I recently wrote a piece for the Bulletin of the Scientific Instrument Society, re-examining Gerard Turner’s exceptional work on the tooling patterns on early English optical instruments. By re-organizing Gerard’s data it is possible to sharpen up his findings: the patterns dramatically simplified over time, and there is a hard and fast divide between each of the three chronological groups he identified, with Cock and Yarwell dominiting the first, John Marshall the second, and Edmund Culpeper the third. Undoubtedly, these early telescopes are a highlight of collecting antique scientific instruments.

But there is another group of early English instruments, about which we know far less. These are the lignum vitae ‘little perspectives’ that must have been made in large numbers, given the frequency with which they turn up on the market. Here is the basic form (an example that recently sold on Fleaglass):

This example is 159mm long. There is a very similar example in the Science Museum (inv. no. 1918-142). But at least two other sizes are known – a 230mm version, and a smaller 114mm version. Both of these forms were recently offered by Tesseract:

Generally these are said to date from around 1700 to the middle of the seventeenth century. But they are mysterious: there are similar but not identical to the ‘little perspective’ instrument offered by John Yarwell on his famous trade card:

An ideal candidate for the maker would be George Willdey (1676–1737), who offered a wide range of instruments and toys from his brilliantly named ‘Great Toy, Spectacle and Print Shop’ on Ludgate Street. But Willdey’s trade card doesn’t show quite this instrument. Thomas Willdey, George’s son, is another possible candidate.

Do any readers have more information? As far as I know nothing has been published about these beautiful and enigmatic devices! More to follow, hopefully…