Plum Pudding

The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote.... Our future discoveries must be looked for in the sixth place of decimals.
- Albert. A. Michelson, speech at the dedication of Ryerson Physics Lab, U. of Chicago 1894

The following year, Roentgen discovered X-rays; a year later, in 1896, Becquerel discovered radioactivity; and J.J. Thomson electrified physics in 1897 when he announced that cathode "rays" were really beams of electrons or what he called "corpuscles."

Thomson knew as much as anyone about electricity and its conduction--that electricity could flow here and there like invisible water and it could even be tamed and put to use. The electron, named after the Greek word for amber, had even been proposed before but had remained safely ensconced in matter. Thomson disclosed it. Disrobed it. What the electron lost in privacy, it gained in primacy and notoriety. Alone and naked for the first time, the electron succumbed to further scrutiny--first its mass-to-charge ratio was measured by Thomson. Soon after, it was actually weighed by Millikan (ironically at the University of Chicago--see quote above). But the real shocker at the time was that atoms were divisible--they were not a-tomos. This destroyed a comfortable notion of integrity.

JJ Thomson. Note the photograph (second from right) which is an early X-ray of the hand of Frau Roentgen

Knowing that he could strip off little negative bits, but not having a working notion of the countervailing positive portion which was surely left behind, Thomson theorized that electrons were uniformly sprinkled in a positively-charged, amorphous medium. The model was dubbed Plum Pudding. And why not? Thompson went with what he knew.  He would have overreached any data to have proposed anything else. And so, for the interregnum roughly corresponding to the Edwardian era—until Ernest Rutherford undid it—the atomic model looked like this:

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Suggested reading: history of the electron

This story continues here: link

"Rutherford was an artist. All his experiments had style."

Ernest Rutherford (1871-1937)

Ernest Rutherford reminds me of Michael Faraday. Born in humble circumstances in faraway New Zealand, he travelled to the mother country to study physics. Like Faraday, equal opportunity earned him a place with the best of his day and this meant the Cavendish Laboratory at the University of Cambridge. Rutherford must have witnessed J.J. Thomson's discovery of the electron there in 1897 but there's no record of him taking part in that work. It didn't matter--he had enough in him for two careers in science and a Nobel Prize of his own. And one of Rutherford's great achievements was the accidental undoing of his mentor's plum-pudding model of the atom.

Rutherford's first independent work was the unravelling of radioactivity along with Fredrick Soddy.  More on this later. But first, I want to close a loop I opened a few posts ago by hinting that I had found an inconsistency. I was referring to Richard Rhodes' account of Rutherford receiving the 1908 Nobel Prize in Chemistry:

An eyewitness to the ceremonies said Rutherford looked ridiculously young--he was thirty-seven--and made the speech of the evening. He announced his recent confirmation, only briefly reported the month before, that the alpha particle was in fact helium. The confirming experiment was typically elegant. Rutherford had a glassblower make him a tube with extremely thin walls. He evacuated the glass tube and filled it with radon gas, a fertile source  of alpha particles. The tube was gas tight, but its thin walls allowed alpha particles to escape. Rutherford surrounded the radon tube with another gas tube, pumped out the air between the two tubes and sealed off the space. 'After some days,' he told his Stockholm audience triumphantly, 'a bright spectrum of helium was observed in the outer vessel.' Rutherford's experiments still stun with their simplicity. 'In this Rutherford was an artist,' says a former student. 'All his experiments had style.' 

~Richard Rhodes in "The Making Of The Atomic Bomb"

Rhodes' book is a favorite of mine and I've read it a couple times. But Rhodes makes no mention of Soddy and Ramsey's proof five years earlier that the alpha particle was helium. According to Wikipedia:

In 1903, with Sir William Ramsay at University College London, Soddy verified that the decay of radium produced alpha particles composed of positively charged nuclei of helium. In the experiment a sample of radium was enclosed in a thin walled glass envelope sited within an evacuated glass bulb. Alpha particles could pass through the thin glass wall but were contained within the surrounding glass envelope. After leaving the experiment running for a long period of time a spectral analysis of the contents of the former evacuated space revealed the presence of helium. This element had recently been discovered in the solar spectrum by Bunsen and Kirchoff.* link

This account essentially parallels the elegant (but later) experiment announced in 1908 by Rutherford and described by Rhodes with the exception of radium instead of radon as the source of alpha particles. However, my review of the 1903 Ramsey & Soddy paper cited by the Wiki actually describes a much different and less elegant experiment. link
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*Also, Bunsen and Kirchoff didn't find helium in the solar spectrum--Lockyer did: link

What's Love Got To Do With AGW?

Sissy Willis points to a very important paper published in Nature. I haven't seen it yet, but I will (Nature papers are behind a pay wall).  Breitbart News is on the case.  Don't expect the MSM to pick this up anytime soon. In a nutshell, the paper contributes the news that CO₂ is a minor contributor to AGW, i.e., there are multiple hypotheses to explain earth's increasing temperatures. The real news here is the venue of publication, the venerable Nature.  Will America's leading scientific journal, Science, also allow dissent? If both mainstream science publications pick this up, then perhaps there finally can be a grown up discussion on "what to do" about warming if anything. Meanwhile, I applaud Nature for publishing this. Scientific integrity ultimately depends on such decisions.

As for my title, a recent unrelated turn of events led me to an astonishingly prescient paper by T.C. Chamberlin published in 1897. Chamberlin was president of the University of Wisconsin from 1887 to 1892 (there is a building named after him there, IIRC). Chamberlin wrote a highly influential paper called The Method of Multiple Working Hypotheses which I reproduce in part below. The snippet is lengthy (but rich) and offers almost a psychological analysis of how good science can fail:

Love was long since represented as blind, and what is true in the personal realm is measurably true in the intellectual realm. Important as the intellectual affections are as stimuli and as rewards, they are nervertheless dangerous factors, which menace the integrity of the intellectual processes. The moment one has offered an original explanation for a phenomenon which seems satisfactory, that moment affection for his intellectual child springs into existence; and as the explanation grows into a definite theory his parental affections cluster about his intellectual offspring and it grows more and more dear to him, so that, while he holds it seemingly tentative, it is still lovingly tentative, and not impartially tentative. So soon as this parental affection takes possession of the mind, there is the rapid passage to the adoption of theory. There is an unconscious selection and magnifying of the phenomenon that fall into harmony with theory and support it, and an unconscious neglect of those that fail of coincidence. The mind lingers with pleasure upon the facts that fall happily into the embrace of the theory, and feels a natural coldness toward those that seem refractory. Instinctively there is a special searching-out phenomenon that support it, for the mind is led by desires. There springs up, also, an unconscious pressing of the theory to make it fit the facts and a pressing of the facts to make them fit the theory. When these biasing tendencies set in, the mind rapidly degenerates into the partiality of paternalism. The search for facts, the observation of phenomena and their interpretation are all dominated by affection for a favored theory until it appears to its author or its advocate to have been overwhelmingly established. The theory then rapidly rises to the ruling position, and investigations, observation, and interpretation are controlled and directed by it. From unduly favored child, it readily becomes master, and leads its author whithersoever it will. The subsequent history of that mind in respect to that theme is but the progressive dominance of a ruling idea.

Briefly summed up, the evolution is this: a premature explanation passes into tentative theory, then into an adopted theory, and then into ruling theory. 

~ T.C. Chamberlin, The Journal of Geology, 1897, 5: 837-848.  Link.

Related thoughts here