This is one of the stories I remembered a little about. The most memorable part for me is that this alien splashes down on Earth in Lake Erie, not too far from where I was living as I read the story. That was neat. (Hasse was born in Indiana, the next state over.)
Published in 1936, this story is inspired by the early Neils Bohr atom model -- the one where electrons orbit atoms the way planets orbit suns. This model was scientifically interesting for about six months in the 1913 timeframe and he got a nobel prize for this and other work in 1922. But even he noted that while there were some similarities there were also big, big differences and he quickly refined his model to include orbitals which are something quite different from planetary orbits.
The general public, however, didn't pay attention to the further evolution of the concept so even to this day the atom is symbolized as a nucleus with orbiting electrons. And Hasse glosses over the differences big time in this story. In this story atoms are solar systems on a small scale.
In the beginning we are introduced to a classic mad scientist with a lonely assistant. The assistant, our protagonist, gets volunteered to try out this wondrous invention first. Ouch! Not even any animal testing, we go straight to unwitting assistant testing.
Sadly, on this reading the mad professor/author's concepts feel very contrived. He is monitoring thought waves which are described as completely different from electromagnetic radiation. He's not taking into account that time sense will have to change as he shrinks. And for no reason he invents a new material, Rehyllium-X, with the virtue of being dense. In doing so Miller seems to have a poor understanding of molecular structure. What does Rehyllium-X offer that a simple block of lead does not? I guess it just emphasises that this is not our universe scale.
Nice description of being hunted by a germ. Only problem is that he should have seen this problem coming when he was still huge compared to the germs on the surface. He could have squashed a few and made a safe haven. But... this problem of dealing with microfauna was going to be a problem on every cycle. Hmm.... We will see, we will see.
Ouch! Another thought just hit me. There's no mention of Brownian motion, and no mention of atmospheric atoms. There should be a size range where these forces get quite vicious. Also, there's no mention of clothes. Did those shrink with him, or not? This brings up the question of what Shrinx affects, and doesn't. At this point it is both wondrous and highly contrived.
Oh man! Atoms are clusters of galaxies, not star and planets. I had forgotten this. I don't think it sunk in on the first reading. This ruins the symmetry. I guess this is a way of dodging the Brownian motion issue, but it weakens the story.
An interesting descent to a new planet in this new universe, but so many Technofiction problems. Planetary orbits, unlike atomic orbits, are not fixed. His huge bulk would have changed orbits. His descriptions of the stars and planets of this universe were ignoring things such as the "Goldilocks Zone" where solar radiation is the right intensity to sustain planetary temperatures that would sustain liquid water. He is also not describing gas giants at all. Instead we have colorful stars in fanciful orbits surrounded by mostly earth-like planets. This is a very different universe, indeed, and it's weakening the story for me this time around -- specially the lack of correlation between atoms of the "above" universe and stars of the "below" universe. This revelation is disappointing, and I notice it is ignored by the editors. I think they found it too disappointing to keep aware of.
The description of the first alien encounter is not too bad. They come across as alien and powerful. Technofiction flaws are that there is no indication that the assistant flattened a big chunk of the contient when he landed and he couldn't spot the alien city when he was big. Nice interpretation of the difference in time sense between the aliens and the assistant. That is well handled.
The primative jungle world that comes next I remember as being weak the first time I read it, and it's even weaker this time. This really contrived and getting really old when I'm only part way through. It's becoming a survey of sci-fi theme worlds and a story with a moral. <sigh> The following worlds are better in the sense that they are more interesting to me, but not enough to hold my interest. There is still too much inconsistency.
It's an ambitious effort, but his handling of scale as the protagonist shrinks kept me out of belief suspension.