|Reginald Fessenden electromagnetism|
- William Crookes spilled a little radium bromide
- on a screen coated with zinc sulfide.
- He noted under a microscope discrete scintillations—
- fluorescence from alpha particles emanating from the radium.
- Today the device he invented, the spinthariscope,
- is a novelty for viewing nuclear disintegrations.
- In its day it was wildly popular and led to the development
- of the Geiger counter and Rutherford’s model of the atom.
- Today instead of radium bromide, which is dangerous,
- spinthariscopes use americium, but the scintillations
- are objectively the same. Then, they didn’t know how dangerous
- it was. They thought it was good for you, even fun,
- not only that it made the hands of your Timex visible in the dark,
- but also that it could cure eczema and psoriasis. If they had known,
- subjectively, there could have been more to it.
- Suppose we could reconstruct
- a person’s past visual experiences
- by examining his retinas and brain.
- If so we could project these images
- on a tiny screen visible through a small lens.
- We could call them ghosts, and the Greek
- for ghost is fántasma. The only trouble is
- even though we know those images
- are in there, we cannot reconstruct them.
- If you start to see people who have passed away,
- you may be suffering from a form of dementia.
- This actually happened to someone I loved.