In direct contrast with the most recent post (It Was A Good Experience!) this brother and sister, while not terrified, probably aren't going to say, "Wow, Mom, may we do that again!" The photographer may not have engaged with them, or they may not have been naturally adventuresome children, but whatever the reasons, we may not be engaged by what we see here either. Technically it is a very good print of an unsuccessful portrait, unless you are charmed by children with concerned, doubtful expressions – as I certainly was in another recent post, Why So Sad, Heart's Darling? It is difficult not to empathize with children. And with the photographers who must photograph them!
Siegel Cooke & Co of New York might agree that this isn't their best work; they can't all be winners. Early 20th century.