How idiotic must Earth's scientific community have been, if some kept arguing that the flashes on Mars were a natural phenomenon even after the third or fourth such event? The Martians were launching their capsules every 24 hours on the dot! No natural phenomenon would be that perfectly-timed.
Old Reliable Geysers, anyone?
There was actually a bit of "truth in television" involved with those flashes: Wells was drawing on reports at the time of "Martian Flares" which some observers believed might be attempts by Martians to communicate with Earth using giant mirrors, but cooler heads of science dismissed as the natural phenomena of light reflecting off Martian clouds and glaciers.
When they see that the "meteorite" is radioactive, the sheriff says he's going to post DEPUTIES to keep an eye on it. We then see later 3 of the men who were hanging around the crash site keeping an eye on it. Were all the deputies at the square dance? Were the 3 deputized? Off duty?
Presumably. It is a pretty small town. The police department's probably not that big.
Also they're there to make sure that it starts no more fires. But they don't appear to have any firefighting equipment and the only vehicle seems to be the one guys pickup truck. What were they supposed to do if a fire did break out? Bat it with their hats?
The stuff they'd use to fight any fires is probably, well, in the back of the truck.
And for that matter, why would you assign to keep an eye on a fire hazard deputies or civilians and not you know, firefighters?
For this one, it is a pretty small town, perhaps not wealthy enough to fund a sufficiently large fire department to enable a bunch of firefighters to be specially posted to monitor a fire that's already been put out in case it goes up again. There may have been other matters they had to deal with as well (other, smaller fires that were caused as a result of the main one). So they may (partially) rely on volunteers to help them out.
Am I the only one that thought it was pretty dumb of the Martians to just forget about all their medicine? They absorbed our blood. It pretty much went, "Ah there we go human blood. Ah crap now I got sick." I mean, I can forgive it for the most part, if their medicine wouldn't work on our viruses, bacteria, or infections.
On that note, what exactly kept any possible Martian illnesses from infecting and killing humanity right back at the end of the story? The 50's movie saying that the "smallest creatures of God's kingdom defeated the invaders" could be taken to mean that He Himself prevented it, but what about the other versions?
That comes direct from Wells. That being said, the emphasis is different: Wells, an atheist, meant it ironically—"Humanity proved itself utterly useless in a panic, and were it not for things like viruses, we'd all be utterly screwed." George Pal, a Catholic, took the quotation at face value, and used it in full Sincerity Mode.
The premise in the book is that the Martians have no resistance to disease because they wiped Mars's native pathogens out thousands of years before. They don't even have digestive tracts for surviving bacteria to live inside.
The Martians have been essentially invulnerable super-geniuses for millennia at this point. They're arrogant enough to believe that insignificant amoeba on the planet where even the dominant species is helpless against them can't possibly be any threat against them. In other words, it's our old friend Hubris.
There's a bit of "truth in television" to the idea as well: the novel was an allegory for British and European colonialism, with human invasions into "primitive" cultures frequently accompanied by comparable run-ins with local diseases (such as malaria) suffered by the invaders.
There's additional "truth in television" in that very useful, utilitarian technologies and techniques become forgotten and lost once they are obsolete. Average First World citizens don't know how to skin animals even though they know intellectually that animals have to be skinned, and that used to be common knowledge three or four generations ago at most. Ancient herbology is making a resurgence due to concerns with modern medicine and side effects, but it's through a smoky haze of uncertainty because we forgot herbology once modern medicines worked better.
It's probably also worth noting that concerns about transmission of alien bacteria are possibly a relatively recent, neurotic, and uniquely human thing based on science fiction of the sort that H.G. Wells first imagined: without Wells pointing the way, we very well might not be very worried today about contaminating the planets we visit with Earth bacteria, or stay awake at night wondering at all the things that might go wrong should we accidentally bring alien bacteria back to Earth from an alien world... without the horror/science fiction Artistic License Biology, why would humans or Martians worry about bacteria that evolved on one world being able to infect aliens from a completely different world?
Jeff Wayne's Musical:
If the Martians are inside their handling machine draining humans of blood, how can the journalist and Nathaniel see this?
Along that same line, The Martians are described as being larger than bears, so how is 1 let alone multiple Martians able to fit inside the machine and at the same time have humans in there as well getting their blood drained?
They might not see the actual blood-draining itself, but might be able to witness enough (person gets dragged into machine; lots of horrible screaming and slurping sounds; dessicated corpse clearly drained of blood is dropped out of the machine) to logically piece together what happens based on context clues. Hence, they "see" what happens. As for the space issue, this is likely a trimmed-for-space issue; the original novel reveals that the Martians are boneless and can manipulate their bodies to whatever shape they need, so they can likely just compress themselves even further if necessary. Also, while the Martian itself is described as larger than a bear, IIRC there's no description of how large the handling machine is; presumably it's large enough to fit more inside than just the Martian if necessary.