Its clearly hand 'brazed' with cable eyes individually brazed on etc and the lugging all brazed in also. It must have taken quite some time to construct in such a manner without welding etc. I've done brazing myself and it's very time consuming and quite a skill.
All the old frames were made by brazing - remember welding didn't become common for ANYTHING until the 1950s. My father in law worked in a bike factory in the 1960s: frames were brazed in one go fully assembled in a brazing hearth, not each joint brazed individually with a gas torch like today.