[ATM] how many errors can you spot in this passage on Foucault?

[Anthony Stillman]

Guy asked:
>How many factual and conceptual errors...


> Foucault's great discovery in the area of...

Great here implies greatest.  It wasn’t his greatest.  That would be the foucault test.  And that wasn’t really his original notion either, more an advancement.  Also silvering wasn’t his discovery, he was first to apply Liedig’s process to a telescope mirror.  (2)


>...used bulky, heavy mirrors.  ...limited...collapse

Bulky implies a difficult to handle shape.  A disk is a disk.  Heavy, yes bronze is 3.7 times denser than glass.  That's not so much that a large disk of it would collapse a properly built telescope.  (2)


> Foucault inaugurated a new method...

Inaugurated, well the implication is correct, but it’s a poor choice of word.  (0)


> ....rather than...that was typically...

Foucault did not inaugurate the tin amalgam process, so that’s correct.  Typically.  Technically correct but its not a strong enough word as effectively all hand and wall mirrors at this time were tin-mercury backed glass.  (0)


>...lighter...better...as evidenced...a century and a half...

Yes, yes, no, and yes, if it was written in 2006.  (1)


So I count five mistakes.  About half right, about half wrong. As good as any high school text or any show I’ve seen on the discovery channel.


Anthony

"Don't get it right, just get it written" - Thurber


"Foucault's great discovery in the area of astronomical instrumentation was a method of silvering the mirrors for reflecting telescopes. Reflecting telescopes that had been made up to that time used bulky, heavy mirrors. This limited the potential size of these telescopes because the weight of the mirror could collapse the telescope. Foucault inaugurated a new method of applying a layer of silver directly to the front of the telescope's mirror, rather than a mercury amalgam that was typically applied to the back of the mirror. Foucault's telescopes built this way were lighter and of better light-gathering quality than earlier telescopes, as evidenced by their use today, a century and a half after his time."