Halley is now three months into his first voyage and I thought it was time to write about his logbook or journal, as they were called at that time.
Fig 1. First page of the log of Halley’s first voyage, in another hand (© British Library (£), Add MSS 30368 f.1r)
Halley’s first journal is written on plain paper, roughly 41cm high by 27cm wide. It covers 17 sides, with the last side being an appendix, which I’ll describe at the end of the voyage.
The log is not in Halley’s hand but presumably that of his clerk, Caleb Harmon, and so the spelling and punctuation of the tweets are Harmon’s, not Halley’s. If you read the log straight through, there are one or two places where you get a sense of Halley giving dictation, of seeming to conclude a sentence, pausing, and then adding another phrase – which I found rather thrilling.
The first page (Fig 1) begins with this heading:
A Journall of a Voyage in his Majesties Pink the Paramore entended for the Discovery of the Variation of the Magneticall Compass by Edmund Halley, Comandr.
Note the spelling ‘Paramore‘ and ‘Edmund‘, which I’ve written about previously.
The journal has three distinct formats, which illustrate the evolving style of ships’ logs in the late seventeenth century. The first two sides and most of the last two sides are in diary form, with each entry written alongside the relevant date, though Halley sometimes combines events that occurred on different days, as he does in the first entry for October 20 (“…and that next day…”).
Fig 2. Page from the log of Halley’s first voyage, in another hand (© British Library (£), Add MSS 30368 f.2v)
In between these pages, the journal comprises data tables, interspersed with more general text (Fig 2). The tables reflect late seventeenth century administrative reforms, an element of which, was to standardise the logs of ships. In these standardised logs, data relating to wind, course, miles covered, latitude, longitude and bearings of landmarks last seen were entered in columns on the left-hand page, while any remarkable occurrences were entered on the right-hand page. The tables in Halley’s journal are a modified version of these.
There are nine tables of consecutive days, with the shortest covering two days (January 1-2) and the longest forty-three days (Jan 6-Feb 17). I didn’t intend to tweet this data initially, as it doesn’t make for very interesting tweets, but then decided that too much useful information would be lost if I didn’t, such as tracking Halley as he moves south through the latitudes and seeing the drop in wind and miles covered when he hits what we now call ‘the doldrums’.
The general text that sits between the tables is the most problematic to tweet. It appears to have been written sometime after the events it describes and a date is rarely assigned to the text, and while there are clues that enable you to work out the relationship between the days covered – “this morning”, “the next day”, “that evening” – without some hint of a date, you cannot identify on which dates the individual days’ events fall. In these instances, I have looked for as many internal clues as I could to try to work out the most likely dates, but in some places the clues are so few that I have simply spread the entries across the dates between the tables in a way that hopefully makes sense. The trickiest passages of all to tweet are those where he refers to events on a specified date in the future, then in the past, and then returns to the present. I hope these entries won’t be too confusing when they occur!
The handwriting throughout is neat and easy to read. The greatest difficulty was deciding whether certain initial letters were upper or lower case: an initial ‘s’ frequently looks like a capital (‘Some’ and ‘Several’ as well as ‘Sea’ and ‘Sand’), while an initial ‘p’ almost always appears to be lower case (‘portsmouth’ and ‘plymouth’). In places where I really couldn’t decide, I have usually followed Thrower.
And speaking of Thrower, his published version (from the Hakluyt Society) has been enormously helpful. I made my transcription by hand, typed it up into tweets, checked it against Thrower’s, and then went back and checked any differences against the manuscript. As a novice transcriber, having another transcription to check mine against was a great benefit – I might not have embarked on the project without it.
Halley's Log 
Awesome
Hi
Have you established what the daily measuring routine was aboard the ship? Whose compasses were used and how was their accuracy maintained? Did anyone have the slightest notion of Deviation? Also I am supposing that they were using Lunars for Longitude?
Please direct me to the places in your text where this is answered. Thank you.
Hi Max, thank you for your comment. I had once planned to write about the instruments he used on the ship, but didn’t as I didn’t some across enough concrete information about what instruments he took or about his routine. He measured longitude by both observation and account (the method used is usually noted in the second logbook, but not often in the first), but his longitude by account is much less reliable as he had difficulty reading the currents, especially those in the South Atlantic.
He did subsequently write about the impossibility of using a long telescope to observe Jupiter on a moving ship, and he also wrote about the barometer he used in the Phil Trans (see the penultimate paragraph here).
The principal purpose of the voyage was to measure compass deviation, and I discussed the Instructions for his voyage here (the Instructions for the first and second voyages are almost identical). I wrote a bit more about finding longitude here and here – though looking at these posts again, I find I need to revise them, as he didn’t really talk about using magnetic declination to find longitude before he discussed it on his Atlantic Chart. I’m lightly revising some of the posts (and fixing broken links) before I set them as the Featured Post, so I’ll get round to tweaking those two fairly soon.