Little to report. I did my two circuits of Drummond Place Gardens. I did some binding-off and some weaving-in and some baby knitting. I worried about Brexit. We have reached what I believe is called an impasse, in that matter. “Daniel Deronda” has become a shade more interesting and, sure enough, one or two Jews have appeared in its pages.

That was an interesting remark of yours, Tamar, about arsenic being used as a green dye, hence giving that colour something of a bad reputation.

I did a bit of natural dying some decades ago. A soupy brown is far and away the easiest colour to achieve. I was lucky enough to find some ochrolechia tartarea – a lichen – on some stones in Strathardle, and from that got a satisfactory purple and red. It produces purple on its own, red if macerated in urine or vinegar, as you prefer. I never got anywhere near green.

It seems remarkable that people living lives of great hardship, well below what you and I would consider the poverty line, had the time and energy and intellectual curiosity to discover such things. Once you have a market for your knitting, and know that ochrolechia will produce valuable colours, it’s reasonable enough to spend an afternoon looking for it. It’s not abundant (at least, it isn’t in Strathardle) and there is nothing in its appearance to suggest purple. How did it get started?

I suppose success with other lichens provoked someone into trying 'em all.