Google searching

In doing searches on Google, I have noticed that some texts, which appear to be searchable at one time, cease being searchable at a later time, even though they still exist on the same website.

For example, the text below is part of an article that seems to have gone the way of the Cheshire cat, and is most directly related to a complaint that BT cotton was ineffective against weevils in India:

To evaluate the effectiveness of the BT cotton, one
might want to know "how many" weevils were present and
"how much" cotton was present. A Civil War analogy is
useful. On December 13, 1862, Union commander Burnside
failed to take Marye's Heights at Fredericksburg. On
May 3, 1863, Union commander Sedgwick took the same
Marye's Heights. The different results arise from the
different relative numbers of Union and Confederate
troops on the two dates. The dramatic action of the
first date inspired Robert E. Lee to note: It is well
that war is so terrible: we would grow too fond of it!
[which quote might be that attributed to Napolean by
General Norman Schwarzkopf on Meet the Press, Feb. 9,
2003. http://www.msnbc.com/news/870638.asp.]
Sometimes, however, a nose count is not appropriate.
No matter how many microwave photons one has, one will
never ionize an atom, much like no matter how many
pennies one has, one will not get a candy bar from a
machine that only takes quarters.

[The last sentence is related to earlier discussion of Einstein and the photoelectric effect. The energy of the quantum, rather than the number of quanta, dictates whether certain chemistry will occur. One can have intense microwave radiation, but be unable to ionize an atom.]

Separately, I noticed that LEXIS deleted a certain article from the New York Times that once was available on LEXIS.

Although the "paper" copies of both these articles exist, the likelihood that they will be found by people doing searches is dramatically diminished when they cease to be electronically searchable.

[Also:
www.iptoday.com/march03/ebert3.pdf ]