Interconnected short stories or a novel? Depends upon how you look at it.
Which is fitting, giving that vision is a central organizing theme, even if it remains implicit throughout these five stories.
Andrea Barrett is the historian of science's favorite author, penning a number of stories and one novel about scientists in the nineteenth and early twentieth century. She returns to that stomping ground here, though this collection is the slimmest, I believe--which might have to do with the acclaim she has received and the pressure to put out a book--and also the most integrated. It's reminiscent, in its way, of Jennifer Egan's "A Visit from the Goon Squad," which similarly blurred the boundaries between short-story collection and novel, though that structural parallel is really the only one.
The first story, "The Investigators" (1908) details the coming of a young Midwestern boy, Stan, to an uncle's property in New York, where he meets a number of eccentric characters who are imbued with an amateurish but infectious love for scientific investigation and technological tinkering. "The Ether of Space" (1920) flashes us forward in time, though not so distant in space; it is a story of a science writer trying to get her mind around the fact that some physicists had not embraced Einstein's theories and held out for the existence of a untouchable ether, in order to make the existence of life after death thinkable. She is also trying to deal with a son who seems alien to her--though he is alive.
"The Island" (1873) is, literally and figuratively, the book's center, dropping us back to the origins of all this American science, with Louis Agassiz--known only as the Professor--setting up a summer island retreat for budding scientists. Here he tries to inspire a new generation even as he is being passed by--he holds on to Creationism while his young charges are energized by evolution. One of them will become a science teacher who we meet again (before) in the first story.
Sam, the boy from the second story, grows up to be a geneticist, whom the reader meets again in the fourth story, "The Particles" (1939). He is aboard a ship that is one of the first casualties of World War II, along with other scientists returning from a conference, As he is rescued, along with his teacher, we learn that his scientific pedigree goes back to Agassiz--and like that of his distant intellectual ancestor, he has a penchant for the wrong theory. He is drawn to the idea of inherited characteristics, but is shown up by a fellow student, who also wins away from him the affection of his beloved, and, so Sam thinks, the appreciation of his teacher. But just as Stan, in the first story, mis-understands his parents, so does Sam here, not realizing, until Story's end, that he has always been the favorite.
The various strands climax in the final story, "Archangel" (1919), about Stan's military adventures at the end of World War I in a distant Russian frontier, where X-ray machines are a valuable commodity, to valuable to be used on his injuries. Already we knew of this battle from the second story, when the science writer's family was making goods to send to the poor soldiers here.
At its heart, then, the stories here about how we see the universe, and what we cannot see. Whether inheritance is naught but the movement of material beads on a strong. Whether the universe is empty or full--of stuff, of spirits. Whether X-rays can see what really ails us--and whether they can alter those beads we call genes. And so the recurring motif through these stories is the blind cave fish, also known as the X-ray fish, which puzzled evolutionist and creationist alike: how did it evolve? Was it perfectly created as it was? What does it see, this X-ray, of the universe and its functioning. The first story ends with Sam submerging himself in a pond to see if he can find some of these fish, let loose in New York to discover if they would re-grow eyes: we are all looking, but through the water darkly, as it were.
The ending of that first story is perhaps the best of them all, weird and wonderful, and evocative while not being completely reducible to the mechanics and symbolism of the story or those that follow. It works on its own and as part of a loosely connected novel--which is what raises the question about how we are to understand this book. I wish others were as ambiguous.
Instead, these stories seem relatively rote. By now, Barrett has developed her narrative voice to a fine point. But nothing here seems to challenge it. She provides plenty of historically-rooted examples in a mannered yet precise way. The stories could have come from any of her collections--the voice in them all is the same. (This obviously makes the book a great deal different than Egan's.)
What sets her books apart, though, is the interweaving of science and fiction: her attempts to make the scientific enterprise fully human. That doesn't quite work here, though. The science is either completely peripheral, explained in long bits of exposition or stilted dialogue--or it is too obviously a symbolic mirror for the rest of the story.
Ironically, in a collection this connected, the science and the narrative never feels integrated.