The first four columns track the parts as they are first introduced in the earliest recorded literature that I have been able to examine*.

The second four columns then attempt to track at least the next iteration of the part.

The source is given in every case and has been recorded as faithfully as I could muster, though inevitably human error will have thrown in the odd 34.

Where there are split rows in the second set of four columns it is to track any subsequent journey that the part went on - particularly if its part no. changed.

Lastly there is some commentary on anything that I found interesting - generally things that I missed and that Clive pointed out!

The last column is my view on which part(s) best answer the question or in some cases to emphasise why they don't.

[* generally this has been pictures and scans of material kindly supplied by Clive, material on NZM and in HCS vol.6 or in a few cases literature from my own collection.]