Of liquid collectors the representative is Lord Kelvin's water-dropping electrograph; while Benndorf's is the form of radium collector that has been most used.
But while gaseous products and even falling water are capable of modifying electrical conditions in their immediate neighbourhood, the " infection " produced by radium is more insidious, and other drawbacks present themselves in practice.
It requires a radium salt of high radioactivity to be at all comparable in effectiveness with a good water-dropper.
Unless the insulation is perfect, the potential recorded falls short of that at the spot where the radium is placed or the water jet breaks.
Having a number of fine holes, or having a fine jet under a considerable pressure, picks up the potential in about a tenth of the time required by the ordinary radium preparation protected by a glass tube.
These Figures Refer To The State Of The Wire Immediately After The Exposure; The Rate Of Decay Is Much More Rapid For The Radium Than For The Thorium Emanation.
About the beginning of the 10th century, however, the view was promulgated that the spontaneous production of helium from radium may be an instance of the transformation of one element into another.
Turning to the study of radioactivity, he noticed its association with the minerals which yield helium, and in support of the hypothesis that that gas is a disintegration-product of radium he proved in 1903 that it is continuously formed by the latter substance in quantities sufficiently great to be directly recognizable in the spectroscope.
An authority on precious stones, and especially the diamond, he succeeded in artificially making some minute specimens of the latter gem; and on the discovery of radium he was one of the first to take up the study of its properties, in particular inventing the spinthariscope, an instrument in which the effects of a trace of radium salt are manifested by the phosphorescence produced on a zinc sulphide screen.
Physics and Chemistry.-Bulletin des sciences physiques (1888); L'Eclairage electrique (1894); Le Radium (1904); Revue generale des sciences pures et appliquees (1890); Revue pratique de l'electriciti (1892).
Strutt found that salt from evaporated sea-water did not contain one-third of the quantity of radium present in the water of the town supply in Cambridge.
The striking discovery was, in 1903, made by the same investigators that the spontaneous luminosity of radium gives a spectrum of a kind never before obtained without the aid of powerful excitation, electrical or thermal.
At Jachymov (Joachimsthal), in North Bohemia, radium is produced.
The national debt amounted to some 40 billion crowns, against which the state itself possessed assets in the shape of forests, coal mines, the former domains of the Habsburgs, mineral, naphtha, radium and other sources of natural wealth, besides the State-owned railways.
Bordas, the blue colour of sapphire exposed to the action of radium changes to green and then to yellow.
Although he had previously published meritorious researches on piezoelectricity, the magnetic properties of bodies at different temperatures, and other topics, he was chiefly known for his work on radium carried out jointly with his wife, Marie Sklodowska, who was born at Warsaw on the 7th of November 1867.
Sir William Crookes has, however, changed a pale yellow diamond to a bluish-green colour by keeping it embedded in radium bromide for eleven weeks.
The phosphorescence produced by friction has been known since the time of Robert Boyle (1663); the diamond becomes luminous in a dark room after exposure to sunlight or in the presence of radium; and many stones phosphoresce beautifully (generally with a pale green light) when subjected to the electric discharge in a vacuum tube.
RADIUM (from Lat.
After removing the uranium, it was found that the bismuth separated with a very active substance - polonium; this element was afterwards isolated by Marckwald, and proved to be identical with his radiotellurium; that the barium could be separated with another active substance - radium; whilst a third fraction, composed mainly of the rare earths (thorium, &c.), yielded to Debierne another radioactive element - actinium, which proved to be identical with the emanium of Giesel.
There is more radium than any other radioactive element, but its excessive rarity may be gauged by the facts that Mme.
There is a mass of evidence to show that radium is to be regarded as an element, and in general its properties resemble those of the metals of the alkaline earths, more particularly barium.
To the bunsen flame a radium salt imparts an intense carmine-red colour (barium gives a green).
Radium itself emits three types of rays: (1) the a rays, which are regarded as positively charged helium atoms; these rays are stopped by a single sheet of paper; (2) the s rays, which are identified with the cathode rays, i.e.
In addition, radium evolves an "emanation" which is an extraordinarily inert gas, recalling the "inactive" gases of the atmosphere.
We thus see that radium is continually losing matter and energy as electricity; it is also losing energy as heat, for, as was observed by Curie and Laborde, the temperature of a radium salt is always a degree or two above that of the atmosphere, and they estimated that a gramme of pure radium would emit about 100 gramme-calories per hour.
Since that time active investigation into the action of radium on diseased tissues has been carried on, resulting in the establishment in Paris in 1906 of the "Laboratoire biologique du Radium."
The diseases to which the application has been hitherto confined are papillomata, lupus vulgaris, epithelial tumours, syphilitic ulcers, pigmentary naevi, angiomata, and pruritus and chronic itching of the skin; but the use of radium in therapeutics is still experimental.
Radium is analgesic and bactericidal in its action.
Szilard, Le Radium, 190q, 6, p. 233).
This research opened a way of approach to the phenomena of radioactivity, and the history of the steps by' hich P. Curie and Madame Curie were finally led to the discovery of radium is one of the most fascinating chapters in the history of science.
The study of radium and radioactivity led before long to the further remarkable knowledge that these so-called radioactive materials project into surrounding space particles or corpuscles, some of which are identical with those projected from the cathode in a high vacuum tube, together with others of a different nature.
Chem., 1893, 6, p. 89), by determining the equivalent of barium chloride and bromide to silver, obtained the value 137.44 For the relation of barium to radium, see Radioactivity.
Antimony is extracted at Milleschau near Tabor; uranium and radium near Joachimsthal; graphite near Krumau and Budweis; porcelain-earth near Carlsbad.
A modification in this proposition which may hereafter be accepted involves an extension of our ideas of temperature, and leads us to regard the interior heat of the heavenly bodies as due to a form of molecular activity similar to that of which radium affords so remarkable an instance.