I was going through the book, "Raj Yoga" by vivekanada, and i found a breathing technique, where he mentions that the practitioner should inhale for 4 beats, hold the breath for 8, and exhale for 4 beats. He mentions that this is the simplest and the easiest pranayam, and that western people will have no problem doing this.
I found that most of what he was teaching, he kept it simple as most of the attendees to the lectures were western people and without any initiation or understanding of the indian yogic system. He sometimes drops a hint that there are dificult forms of pranayam, some of which may need empty stomach or special dieting or more control over the breath.
These hatched three questions inside me.
what other different pranayama techniques that he mentioned? (can you mention with reference)
Which pranayama techniques he practiced himself?
how did he came to know or discovered these techniques?