Physicist

Jean-Jacques Ampère, a successful merchant, was an admirer of the philosophy of Jean-Jacques Rousseau, whose theories of education (as outlined in his treatise Émile) were the basis of Ampère's education. Rousseau believed that young boys should avoid formal schooling and pursue instead a "direct education from nature." Ampère's father actualized this ideal by allowing his son to educate himself within the walls of his well-stocked library.

In 1914, Fermi, who used to often meet with his father in front of the office after work, met a colleague of his father called Adolfo Amidei, who would walk part of the way home with Alberto. Enrico had learned that Adolfo was interested in mathematics and physics and took the opportunity to ask Adolfo a question about geometry. Adolfo understood that the young Fermi was referring to projective geometry and then proceeded to give him a book on the subject written by Theodor Reye. Two months later, Fermi returned the book, having solved all the problems proposed at the end of the book, some of which Adolfo considered difficult. Upon verifying this, Adolfo felt that Fermi was "a prodigy, at least with respect to geometry", and further mentored the boy, providing him with more books on physics and mathematics. Adolfo noted that Fermi had a very good memory and thus could return the books after having read them because he could remember their content very well.

Just before he left Cambridge for Montreal in 1898, Rutherford conducted a simple, systematic experiment to study the absorption of rays from uranium. [...] In 1901 he determined that Becquerel's rays are indeed electromagnetic rays. He called them γ (gamma) rays.

Some minerals containing uranium and thorium (pitchblende, chalcolite, uranite) are very active from the point of view of the emission of Becquerel rays.

We have tried this experiment with LiC1 and observed the resonance peaks of Li and Cl. The effects are very striking and the resonances sharp (Fig. 1). A full account of this experiment, together with the values of the nuclear moments, will be published when the homogeneous field is recalibrated.

In two letters to this journal, we reported briefly on a new precision method of measuring nuclear moment, and on some results. In this paper we shall give a more detailed account of the method, apparatus and results.

Some minerals containing uranium and thorium (pitchblende, chalcolite, uranite) are very active from the point of view of the emission of Becquerel rays. In a previous work, one of us showed that their activity is even greater than that of uranium and thorium, and expressed the opinion that this effect was due to some other very active substance contained in small quantities in these minerals.

The study of compounds of uranium and thorium had shown, in fact, that the property of emitting rays which make air conductive and which act on photographic plates is a specific property of uranium and thorium which is found in all compounds of these metals, all the more weakened as the proportion of active metal in the compound is itself lower. The physical state of the substances seems to have a completely secondary importance. Various experiments have shown that the state of mixture of the substances seems to act only by varying the proportion of active bodies and the absorption produced by the inert substances. Certain causes (such as the presence of impurities) which act so powerfully on phosphorescence or fluorescence are therefore here completely without action. It therefore becomes very probable that if certain minerals are more active than uranium and thorium, it is because they contain a substance more active than these metals.

We have sought to isolate this substance in pitchblende, and experience has confirmed the above predictions.

Our chemical research has been constantly guided by the control of the radiant activity of the products separated at each operation. Each product is placed on one of the plates of a condenser, and the conductivity acquired by the air is measured using an electrometer and a piezoelectric quartz, as in the work cited above. We thus have not only an indication but a number which accounts for the richness of the product in active substance.

By carrying out these various operations, we obtain increasingly active products. Finally, we obtained a substance whose activity is about 400 times greater than that of uranium.

We have sought, among the bodies currently known, to see if there are any active ones. We have examined compounds of almost all simple bodies; thanks to the great kindness of several chemists, we have had samples of the rarest substances. Uranium and thorium are the only ones clearly active, tantalum is perhaps very weakly so.

We therefore believe that the substance that we have removed from the pitchblende contains a metal not yet reported, close to bismuth by its analytical properties. If the existence of this new metal is confirmed, we propose to call it polonium, from the name of the country of origin of one of us.

Mr. Demarçay was kind enough to examine the spectrum of the body that we are studying. He was unable to distinguish any characteristic line apart from those due to impurities. This fact does not support the idea of ​​the existence of a new metal. However, Mr. Demarçay pointed out to us that uranium, thorium and tantalum offer particular spectra, formed of innumerable lines, very fine, difficult to perceive.

Allow us to note that if the existence of a new element is confirmed, this discovery will be uniquely attributable to the new method of detection that Becquerel rays provide.

Two of us have shown that by purely chemical procedures it is possible to extract from pitchblende a strongly radio-active substance. This substance is related to bismuth by its analytical properties. We have expressed the opinion that perhaps the pitchblende contained a new element, for which we have proposed the name of polonium.

The investigations which we are following at present are in agreement with the first results we obtained, but in the course of these investigations we have come upon a second, strongly radio-active substance, entirely different from the first in its chemical properties. Specifically, polonium is precipitated from acid solution by hydrogen sulfide; its salts are soluble in acids and water precipitates them from solution; polonium is completely precipitated by ammonia.

The new radio-active substance which we have just found has all the chemical appearance of nearly pure barium: it is not precipitated either by hydrogen sulfide or by ammonium sulfide, nor by ammonia; its sulfate is insoluble in water and in acids; its carbonate is insoluble in water; its chloride, very soluble in water, is insoluble in concentrated hydrochloric acid and in alcohol. Finally this substance gives the easily recognized spectrum of barium.

We believe nevertheless that this substance, although constituted in its major part by barium, contains in addition a new element which gives it its radio-activity, and which, in addition, is closely related to barium in its chemical properties.

M. Demarçay has consented to examine the spectrum of our substance with a kindness which we cannot acknowledge too much. The results of his examinations are given in a special Note at the end of ours. Demarçay has found one line in the spectrum which does not seem due to any known element. This line, hardly visible with the chloride 60 times more active than uranium, has become prominent with the chloride enriched by fractionation to an activity 900 times that of uranium. The intensity of this line increases, then, at the same time as the radio-activity; that, we think, is a very serious reason for attributing it to the radio-active part of our substance.

The various reasons which we have enumerated lead us to believe that the new radio-active substance contains a new element to which we propose to give the name of radium.

We have measured the atomic weight of our active barium, determining the chlorine in its anhydrous chloride. We have found numbers which differ very little from those obtained in parallel measurements on inactive barium chloride; the numbers for the active barium are always a little larger, but the difference is of the order of magnitude of the experimental errors.

The new radio-active substance certainly includes a very large portion of barium; in spite of that, the radio-activity is considerable. The radio-activity of radium then must be enormous.

Uranium, thorium, polonium, radium, and their compounds make the air a conductor of electricity and act photographically on sensitive plates. In these respects, polonium and radium are considerably more active than uranium and thorium. On photographic plates one obtains good impressions with radium and polonium in a half-minute's exposure; several hours are needed to obtain the same result with uranium and thorium.

The rays emitted by the components of polonium and radium make barium platinocyanide fluorescent; their action in this regard is analogous to that of the Röntgen rays, but considerably weaker. To perform the experiment, one lays over the active substance a very thin aluminum foil on which is spread a thin layer of barium platinocyanide; in the darkness the platinocyanide appears faintly luminous above the active substance.

In this manner a source of light is obtained, which is very feeble to tell the truth, but which operates without a source of energy. Here is at least an apparent contradiction to Carnot's Principle.

Uranium and thorium give no light under these conditions, their action being probably too weak.

If we are honest - and scientists have to be - we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can't for the life of me see how the postulate of an Almighty God helps us in any way. What I do see is that this assumption leads to such unproductive questions as why God allows so much misery and injustice, the exploitation of the poor by the rich and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly God rewards - in heaven if not on earth - all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that God is a mere product of the human imagination is branded as the worst of all mortal sins.