Context: My theory book is elaborating on some rules for melodic motion to be applied to the soprano voice when Writing in Four Parts.
In the screenshot below, I'm trying to digest the quote:
Two leaps of 4ths are usually poor, but arpeggiation of a dominant 7th can be effective.
Question: Are these two statements intended to be read in contrast to one another? I'm trying to imagine a scenario where a dominant 7th chord could be arpeggiated by two consecutive leaps of a 4th, but can't see it happening.
Maybe these are simply two independent rules which are joined with the word "but"? I'm just seeking clarification on which interpretation is correct.