Goofs

Anyone traveling in a balloon never feels the wind, or hears it, because they are advancing at the same speed. Wide shots depict this phenomenon, but in close-ups while aloft, both characters are shown affected by light gusts and the sound of the wind, scientifically inaccurate to the conditions of balloon travel.

In reality, they would have unfortunately suffered from hypoxia and become icecubes, given the commonly accepted international standard atmosphere (ISA) model.

Several characters seem to address the widowed Amelia as Miss Wren, which is her maiden name, instead of Mrs Rennes. However, since the French name Rennes is pronounced exactly the same as the English name Wren, they could very well be saying the correct name.

Amelia Wren pronounces "caelum certe" with hard C's. This is the current, "reconstructed Classical" pronunciation; however, in the 1860s the standard Latin pronunciation used would have been with soft C's.

Several characters address Amelia as Miss Wren which is her maiden name. No gentleman would do this especially in Victorian times. Amelia is a widow and should therefore be addressed by her late husband's name as Mrs. Rennes.

The supposedly wise old men of the scientific society maintain that rain is just something which happens at random, as though a rain cloud mysteriously pops into existence, drops its cargo of water, then just as mysteriously pops out again.

However, people who live by a clifftop have always known that a cloud can be seen coming from many hours away, sailing above a moving patch of sea roughened by raindrops.