Radio-active Substances

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Chemical News Office, 1904 - Chemistry - 94 pages
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Page 39 - Under these conditions, it is evident from the electrometer that the radium has a positive charge equal in magnitude to the negative charge of the former experiment.
Page 16 - The results of the investigation of radio-active minerals, announced in the preceding chapter, led M. Curie and myself to endeavour to extract a new radio-active body from pitchblende. Our method of procedure could only be based on radio-activity, as we know of no other property of the hypothetical substance. The following is the method pursued for a research based on radio-activity: — The radio-activity of a compound is determined, and a chemical decomposition of this compound is effected; the...
Page 94 - Thus the new method of investigating new chemical elements, established by M. Curie and myself, based upon radio-activity, is fully justified. I have investigated the law of absorption of polonium rays, and of the absorbable rays of radium, and have demonstrated that this law of absorption is peculiar and different from the known laws of other radiations. I have investigated the variation of activity of radium salts, the effect of solution and of heating, and the renewal of activity with time, after...
Page 14 - Radio-activity a general Phenomenon ? As I have said above, I made experiments to discover whether substances other than compounds of uranium and thorium were radio-active. I undertook this research with the idea that it was scarcely probable that radio-activity, considered as an atomic property, should belong to a certain kind of matter to the exclusion of all other. The determinations I made permit me to say that, for chemical elements actually considered as such, including the rarest and most...
Page 65 - Certain bodies, such as fluorite, become luminous when heated ; they are thermo-luminescent. Their luminosity disappears after some time, but the capacity of becoming luminous afresh through heat is restored to them by the action of a spark, and also by the action of radium. Radium can thus restore to these bodies their thermo-luminescent property.
Page 94 - ... character of the radio-activity of the compounds of uranium and thorium. I have conducted a research upon radio-active substances other than uranium and thorium. To this end I investigated a large number of substances by an accurate electrometric method, and I discovered that certain minerals possess activity which is not to be accounted for by their content of uranium and thorium. From this I concluded that these minerals must contain a radio-active body different from uranium and thorium, and...
Page 14 - ... radio-activity, considered as an atomic property, should belong to a certain kind of matter to the exclusion of all other. The determinations I made permit me to say that, for chemical elements actually considered as such, including the rarest and most hypothetical, the compounds I investigated were always at least 100 times less active in my apparatus than metallic uranium. The following is a summary of the substances experimented upon, either as the element or in combination : — 1. All the...
Page 27 - ... remains in the slightly aqueous alcoholic solution, and can thus be removed. M. Giesel, who, since the publication of our first researches, has been preparing radio-active bodies, recommends the separation of barium and radium by fractional crystallisation in water from a mixture of the bromides. I can testify that this method is advantageous, especially in the first stages of the fractionation. DETERMINATION OF THE ATOMIC WEIGHT OF...
Page 24 - PREPARATION OF THE PURE CHLORIDE OF RADIUM The method by which I extracted pure radium chloride from barium chloride containing radium consists in first subjecting the mixture of the chlorides to fractional crystallisation in pure water, then in water to which hydrochloric acid has been added. The difference in solubility of the two chlorides is thus made use of, that of radium being less soluble than that of barium. At the beginning of the fractionation, pure distilled water is used. The chloride...

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