr. Keiler. It con. iste of a mercury barometer tube with Torricellian The Distribution of Light in the Spectrum.—]. Macé and W. Nicati.—In order to measure the distribution »f luminous intensity in the spectrum it is necessary to take, 1s the starting point, a physiological fa, well defined, and independent of colour, They consider two quantities >f light as respectively equal when they, illuminating one ind the same colourless obje, placed at the same distance rom the same observer, enable him to see its details with he same distin@ness.—Comptes Rendus.

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fullscreen: Chemical news and Journal of physical science (Volume 42, 1880 (July - December))

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