He will probably know nothing about the rules by which the compositor gains his results.

The compositor needs to know the rules, but to remember always that they are only means by which to secure results.
There have been several attempts to devise systems of division, but no one of them is thoroughly consistent or universally adopted.
One system requires the division of a word when the pronunciation will permit on the vowel at the end of the syllable.

It has the defect of making no provision for syllables that end in consonants.

Moreover, if rigorously applied it would give us such divisions as _ca-pa-ci-ty_, _cata-stro-phe_, _lexi-co-gra-pher_, _pre-fe-rence_, _pro-gno-sti-cate_, and _re-co-gnize_.
Another system requires the division of consolidated words at the junction of their elements, for example: _magn-animous_ _cata-clysm_ _found-ation_ _oceano-graphy_ _theo-logy_ _know-ledge_ _lexi-co-grapher_ _in-fer-ence_ _pre-judice_ _pro-gnos-ticate_ _pro-position_ _typo-graphy_ In some cases this rule would lead to queer looking divisions.

More serious objections are that the system does not provide for words that are long enough to be divided but are yet not consolidated words, and, most of all, that the average compositor is not an accomplished etymologist and knows very little about the derivation, make up, and compounding of the words he has to set up.