The subject of the experiments is Angelica who is described as a werefox, having many of the characteristics of a fox most notably being covered in fur. Through repeated attempts to go higher we discover that the wealthy gent has discovered that Angelica becomes more alert the thinner and colder the air gets as the balloon gains altitude.
Steam punk is always fun when it's done right and keeps to the engineering knowledge of the time. This story was fun.
The author's website is HERE
His bibliography is HERE
The story was originally published in Analog September 2010.