One thing I noticed a while back in old newspapers was that the words “today” and “tomorrow” used to be hyphenated as “to-day” and “to-morrow”. I have long wondered: when did the usage change?
My wife suggested that I try a more systematic search and, for the Toronto Daily Star at least, this is possible: they had a daily weather report at the bottom of page one that always included the word “today” or “to-day”.
What I discovered was that the usage change in the Daily Star happened gradually between May and June of 1938. Here’s the weather forecast for May 14, 1938, which uses “to-day”:

The weather report for May 28 uses both spellings:

By June 13, the new spelling was in use throughout the weather report:

This is not conclusive evidence, of course, since the weather was only one feature that appeared in the paper, and the Daily Star’s usage might not be the same as usage elsewhere. I haven’t been able to figure out how to systematically search the Toronto Globe / Globe and Mail’s archive yet – from what I’ve seen, it started using “today” earlier. If I can find any definite information, I will post it here.