If the Martians have the ability to drop things on us from orbit, which they should, then we’re doomed. Obviously the 1898 guys were just toying with us.
Buncha drunken good ol’ boys, gunna go bunny-blastin’ over on that-there next planet?
Drunken Frat hazing party?
Bachelor-party-gone-wrong?
Extreme bar mitzva?
The military in 1898 was a lot more advanced than people think, and IIRC in the book the British take out a few Martian Tripods with artillery and dreadnoughts - it’s not like the (otherwise awesome) concept album where the Martians blow a single dreadnought out of the water and everyone effectively curls into the foetal position and sucks their thumb.
But that is what happens! The guns down one Martian, the Martians evolve to use the black smoke too annihilate the guns, then a single torpedo ram destroyss 2-3 Martians before sinking and that’s the end of the narrated human resistance.
The Royal Navy was, in 1898, the largest and most advanced in the world - there’s no way they lost two ships and went “Well, we tried. Tea, anyone?”
It’s been a while since I read the story, but I recall it mentioning multiple artillery batteries defending London and it stands to reason some of them took out Martian Fighting Machines as well.
Other countries had decent navies in the era too - including the US, Russia, Japan and France.
I rather enjoyed The War Of The Worlds: Global Dispatches, which tells the story of the Martian invasion as it occurred elsewhere in the world - I recall one story set in Imperial China being rather good.
I read it pretty recently and from what I recall the human forces had dug in and prepared various lines of defences in preparation for the Martian advance, they would have most likely defeated the aliens but taken heavy losses in doing so. But that all fell apart when the Martians used the black smoke against them, something a WW1 era gas mask would probably have protected them from.
Most of the battles took place on land so the Royal Navy wasn’t really that involved except for protecting refugees leaving along the coasts.
That does look interesting, thanks for the link 
That’s assuming that their technology advances at the same rate as Earth, perhaps they’ve stagnated at their current level for a long time or improve only gradually and incrementally and humanity can now out-tech them.
Pretty big assumption to hang the future of the human race on of course!
And eventually the Martians are going to make their way near those coasts, and then BOOM! Dreadnoughts.
It’s well worth reading if you can find a copy.
It’s worth bearing in mind that up until World War II, military tech was really geared about re-fighting the last war - hence cavalry units still being a thing in WWI, rifles with iron sights ranged out to 2km, giant defensive structures like the Maginot Line, and so on.
It’s possible the Martians have learned to counter some of the stuff they encountered in 1898, but not the stuff that’s been developed during WWI/WWII/Modern Era military conflicts - resulting in Martian Fighting Machines that are impervious to anything a Dreadnought can fire at them, but get shredded by a AH-64 or an AC-130 or a MiG-29K.
Not enough info to really say?
What kind of chemical weapons? Just saying chemical weapons is kind of generic.
Disperse a widely spreading mist of some chemical that causes living cells to just fall apart turning the person into a liquid mess?
Yea that would ruin anyone’s day in any year.
Something that bonds all free oxygen atoms (in say a 5 square mile area) to something else, like carbon?
Yea suffocation is a bitch
So what kind of chemicals are we talking about?
Because known earthly ones we have ways of combating.
And this deathly heat ray, aside from burning wood what else does it do? how hot it is?
How accurate is it? How fast can it fire? What kind of detection ability does this alien menace have and how small an object can it detect?
If the thing can detect even a small missile approaching, and said ray is hot enough, sure, 1km is plenty to take out incoming missiles projectiles and aircraft.
And what is this “Man” Armored in?
You need to fill in more detail, otherwise we can chose what the aliens have and dont have and simply make it winnable. Can even decide how hard or easy it will be.
Considering the performance of the Imperial Russian Fleet in the Russo-Japanese war, and the state of naval gunnery (abysmal!) in the Spanish-American war, I’m not so convinced that “large Navy” == “decent.” God knows, far more shells wound up in the bottom of Manila Bay than wound up in ships… even at close range (2000 yards) (Spanish accuracy was even worse than the Americans).