Infinitives used as imperatives?

Question

There is a passage in The Moonstone (by Wilkie Collins, 1874) which is full of infinitive forms of verbs. ("To xxx").

What I find hard to explain is that despite the infinitives, this passage clearly functions as an imperative / directive. It contains a list of instructions to be followed. For instance, the phase "to walk out on the South Spit" would have made perfect sense without the leading "to".

Although this seems like an incorrect use of the infinitive form, it makes perfect sense and doesn't grate on me as I read it.

I feel like I've occasionally heard or written other text in the same form.

Is this just a "poetic" style which isn't strictly a correct use of the infinitive? Or is it really some other 'tense' which is not actually the infinitive at all?

"Memorandum:—To go to the Shivering Sand at the turn of the tide. To walk out on the South Spit, until I get the South Spit Beacon, and the flag-staff at the Coast-guard station above Cobb's Hole in a line together. To lay down on the rocks, a stick, or any straight thing to guide my hand, exactly in the line of the beacon and the flag-staff. To take care, in doing this, that one end of the stick shall be at the edge of the rocks, on the side of them which overlooks the quicksand. To feel along the stick, among the sea-weed (beginning from the end of the stick which points towards the beacon), for the Chain. To run my hand along the Chain, when found, until I come to the part of it which stretches over the edge of the rocks, down into the quicksand. And then to pull the chain."

(Online source. Italics are as in the original.)

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Thinking about it more, it almost seems to be a type of future tense.

Answer 1

The quotation in your question omits two key items from the original:
1. that the quoted paragraph starts with the word "Memorandum:—"; and
2. that the following text immediately precedes your quotation:

I turned to the more interesting object of investigation which was presented to me by Rosanna Spearman's letter. The address was written as follows:--"For Franklin Blake, Esq. To be given into his own hands (and not to be trusted to any one else), by Lucy Yolland."

I broke the seal. The envelope contained a letter: and this, in its turn, contained a slip of paper. I read the letter first:

"Sir,—If you are curious to know the meaning of my behaviour to you, whilst you were staying in the house of my mistress, Lady Verinder, do what you are told to do in the memorandum enclosed with this—and do it without any person being present to overlook you. Your humble servant,"Rosanna Spearman."

I turned to the slip of paper next. Here is the literal copy of it, word for word:

Specifically, that text includes the instruction, "do what you are told to do in the memorandum enclosed with this ..."

That the list with the 'sentences' all beginning "To ..." is a list of instructions to be carried out by the recipient of the letter: that is why they all begin "To ...". In fact, the word "To" could have been omitted from the beginning of each instruction, such that the items in the list begin:

Go to the Shivering Sand at the turn of the tide.
Walk out on the South Spit, ....
Lay down on the rocks ... ...

With the word "To" omitted from each instruction, they are in the normal format for instructions:
"Do this ...; do that ...; etc."

So it's not a "poetic style"; nor misuse "of the infinitive"; nor "some other 'tense'" - but just a list to instructions!

Addendum:
A comment to my answer asked why the instructions start with "To do" rather than just "Do".

I have no 'definitive' answer to that. What I would point out is that the book dates back to the the 1870's: I wonder whether the form "To do ..." (rather than just "Do") was used at that time.

In any case, we do still talk of a "To Do list", and a "List of things to do", so (to my mind) there does seem to be a close connection there.

Answer 2

As Mitch noted above, "I want" is understood. By adding "I want" each sentence would be commonplace declarative, but the passage would lose its poetic effect. The repetition of "to" functions as alliteration and holds the passage together. Also, the passage takes place by the sea, and the repetition is likely meant to reflect the constant pounding of the waves.