Some part, however, seems to be derived from Thorium, And H.
Bumstead (60) Finds That With Longer Exposure Of The Wire The Relative Importance Of The Thorium Emanation Increases.
With Three Hours' Exposure He Found The Thorium Emanation Only From 3 To 5% Of The Whole, But With 12 Hours' Exposure The Percentage Of Thorium Emanation Rose To About 15.
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.
Helium is relatively abundant in many minerals, all of which are radioactive, and contain uranium or thorium as important constituents.
(For the significance of this fact see Radioactivity.) The richest known source is thorianite, which consists mainly of thorium oxide, and contains 9.5 cc. of helium per gram.
Monazite, a phosphate of thorium and other rare earths, contains on the average about i cc. per gram.
In two cases, however, it has been found in the absence of appreciable quantities of uranium and thorium compounds, namely in beryl, and in sylvine (potassium chloride).
Within these limits are to be found most of the minerals known - gold, silver, quicksilver, copper, lead, zinc, iron, manganese, wolfram, bismuth, thorium, vanadium; mica, coal, &c. On or near the coast are coal, salt, sulphur, borax, nitrates and petroleum.
In its chemical affinities zirconium resembles titanium, cerium and thorium; it occurs in company with these elements, and is tetravalent in its more important salts.
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.
Thorium and lead.
Thorium has proved to be very widely, although extremely sparingly, distributed: pyrochlor, orangite, monazite, euxenite, gadolonite, orthite, and in fact most of the rare minerals of this type contain it (see B.
The extraction of thorium salts from these minerals is a matter of much tedium.
Metallic thorium is obtained by heating potassium thorium chloride or the tetrachloride with sodium '(see W.
In its salts, thorium is tetravalent, and in the periodic classification it occurs in the same sub-group as titanium, cerium and zirconium.
Thorium dioxide or thoria, Th02, is the most important compound, being manufactured commercially in comparatively large quantities from monazite sands, with a view to its utilization for gas mantles (see Lighting, Gas).
Thorium fluoride, ThF 4, is obtained as a heavy white insoluble powder by dissolving the hydrate in hydrofluoric acid and evaporating.
By precipitating a thorium salt with a fluoride, a gelatinous hydrate, ThF 4.4H 2 O, is obtained.
Acid potassium fluoride precipitates K2ThF6 4ThF4 H20 from a solution of thorium chloride.
Thorium chloride, ThC1 4, is obtained as white shining crystals by heating a mixture of carbon and thoria in a current of chlorine.
He concluded that the first contained the chloride of berzelium, having an atomic weight of 212, the second contained thorium chloride, and the third the chloride of carolinium, having an atomic weight of 255.6.
Thorium chloride readily deliquesces on exposure and forms double salts with alkaline chlorides.
Thorium sulphate, Th(S04)2, is obtained by dissolving the oxide in sulphuric acid.
Thorium sulphate forms double salts with the alkaline sulphates.
Thorium nitrate, Th(NO 3) 4.12H 2 O, forms white deliquescent tables very soluble in water.
Thorium sulphide, ThS2, is obtained by burning the metal in sulphur.
For the so-called "disintegration of the thorium atom" and the relation of this element to the general subject of radio-active emanations, see Radio-Activity.
A number of salts of thorium have been prepared for therapeutic use, including the hydroxide, nitrate, salicylate, oleate and lactate.
Inhalations of thorium emanations produced from thorium nitrate through a wash-bottle inhaler are said to have a bactericidal action in diseases of the lungs.
The phosphorescence of the sulphide obtained by heating the thiosulphate is much increased by adding uranium, bismuth, or thorium before ignition pr.