Charles Green, Royal Observatory Greenwich Assistant and stand-in Astronomer Royal

Rebekah Higgitt reveals how ROG assistant Charles Green became a stand-in Astronomer Royal, and joined Cook on his first voyage to view the transit of Venus in Tahiti.

Lucinda Donnachie: Hi, I’m Lucinda Donnachie, and today I’m talking to Rebekah Higgitt, Curator of History of Science and Technology at the ROG. Hi, Becky.

Rebekah Higgitt:

Over the past few months we’ve been meeting Assistants at the ROG. Who will we be meeting today?

Well, I wanted to introduce you to Charles Green today, who was one of the Royal Observatory Assistants in the 18th century. And the reason that I’ve been thinking about him, is that I’m one of the curators here at the Observatory, along with Richard Dunn, Curator of Navigation, who are working with the University of Cambridge on a long-term academic project about the history of the Board of Longitude.

The longitude story is quite familiar to people through Dava Sobel’s book ‘Longitude’, and through the story of John Harrison and his clocks, which we have on display at the Observatory. But there’s a lot more to what the Board did, over the hundred and twenty-odd years that it was in existence. And there’s a lot more to the story of technology and navigation in science and the Navy and so on, that we want to explore. And since Charles Green was one of the people working at the Observatory, he’s quite an interesting case; he’s linked to the Harrison story, but he displays more beyond just that. So today, we’ll talk about him.

He started at the Royal Observatory in 1760, and he links in with some of the main figures of the longitude story: Harrison of course, as we’ll find out; also James Cook, Captain Cook, as well. And he had the unique distinction of an Assistant at Greenwich, having worked with three different Astronomers Royal.

Does that mean he worked at Greenwich for a really long time?

Well, actually not that long. He was actually only associated with the Observatory itself for about five years, and for some of that time he was actually away on a sea voyage as well. But he was there for a period of quite a lot of change. He arrived towards the end of the third Astronomer Royal, James Bradley’s tenure, just before he died. And so he was there when the next Astronomer Royal Nathanial Bliss came in. Bliss turned out to be quite unwell himself, and he died after only a couple of years in position. So Green was there under Bradley, towards the end. Under the whole of Bliss’s time and then he was also there just as Nevil Maskelyne started as Astronomer Royal, and he also worked with Maskelyne earlier on the sea voyage, which we’ll come back to.

So let’s go back a bit. Do we know much about Green’s early life? What sort of person gets to be an Assistant at Greenwich Observatory?

Well, we always know frustratingly little about these kinds of people, particularly at this period; there’s not very much in the historical record. What we do know really, is from a very brief biography that was written by William Wales who was another astronomer, an Assistant at Greenwich for a while, and ended up being Green’s brother-in-law. So he knew him fairly well. But there’s not a great deal; it’s very brief. So we do know that he was born in Yorkshire, that his father was a farmer, and evidently a fairly “considerable farmer”, as Wales put it. Pretty well-to-do, because his eldest son evidently received a very good education; he was a clergyman, he was a schoolmaster. He founded a school indeed, in Westminster as well. And Green seems to have, Charles Green that is; seems to have received most of his education from his brother at that school, and later became a master at the school as well, teaching himself, presumably mathematics mostly. But we don’t know much else really beyond that, before he rolls up in Greenwich in 1760, as an sssistant to Bradley. Aged about 26, at that stage.

What kind of work did Green do at the Observatory?

Fairly routine, mundane work. This is the basic work that Greenwich Observatory was involved in, for most of its existence, really. It was about assisting the Astronomer Royal with the routine observations, done with the large instruments set up on the Meridian Line, the instruments that you can still see in the Meridian Building at the Observatory today. And most importantly for the Assistant, in helping with the mathematical calculations that you needed to do with the data that came in from the observations themselves; they needed to be manipulated, made useable by people, not just astronomers at Greenwich, but by astronomers all over the world, and of course by navigators all over the world as well. So that’s what the Assistants were really there for: they were literally human computers: they took the numbers, they did number-crunching. Whole bits, loads of, you know, trigonometry and that kind of thing, to make them into useable data.

But that said, because Bradley and Bliss as well were both quite unwell while Green was there, he was effectively in charge of the Observatory himself for some of the time. So he was a sort of Astronomer Royal stand-in for some of the period, so both towards the end of Bradley’s life, and then also towards the end of Bliss’s life, Green was really officially in charge of the Observatory for a while, and he tided over the period between Bliss’s death and the arrival of Maskelyne as Astronomer Royal. So Green gets the distinction for an Assistant at this period, of actually having his own observations printed with Astronomer Royal’s observations as well, and they appeared in Bradley’s official observations; some time after Bradley’s death, those came out.

So we know that Green was a good observer: indeed his brother-in-law William Wales says that. He said “He was a most excellent observer”. Wales is a bit more sort of dismissive as well in his account. He says he was “tolerably well versed in most branches of mathematics”. I’m sure he was actually pretty good, particularly at the kinds of things that he needed to do. He also said he had a “tincture” of some other sciences, which is rather nice; a bit of smattering. But he also said that he was really keen on sort of more metaphysical kinds of questions as well. Indeed, seems to sort of hint that he might be a bit of a bore on that kind of area, which I kind of like the idea, that he went, sitting there in the Observatory with probably only one other person, the Astronomer Royal, or on a sea voyage, kind of boring people with his ideas and his knowledge, in that sort of area.

He also says that he loved a jest as well, and he could make himself enemies in that kind of way. So perhaps not a real people person, but someone who might have been interesting to get to know, I suppose.

Could you tell us more about the voyage you just mentioned? >
Becky: Yes, this is really perhaps one of the most interesting things about Green, as well as his sort of stand-in Astronomer Royal status, is the fact that he was involved with two really important voyages; important scientific voyages of the 18th century. In the first one he was appointed by the Board of Longitude, so we get that in as part of the Longitude Project, along with Nevil Maskelyne, who was later Astronomer Royal, to travel to Barbados onboard ship in order to test John Harrison’s fourth timekeeper: that’s H4, the sort of watch-like timekeeper that we have on display at the Observatory; to see if it was eligible to actually win the Longitude Prize.

So Green and Maskelyne were both responsible for checking the accuracy of the watch; seeing how well it performed, and also performing astronomical observations that they could use to compare with the performance of the watch. Also testing out the lunar distance method as an alternative way, or an additional way of finding the longitude for navigation. So that was a very important voyage. It led to some disputes with Maskelyne, although they seemed to have quarrelled a bit, but Maskelyne still was prepared to support Green later in his career, so obviously didn’t completely undermine the whole relationship. And there was also, as people probably know, a lot of disputes between Maskelyne and Harrison, and Green was obviously involved to some degree with those as well.

But the second voyage that he made was perhaps even more famous. He was appointed, this time by The Royal Society, to be an astronomer, an observer, on the voyage that later became known as Cook’s First Voyage. So that’s the voyage beginning in 1796, on Maskelyne’s recommendation, as I was saying. It’s interesting to know that Green was actually paid twice as much as Cook was for that voyage, so his expertise was evidently really valued. And the two of them were being paid by The Royal Society for the particular purpose of viewing the transit of Venus in Tahiti in the South Seas, along with other expeditions, so that they could try and use that observation as a way of measuring the distance between the earth and the Sun; that was the whole reason for going off to measure the transit of Venus, and the many expeditions that took place in the 18th century for that, at this time. He also made other astronomical and meteorological observations as well. And the voyage also, sort of slightly less officially, was being sent out to try and find a southern continent, find Australia. So Green was involved with all that very important scientific exploration that we think of as part of Cook; Cook’s legacy, and so on. Cook also has described Green: we’ve got some quite nice things from his journals about him being “indefatigable” in making and calculating the longitude and latitude, making these observations on the journey.

And apparently he was also very good at teaching, which may go back to his early career at the school; teaching other officers to do observations themselves as well, which was probably very useful for both Cook and Green. Although Cook seems to have also raised some questions about the reliability of the way that Green recorded his observations. But that said, those observations by Cook and Green were published by the Board of Longitude later on, so they were obviously seen as something very important, worth recording and something, aside from Harrison, that the Board of Longitude was spending money on at this time.

This must have made Green pretty well-known and respected on his return?

It might have done. We know that there was, as I say, some questions about the reliability of what he was doing. And there was always, evidently a problem at the time, for people at the time who were trying to make a living in astronomy, of going from position to position, post to post, journey to journey, so who knows what would have happened. But the thing is, Green actually died, sadly, on his way back, in 1771 on the voyage. He developed both scurvy and dysentery, which did for him, perhaps not surprisingly.

Cook’s journals also seem to hint that Green didn’t really help himself. I’m not sure quite what he could have done about dysentery. Scurvy he might have been able to sort of stave off a bit. But Cook says that he ought to have taken better care of himself, and is saying that he actually lived in a manner that greatly promoted the disorders that he had. So it may have been something to do with this indefatigable work and observation that he was doing. Or maybe something quite different, but we can’t really tell more from the record than that.

So he was only really in his mid-thirties when he died. It’s a fairly short life, but fairly eventful one as well. And I think, as I say, there’s this great problem of making a name for yourself and making a living as an astronomer, if you don’t have a wealthy patron, or if you don’t have money yourself in the 18th century, so I think Green certainly carves out a name for himself in history.

A sad end to an eventful life. Becky, thank you.

Thank you.

If you’d like to know more about the Longitude Project, please visit And look out for the web resources, podcasts and blogs, events and exhibition over the next few years.

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