Found

EBTG. Banished to the Thames

One of my favourite Thames finds carries the promise of an interesting history. It is a small black pouch, with a rusty popper on the front. A heavy iron bolt has been carefully threaded through the back and tied down tightly. Tucked inside is a cassette tape, along with a rectangle of earthenware tile to act as further ballast. Whoever prepared this package wanted it to sink without trace.
Found

The puzzle of the eight thousand map cards

I have an old, homemade chest of drawers in my study. It is barely a foot across, and the drawers need to be wiggled and wobbled to get them open. Filling its five drawers are thousands of small cards. Each has a map glued to it, showing an area of about ten square miles of the United Kingdom. I’ve wondered for years what they were for.