Albert Einstein is frequently quoted saying: "The wireless telegraph
is not difficult to
understand. The ordinary telegraph is like a very long cat. You pull
the
tail in New York, and it meows in Los Angeles. The wireless is the
same,
only without the cat." I have found variant forms of this, and no
attribution or date. I wish to cite this quote in its correct form
with attribution in a book I am co-authoring. Where did it come from
and did Einstein really say it?

No luck so far. Could it have been said in the context of a radio
interview in New York?

http://groups.google.com/groups?q=einstein+%22long+cat%22&start=30&hl=en&lr=&ie=UTF-8&oe=UTF&selm=37a887af.90244565%40news.zipworld.com.au&rnum=35

Hello Glenn,

Since I cannot find a definitive answer, I will post this as a
comment.

First, after going through the vast majority of links with Einstein
quotes, I would offer the following version as the most likely
"correct form" as it appears in most of the sites quoting Einstein:

"You see, wire telegraph is a kind of a very, very long cat. You pull
his tail in New York and his head is meowing in Los Angeles. Do you
understand this? And radio operates exactly the same way: you send
signals here, they receive them there. The only difference is that
there is no cat."

Now, given the syntax of the quote, this really sounds like he is
answering a question, as opposed to trying to describe something on
paper.  So, an interview response is the most probable source.  But
none of the sites I looked at offered any exact citation, nor can I
dig up any transcripts of radio interviews.

I can point you to two resources that may help you out, though.  The
first is the official Einstein archives, in Israel:
http://www.albert-einstein.org/.  The second is the author of "The
Expanded Quotable Einstein" (
http://pup.princeton.edu/titles/6908.html ), Alice Calaprice, who
seems to be somewhat of an authority on Einstein at Princeton.

I hope this helps.

For what it is worth, the quote appears in the same form in two
locations that I have found. Note that the last few words of this
version differ from those in the version you have.

Text: "The wireless telegraph is not difficult to understand. The
ordinary telegraph is like a very long cat. You pull the tail in New
York, and it meows in Los Angeles. The wireless is the same, only
without the cat." - Albert Einstein

Source: _Scientific American_ magazine, September 2002 issue,
"Einstein's Hot Time", by Steve Mirsky.
  http://www.sciam.com/article.cfm?articleID=0001AA08-864C-1D49-90FB809EC5880000

Source: Science Master April 2001 newsletter
  http://www.sciencemaster.com/activity/newsletter/april_news.html

Mirsky's article in Scientific American actually focuses on a similar
quote attributed to Einstein: "When a man sits with a pretty girl for
an hour, it seems like a minute. But let him sit on a hot stove for a
minute and it's longer than any hour. That's relativity." (Hence the
article's title.)

Even though the question has expired, for what it's worth, here's a
message I received today from The Albert Einsten Archives in 
Jerusalem concerning the "quote"...

"...Unfortunately, I could not find this quote in our documents. That
may not necessarily mean that Einstein never said something similar,
though a quote of this kind would probably have been included in (one
of) the various collections of Einstein quotes we are using for
references. I suspect, however, the quote not being an authentic
Einstein quote at all. Though in parts it may sound more or less
"Einsteinian", the conclusion reminds me too much of a joke than of
Einstein's sophisticated puns."

regards,

rico