Something Better than a Vacuum Against Which to React

A reader asks: A few years ago, you posted a link to an article talking about early speculations into the impossibility of space travel (something about how, in the vacuum of space, there will be no air to react against or some such). I've tried to locate it, and seem to have been unable to. Do you recall what it was? Thanks!

A: Yes. Here is the article I wrote: http://johncwright.livejournal.com/2008/07/16/ Full text is below.

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I heard this story on Paul Harvey, and was so bemused, th...