The Military uses of the Palantiri.

[Alfirin]

Originally Posted by Inziladun

I think
Conversely,the larger ones, such as the Stones of Amon Sûl and Osgiliath, lacked the fixed orientation, but were probably too large and heavy to be practically carried into a battle situation.
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I don't know about the Amon Sûl stone, but with the Osgilaith one there would be little question; as I recall the UT essay mentions that it is so large it takes four stong people to lift and carry it; not ideal for carrying into battle (though if you could mount it in a cart.....)