Get out the microscope, because we’re going through this poem line-by-line.
Lines 17-20
Then from 5,000 throats and more there rose a lusty yell;
It rumbled through the valley, it rattled in the dell;
It knocked upon the mountain and recoiled upon the flat,
For Casey, mighty Casey, was advancing to the bat.
- Here's the short version: the crowd cheered super-loud because Casey was coming to home plate (the place where the batter stands to hit).
- Those "5,000 throats" belong to the spectators. Using a part of something to represent the whole (like throats to represent whole people) is what's called in the poetry biz synecdoche.
- A few fans might have left (see stanza 2) but there's still a healthy crowd on hand and they are making quite a racket. It's a "lusty yell." No—it's not that kind of lusty. In this context, "lusty" just means strong and enthusiastic.
- How loud was it? Well, the sound of that cheering crowd was so loud that it echoed "through the valley."
- What's a "dell," you ask? A dell is basically another, more literary, term for a small valley. Remember the "Farmer in the Dell" from your younger years? It's like that. Dell is just a little more poetic-sounding than valley.
- In addition to all that valley-echoing, the sound also echoed through "the mountains" and "the flat." It reached near and far, the highlands, the lowlands, and everywhere in between—as we said before: super-loud.
- You might have noticed that those descriptive words—"rumbled," "rattled," and "recoiled"—all start with R. Those repeated initial sounds are known as alliteration. This repetition makes the R sound more intense, builds it up, mirroring the way the crowd noise is building. (Check out "Sound Check" for more on this technique.)
- To recap: Casey is coming to the plate. There are two outs, and there are two runners on base. Casey has a chance to win the game for the home team (if he can make it around the bases and back to home plate) and those Mudville fans are going wild.