I think it is safe to reveal this now, but I served as a Union spy during the Civil War.
Something you might have suspected since I have spoken freely of my work for the Underground, but not all my work was underground. Sometimes it was 500 feet up in the air!
How did I accomplish that marvelous feat, you ask? By volunteering as an Aeronaut.
But how did this come about? My work for the Underground had become well known. My eyes and my color made spying easy. Then I gained a reputation with my unusually stout parasol, made by Momma. (It's too short to function well as a parasol but it's dandy as a self-defense weapon!)
I also trained myself as a detective and became proficient with a magnifying glass. (I became interested in its use after reading future Sherlock Holmes books.)
So after reading about the formation of the Union Army Balloon Corps I raced over to HQ to volunteer my services.
At first I was mocked and ridiculed ("A girl! In the Army!!"), but I persevered and eventually won them over after demonstrating my varied and unique skills.
So I was trained in the use of a telescope (which I admit was hard with my eyes and I still prefer my binoculars) and my very own aether pistol! Don't worry, the pistol was permanently set on "Stun."
The Balloon Corps and I served the Union Army from October 1861 until the summer of 1863, when it was disbanded. I got to participate in four major battles though: Bull Run, Yorktown, Fair Oaks and Vicksburg.
Now you might be wondering, how did I manage all that when I didn't reach Philadelphia until 1864? Did you forget my TARDIS?
But what else could I possibly do when I belatedly read about Thaddeus S. C. Lowe, who met with U.S. President Abraham Lincoln on July 11, 1861, and proposed a demonstration with his own balloon, the Enterprise.
The Enterprise, really! How could I resist that!