Cannot understand some points like:
With Her head bowed - is bowed here adjective or verb? How to explain it grammatically?
Eyes upon the ground - means over the ground?
…, For I have never heard …
Why is for stands here?
What the different between among-amongst, midst (middle)
In this case, ‘bowed’ is an adjective. In your example, you could similarly say “her head was bowed”, if that makes it easier to understand.
“Eyes upon the ground” in this case means that she was looking at the ground. So, with the previous part included, it means that she bowed her head to look at the ground.
In this sentence, “for” is a very formal/literary way of saying “because”.
Is the “for” still used in modern English in term of “because”?
One more thing is that a can’t find some reductions:
I know one thing that 'ud please her," remarked Cap’n Bill, turning his round face with its fringe of whiskers toward the two girls and staring at them with his big, light-blue eyes wide open.
what is 'ud ?
It’s a pretty plant that stands in a golden flower-pot an’ grows all sorts o’ flowers, one after another
Here o’ and an’
Jus’ as soon as one fades away, another comes, of a different sort, an’ the perfume from ‘em is mighty snifty, an’ they keeps bloomin’ night and day, year in an’ year out.
what is Jus’
Those tend to be short forms for when certain American accents are used in writing.
that would please her
and grows all sorts of flowers
just as soon as…
Yes, but only in literary contexts like theatrical performances. It would never be used in normal everyday conversation.
I think it’s something you might hear in old movies or in a bit of a fancier context, not in everyday language. It’s not very common in everyday language. But i think it’s easily understood.
There’s a popular older kind of folk song that goes, “For He’s a Jolly Good Fellow”— ie, they are toasting him (through song) because he is a jolly good fellow. But it’s kind of an old-fashioned song.
Just thought of a phrase where it’s used in modern English-- you might “just for the taste of it” (which used to be the slogan for Diet Coke in its advertisements.) Basically it means, because of the taste.
Alas, the idiosyncrasies of the English language! 
How to explain language construction of form “will have shown to”?
So, as noted, the English in this story is a bit dated and not used in normal speech today.
The phrase “I will have you shown to rooms” could be said “I will have someone take you to rooms…” In this case, “shown” means “taken to,” but in a positive and polite sense as if you’re doing someone a favor or helpful deed.
The sentence, as written, is passive, meaning the speaker is not the one doing or receiving the action.
thanks
I don’t think this is a good example of “for” being used in the sense of “because”. If I say “I drank it for the taste of it” I’m not sure it means “because” any more than, say, “I drank it for you”. It’s not a causal relationship, it’s closer to a reason/motivation given. In this context I think “for” just means “for”, as in, “for what reason (i.e., why) did you drink it?” The fact that you can’t directly replace “for” with “because” in your sentence is possibly giving it away: “just because the taste” isn’t grammatically right, whereas if I say “I did it, for I thought it would be good”, then I can say “I did it, because I thought it would be good”. I think “for” has a meaning naturally close to concepts of “causes/reasons”, but it only strictly means “because” when it’s used as a preposition between two complete sentences. (I could be wrong about a lot of this though, I’m only using my intuition.)
Yes, “for” as “because” is mostly just used in literature, and maybe very formal speaking, but in casual speech it isn’t used much. I think it is good to understand it, though, because it is used in writing a lot.
'For" being interchangeable with “because of” in miriaml5’s example is more common.
As nashlam said, “for” has kind of a close meaning anyway.
The most common phrase I can think of “for” being used before a reason in spoken, casual English, is “for the fun of it.”.
A: “Why did you do that?”
B: “For the fun of it.”
“I just ran for the fun of it.”
Etc.
You might also hear,
“For the hell of it.” Which just means, “I don’t really have a reason, but I wanted to do it.”
*Note: hell is sometimes considered a swear word, so don’t use this in formal speech, at work, etc.
Example:
A: “Why did you do that?”
B: “For the hell of it.”
A: “Why did you do that?”
B: “Why not?”
A: “Why did you do that?”
B: “Just because.”
They all can kind of mean, “because I wanted to do it.”
You can say:
“I exercise for my mental health.”
“I exercise because it improves my mental health.”.
I exercise because my mental health is not good otherwise.
You cannot say:
“I exercise because my mental health.”. It isn’t a complete thought.
If you say, “I exercise because of my mental health,” it sounds better, but still kind of unnatural.
