user3456: In Milan Vidmar's book Goldene Schachzeiten he writes that the brilliant Paul Morphy was known to be an extraordinarily slow player, who would probably have had a hard life if time control were part of the chess battle.
I was shocked to read this because earlier I had always read that Morphy was an exceptionally fast player. Can anyone explain this controversy with access to reliable sources?

user8453: This 1860 book seems to have anecdotal evidence on the "fast" side of the argument: 
"Mr Morphy is a most fascinating player for those looking on, and there is always a crowd around his board whenever he is en lutte with an opponent. His attention is not by any means riveted on the game and he makes his moves with a speed approaching rapidity."
"Thus says Lowenthal in the Era:
We have great pleasure in announcing that Mr Morphy has arrived in London and has met with a most enthusiastic reception from the members of the St George's Club, where he paid a visit last Wednesday and played several excellent games. The prompt visit of this great player to England betokens his great anxiety to give the players of Europe an opportunity of encountering him. His powers as a Chess player have not in any degree been exaggerated. The quickness with which he forms and carries out his combinations is truly surprising. He possesses also another important quality, that of perfect coolness and self possession." 

user9419: My item here does not "explain the controversy", but for a contemporary tournament comment concerning Morphy, see top of page 90 here: https://archive.org/details/bookoffirstameri00fisk
From the First American Chess Congress book, quoting an article in The Chess Monthly:

Mr. Morphy is rapid in his moves and quick in his combinations, his
  time on any move never having reached a quarter of an hour; Mr.
  Paulsen is exceedingly slow, some of his moves having occupied more
  than an hour and several in succession having exceeded thirty minutes.

On page 246 and 248, specific listings of moves longer than 5 minutes for two of the Morphy-Paulsen games are given, and a similar comment on page 255.

3456: <p>In Milan Vidmar's book Goldene Schachzeiten he writes that the brilliant Paul Morphy was known to be an extraordinarily slow player, who would probably have had a hard life if time control were part of the chess battle.</p>

<p>I was shocked to read this because earlier I had always read that Morphy was an exceptionally fast player. Can anyone explain this controversy with access to reliable sources?</p>
 8453: <p><a href="https://books.google.co.uk/books?id=51ZeAAAAcAAJ&amp;dq=paul%20morphy%20move%20speed&amp;pg=PA19#v=onepage&amp;q=paul%20morphy%20move%20speed&amp;f=false" rel="nofollow">This 1860 book</a> seems to have anecdotal evidence on the "fast" side of the argument: </p>

<p>"Mr Morphy is a most fascinating player for those looking on, and there is always a crowd around his board whenever he is <em>en lutte</em> with an opponent. His attention is not by any means riveted on the game and he makes his moves with a speed approaching rapidity."</p>

<p>"Thus says Lowenthal in the Era:
We have great pleasure in announcing that Mr Morphy has arrived in London and has met with a most enthusiastic reception from the members of the St George's Club, where he paid a visit last Wednesday and played several excellent games. The prompt visit of this great player to England betokens his great anxiety to give the players of Europe an opportunity of encountering him. His powers as a Chess player have not in any degree been exaggerated. The quickness with which he forms and carries out his combinations is truly surprising. He possesses also another important quality, that of perfect coolness and self possession." </p>
 9419: <p>My item here does not "explain the controversy", but for a contemporary tournament comment concerning Morphy, see top of page 90 here: <a href="https://archive.org/details/bookoffirstameri00fisk" rel="nofollow">https://archive.org/details/bookoffirstameri00fisk</a></p>

<p>From the First American Chess Congress book, quoting an article in The Chess Monthly:</p>

<blockquote>
  <p>Mr. Morphy is rapid in his moves and quick in his combinations, his
  time on any move never having reached a quarter of an hour; Mr.
  Paulsen is exceedingly slow, some of his moves having occupied more
  than an hour and several in succession having exceeded thirty minutes.</p>
</blockquote>

<p>On page 246 and 248, specific listings of moves longer than 5 minutes for two of the Morphy-Paulsen games are given, and a similar comment on page 255.</p>
