What exactly is дольник?

Question

I've been reading a bit about Russian prosody and it's been puzzling me. According to Wikipedia, there are different historical definitions of what дольник means, but most scholars today subscribe to the following one:

Дольник возникает, когда в исходном трёхсложном силлабо-тоническом стихе интервал между сильными слогами (иктами) в случайных местах сокращается с двух слабых слогов до одного.

Meanwhile, by the article on слог,

В русском языке слоги различают по количественной характеристике: сильные (оканчивающиеся на долгую гласную или на гласную+согласные) и слабые (оканчивающиеся на краткую гласную).

However, according to the article on долгие и краткие гласные,

В процессе формирования самостоятельных славянских языков на основе праславянских диалектов в большинстве из них оппозиция гласных по долготе — краткости была утрачена за исключением чешского, словацкого и сербохорватского языков.

After all Russian does not distinguish between long and short vowels...! So my questions are:

1. What are the сильные and слабые слоги?

2. What exactly is дольник? It seems to me that дольник just means each line of the poem has the same number of stresses. However, Wikipedia gives the following example which doesn't really correspond to my understanding:

Его встречали повсюду
На улицах в сонные дни.
Он шел и нес свое чудо,
Спотыкаясь в морозной тени.
(А. Блок)

Any help is very much appreciated!

Answer 1

1. These are stressed and unstressed syllables. Also you can think about them as of weak and stong beats in music. It is "слабая и сильная доли" for Russian. Доля - дольник.
2. So ДОЛЬНИК is a prosodic foot, where stressed syllable goes for strong beat, but for weak beat there are one or two unstressed syllables.

It is like 4/4 time signature, where number is strong beat.

...........1.................2.............3.............4
........Его .. встречали повсюду........ !
......На улицах в сонные дни. ..........!
...Он шел и ...... нес свое чудо, ...... !
Спотыкаясь в морозной тени. ....... !

Answer 2

After all Russian does not distinguish between long and short vowels...!

You confuse commonly spoken language and poetic/song language. Formally, дольник is a kind of accentual verse (тонический стих in Russian; although it is also often referred as "a transitive form" between accentual-syllabic and accentual verse).

And сильный слог in this context differs from "stressed syllable" as in normal speech. Therefore it was also explicitly named "ictus".

What exactly is дольник?

You can think it as a regular iamb or trochee with a few extra (weak) syllables (2-syllable based), or one of regular 3-syllable forms where a few weak syllables are (irregularly) omitted (3-syllable based).

AFAIK, in English and German poetry they don't use a special term for it. So, say, a German speaking person may refer "Ich weiss nicht, was soll es bedeuten, // Dass ich so traurig bin" as "Jambus", while by Russian tradition it should be classified as "дольник".