I imagine that Fig 21 "knotted tap joint" and Fig 13, "rat tailed joint" would frequently be merged to create a rat tail joint with an insulated wire extending beyond the joint (the difference in the way the electrical tape was applied). And that the rat tailed joint looks like the ancestor of the wire nut.
Must have been fun to use a solder pot in tight quarters at a junction box in some hard to get at spot... And not fumble the solder pot...
