Huygens disappoints - but should he?

In 1690, Christian Huygens wrote his last, great treatise. The Celestial Worlds Discover'd: Conjectures Concerning the Inhabitants, Plants, and Productions of the Worlds in the Planets. According to the history books it was admired by scientists, mathematicians, artists, musicians, and kings.

This extraordinary book (it says here), the first of its kind, gave credence to the idea that the Universe be populated with "...so many Suns, so many Earths ...And how must our Wonder and Admiration be increased when we consider the prodigious Distance and Multitude of the Stars." It would take nearly 300 years for us to recognize the truth in those words, and those words live on today. Though many of his conjectures were wrong, we are amazed at the inherent truth in Huygen's imagination. He was, perhaps, our first true traveller among the stars, and we are richer for it.

So much for the hagiography. The thing is, I read this book at the British Library today and was disappointed. He populates all the planets with animals and plants. OK. He says they need water. OK. He says water on Jupiter would freeze and on Venus would evaporate. OK we have a problem here. He then says that for this reason, on Jupiter there must be a special sort of frost-resistant water and on Venus another special sort of water that’s evaporation resistant. I mean what’s this guy on? Then he says that the inhabitants of the Moon would see the Earth revolving in the sky, and they would see countries that even we haven’t discovered yet. That’s nice, I like that. And always in the same place in the sky … huh? Is that right? Well, pass over that, and then that they would see the stars during the daytime because the Moon has no atmosphere (and it’s only our atmosphere that makes daylight when the sun is up, otherwise we would see the Sun against a black sky and see the stars in the daytime). That’s good, he’s got all that right. But stop! If there’s no atmosphere on the Moon, then all the inhabitants are dead! The man’s a fool!

Time for reflection. Reasons why the above is unfair. This book was published in 1690 (or 1698 according to the copies I've seen). 1687 is the date of Newton’s great book. So is it too soon to expect an understanding that the laws of physics are uniform throughout the universe (no special sorts of water) and that you need to breathe air to live?  Anyway, there is as it happens a special sort of water that’s liquid on Jupiter, it’s called methane and it may support life. So I’ve come round in a circle. Huygens is OK after all.