Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: cathode rays - historical question



I've been reminded that Pais, in Inward Bound discusses the question in detail.

An interesting point that I learnt last night:

Crookes in 1879, from Maltese Cross and paddle wheel tubes proposed a
corpuscular view - "radiant matter"/"molecular torrents" but had in mind
molecules of residual gas that gained negative charged by colliding with
the cathode. Goldstein calculated the mean free path of gas molecules in a
tube of known residual pressure and showed that it was way shorter than the
rectilinear propagation distance of the cathode rays in the Maltese Cross
tube. So this rectilinear propagation was cited as evidence *against* the
particle model as it was in the 1880's.

Elementary textbooks generally say the opposite, assuming that
investigators were looking for signs of diffraction to confirm wave
behaviour. This has always struck me as odd since they presumably "knew"
that light was a wave and would not show signs of diffraction in similar
circumstances.

Mark



Mark Sylvester
UWCAd
Duino Trieste Italy