These are copies in an unknown hand [the name "Meriel Nevill Watt" appears in the front of the volume] of letters, primarily from Ellis, that were published in the "Philosophical Transactions" of the Royal Society in London. Most relate to botanical topics, and many are written to Peter Collinson. A few are written by Peter Woulfe. Included are contemporary engravings from the "Transactions," as well as original wash drawings copied from the engravings.

These notebooks contain lectures or reports on lectures, with corresponding watercolor and pen-and-ink drawings. There are volumes on geology (Great Britain and elsewhere), natural history, mechanics (sketches of levers, valves, and weighing machines), and steam engines (sketches of mechanics of boilers).