A thread on one of the lists is paying homage to those who digitize old books, making them searchable and downloadable. For example, this old text A practical treatise on the manufacture of vinegar (1914), digitized by Google from the library of the University of California, is reviewed thus:

If others know of anything similar that is in the 100-year old range, there may be a wealth of valuable information out there for us - free. I am amazed at the good technical quality available 100 years ago. I am pretty sure the author knew more about charcoal making than anyone alive today. . .

One surprise for me was that those early 1900's charcoal-makers were getting up to 50% more vinegar than char by weight. They valued the char, but nowhere near as much as they valued the wood vinegar. . .

A reply noted that:

The scanning of these old books is proving to be a great gift.

For example the 1846 book on American Agriculture, A brief compendium of American agriculture by R.L Allen, reports a four to ten fold increase in yield from applying charcoal dust.. .

There are 33 references to charcoal in a 452 page book. Fascinating book.

This is a twofer since my expected benefits of freely available and easily usable information include such scenarios as this, and the agricultural use of charcoal is of great interest to me.

It also ties in with fragments of information that I have - some posted about - that notes historical origins of modern agronomic methods such as prediction of El Nino weather patterns by 16th century Peruvian potato farmers (haze in winter skies at night), and soil PH management (by taste) by 15th century Amish dairymen in Europe. I often suspect that more is known than is included in the canon.