This started as a conversation in comments with
danabren, but it seems to be worth moving into a post of its own.
I'm not quite sure whether the knit 1902 vest I'm making is supposed to be a layer next to the skin or a layer for extra warmth over the corset. I went into this project thinking it was meant to be a layer next to the skin. Now I'm not so sure. I'm also not quite sure whether the openwork across the bust is supposed to be threaded with ribbons or left open. If the latter, it seems it indicate that this goes over other garments because otherwise it's just mesh across the bust, which would not be pleasant under a corset. If the former, then maybe it does go next to the skin. But I know there were knitted garments that were worn next to the skin and were basically a long tank top like this is. Mostly I've seen those called "undervests." Do "undervests" go under the corset and "vests" go over it? Does the word "vest" indicate that it's a warmth layer? Or are the two words really interchangeable?
The pattern calls for silk, which would make you think it wasn't to be washed much and therefore not a layer next to the skin, but there were "washing silk" fabrics in the period, which were meant to be washed. I also think I've run into silk knit undervests and/or union suits somewhere, but I couldn't swear to that. If it's for warmth, I would actually think it would go on over the corset since most warmth comes from trapping air, and a corset would seem to squish more air out if it were underneath.

The pattern calls for "2-1/2 yards of pink satin ribbon about one inch in width, and 2-1/2 yards of very narrow pink satin ribbon to run in the neck." Then "Run ribbons through holes and tie in pretty bows in front." That's all it has to say about the ribbon. In the figure there's a row around the neck filled with white, and all the rows above it aren't. Presumably that's where you're running in the very narrow ribbon. So far, so good. Then in the openwork below, it's filled with white. If you run a 1" ribbon through the spaces there, you'd have to fold it in half along the width. There are nine rows so you'd be able to have about 10" of ribbon per row, which isn't enough to fill the whole mesh. So maybe the 2.5yd is just a ball-park. But then what about the matching mesh in the back? Should it be filled? It doesn't show up very well in the image. If you fill it, you'd need at least double the ribbon. But then the bottom of the image also shows the mesh filled with white. If you're going to fill five rows around the hips, you need at least another five yards of ribbon.
Another relevant point is that this is really stretchy and has to be well-stretched to fit the bust and hip. If it goes under the corset, then the corset will keep it from riding up at the hip to bunch at the waist, or so I assume, having never tried wearing something like it. If it's over the corset, will it stay in place?
After pondering over the past week and a little bit of fruitless internet searching and writing all of this out, I think I'm going to assume that a "vest" can refer to a garment worn under the corset and that the amount of ribbon is wrong. I will definitely fill the mesh at the front of the bust with ribbon. I'll try it on with a corset to decide whether to fill the back. I don't think I'll fill the hip unless the mesh needs it to stay put, which the try-on should tell me. All that being said, I don't think I'm going to use 1" ribbon; I'll use something that approximately fits the holes without folding it.
Gotta love Victorian and Edwardian knitting patterns.