There are also smaller spaces like four-em and five-em spaces (known as thin spaces) and hair spaces, but we don’t need to worry about them. In other words, the standard spacing was a thick space (one-third of an em) between words (the same as it is today), a little bit more than that (half an em) after semicolons or colons that were followed by a lowercase letter, two thick spaces after a colon followed by a capital, and the equivalent of three thick spaces between sentences. On a typewriter, there’s no such thing as a thin space, en space, or em space.