He served as a Major in the 58th Regiment of New York Volunteers during the Civil War, acting also as a correspondant for Frank Leslies' Illustrated Newspaper.

<6 games were Chess variants. So they were experimenting.>

Not exactly. Those "variants" were Morphy giving odds.

<chanco>
Here is an interesting piece from the "Chess monthly: an American chess serial" Volume 3 (1859) (pp 294-295)

"Morphy and Lichtenhein

We have received a note from Mr Theodore Lichtenhein, protesting against the publication of a game in the August number of this magazine purporting to be played between him and Morphy, and stating that several Evans Gambits played by him were not games but analyses. In support of this assertion he alleges the fact that he took back several moves, which he would not have done had he supoposed them to be games.

Mr Morphy replies that he certainly entertained the idea that the contests were actual games and that there was no re-consideration of moves on his part. They were mostly played in the presence of witnesses who also declare that they regarded the combats as real battles. The score, at odds of the Knight, according to Mr Lichtenhein's view of the matter stands

Morphy 0 Lichtenhein 3 Draw 1

but Mr Morphy makes it

Morphy 6 Lichtenhein 4 Draw 1

Thanks, amazing. One of the odder zugzwangs I've ever seen. So...L & S probably made it up, like the Immortal Game.