Quellenforschung

Meaning: source research; the study of a work's sources and influences.

Usefulness: 1 (If I'd known this word earlier, this blog would be the Sir Thomas Urquhart Quellenforschung, or possibly the Quellenforschung* Urquhartian.)

Logofascination: 2 (My German etymology is not so strong; the OED links it to a few other words - including quellen for sources - but they're all either very old or very dialect, or both. Unrelated to quell as in quash.)

In the wild: It was the OED word of the day recently, and LTA dug up a few earlier citations.

Degrees: 2

Connections: quellenforschung - research

Which is used in: Trissotetras; the first paragraph. Sir Thomas is going to discuss angles, so he first needs to explain degrees:

Every circle is divided into three hundred and sixty parts, called degrees, whereof each one is sexagesimated, subsexagesimated, resubsexagesimated, and biresubsexagesimated, in minutes, seconds, thirds, fourths, and so far forth as any computist is pleased to proceed, for the exactnesse of a research, in the calculation of any orbiculary dimension.

This of course only makes sense if you know that sexagesimated means divided by sixty, and that orbiculary is a particularly fancy way of saying round; as you may recall from previous extracts of the Trissotetras, it doesn't get much more helpful. 

*The conjugation would probably be different. If I run into any Germans I'll let you know what it should be.