[wp-hackers] Minor WordPress in a subdirectory problem

[onlyunusedname]

I'm wondering if anyone can help me from making a careless .htaccess
mistake.

My WordPress Address (URL) is:  http://mydomain.com/wordpress

My Site Address (URL) is:  http://mydomian.com

Going to http://mydomain.com/wordpress/some-permalink successfully
redirects to http://mydomain.com/some-permalink.  But going simply to
http://mydomain.com/wordpress gives a 404.

What is the wisest/safest way to get rid of this 404?

This is the rewrite rule from the .htaccess in the
http://mydomain.com/wordpress/ subdir:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /wordpress/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]
</IfModule>

Thanks.