When Mary and Tad Lincoln traveled to New York to escape the Washington heat in September 1863, the president missed her.
He wrote this to her at her Fifth Avenue hotel:
“The air is so clear and cool, and apparently healthy, that I would be glad for you to come. Nothing very particular, but I would be glad to see you and Tad. A. Lincoln”
Source: Abraham Lincoln: The Writer, edited by Harold Holzer