The Strange Case of Thomas Green

Thomas Eustace Green Manuscript. Macmillan Brown Centre for Pacific Studies. 1865. All Rights Reserved. Permission of the Macmillan Brown Centre for Pacific Studies must be obtained before any re-use of these images. Permission of the Alexander Turnbull Library, Wellington, New Zealand, must be obtained before any re-use of the images of Gabriel’s Gully (PA7-45-11 and MNZ-0336-1/2-F).

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The slideshow above offers a sample of images from Thomas Eustace Green’s journal, which he kept while panning for gold and tending shop at Gabriel’s Gully in Otago, New Zealand, between 1861 and 1864. You can find out more about the Otago goldrushes here.


Thomas Green was born into a period of rapid cultural change in Port Levy, New Zealand, on March 12th 1840. Only weeks before, a large proportion of Maori chiefs had signed the Treaty of Waitangi which (as far as the British government was concerned) ceded sovereignty of the country to the British crown. This resulted in an influx of European colonists to the country, a process that accelerated considerably after the discovery of gold at Gabriel’s Gully in 1861. Green descended from the Ngai Tahu and Ngati Wairaki tribes, located in New Zealand’s South Island. Very little is known about him between his birth and his appearance in Wellington in 1861. References to him can be found in colonial newspapers, but his tattered journal is the only significant source we have for him. It records his whakapapa (genealogy) and the period between 1861 and 1864 that he spent on the Otago goldfields, along with some scattered references to later years. As can be seen from the slideshow, Green’s diary is a rather remarkable, and in many ways inscrutable, document. Aside from prosaic descriptions of Green’s daily life, including his battle to stop himself gambling at the local billiard tables, the journal is largely filled with encoded passages, along with prose and diagrams apparently transcribed from encyclopedias concerning astronomy. He was particularly interested in the perihelion (the point in an elliptical orbit of a planet or comet that is nearest to the sun) and the star cluster Pleiades, which in Maori tradition is called Matariki. Its appearance on the eastern horizon in June signals the Maori New Year, and is central to the rhythms of Maori hunting and gathering.

Clearly Green was reconciling the newly arrived European intellectual traditions with his received tradition; his journal is an early and energetic example of  cross-cultural intellectualism. It should come as no surprise that he later became an early Ngai Tahu intellectual and ‘translator’ between traditional maoritanga (cultural traditions) and western rationalism. Green’s journal is an artifact of considerable importance, and its content is all the more remarkable given it was written in the harsh conditions of southern New Zealand while he was living in spartan conditions. It is, after all, a record of two thought systems meeting over 2000 years late: Greek and Maori astronomy meeting in the mind of a billiard-playing shopkeeper in the tent city of Gabriel’s Gully. This is not to suggest his information was out of date: in addition to writing the Greek alphabet out in full he listed all the main planets and noted their Greek symbol, their distance from the sun, and the length of their year. The list includes Neptune which had been found less than 20 years earlier in 1846.

I’m grateful to Te Maire Tau at the University of Canterbury for putting me onto Green’s journal, and Peter Wilson at the Ministry of Health for sharing some of his knowledge about the Greek language, Greek astronomy and mathematics (all failures of interpretation rest with me). We’ve each had a go at interpreting it over the last two years. Te Maire dug up the biographical details outlined above and noted some key points of interpretation in terms of Maori culture (such as Ngai Tahu’s practice of marking fishing and hunting grounds by star navigation); Peter identified the Greek letters and noted the basic letter-replacement encryption for the first two ciphers; and I’ve cracked his code to one level (see below), but we are really little closer to a definitive interpretation than when we started.

Cracking the Code

Green’s journal includes what is clearly a cipher page (see below). Ciphers I and II are keys to simple letter replacement systems, each containing 26 symbols.

There are no page numbers on the manuscript, but on a page headed ’1864 Dunstan Clyde’ , just after a striking note that he noticed a “strange phenomenon at 12 pm”, there is a sentence that stands out: ‘Begin with Benjamin’.

If you perform a simple letter replacement on the symbol sequence above the words “strange phenomenon” using Cipher I, the name ‘Benjamin’ is spelled out.

Code cracked, apparently. The problem is that the cipher only works for the first 8 letters; the last 7 letters remain indecipherable, and none of the other ciphers appear to work. And Cipher I doesn’t work in this straight-forward way for any other symbol sequences I’ve had the patience to examine. One possibility is that Benjamin’s surname is present elsewhere in the journal: if this is the case we would presumably be able to backward-engineer the appropriate cipher for this second level of encryption. There is a list titled ‘My Mates’ earlier on in the journal, which prompted me to think about this possibility, but it doesn’t include a Benjamin. Given the very rough state of the journal (it is literally falling apart at the seams), it may be that a key page has been lost. And of course it could be that the missing key was only ever held in Tom’s head; in either case we may never fully decipher his notes. One point to note is that several symbols appear in his journal that aren’t included on his cipher page. Realizing this was effectively the end of the game: without a cipher for those symbols it will be very difficult to fully crack the code. That noted, he did join the Odd Fellows when he moved north during the 1870s, and like many secretive societies they have been known to encode their writing. It may well be that he picked up some techniques while moving around the mass of itinerant laborers and gold miners during the 1860s and someone out there recognizes those additional symbols. If the journal is publicized some bright spark might just crack it one day, so if anyone out there has some ideas, do let us know.

So the strange case of Thomas Green remains unresolved. One thought that has come up is that he is playing a trick on us, but this doesn’t seem likely given the journal wasn’t written for public consumption and so much of it is encoded; it must have been laborious to document his thoughts in this way and it doesn’t seem likely he would do this on the off-chance it would provide entertainment for later generations. One last thing to note, perhaps, is that the document wasn’t handed down through the generations as a particularly treasured item, in fact it was only recently put into archival care. Graduate students in historical  method might like to chew on the significance of that one.


  • Where do the symbols come from? Some are Greek letters and symbols for the planets and stars, but others may have been made up by Green himself or be part of a system of code unknown to us.
  • How did Green use the other 4 ciphers on his cipher page?
  • Is this a standard encryption system, or one of Green’s own making?
  • Are there any hints in the later mathematical problems that are included at the end of the journal?
  • What was he hiding? The obvious answer seems to be potential gold finds, but aside from some small nuggets which he generally sold for cash to be spent at the billiard table, he was never a rich man. One extended ‘paragraph’ of code is titled ‘Fish’ and seems to have a quite different sentence structure to his main entries, which suggests he may have used his system for more than one purpose. On a more prosaic level, he may have encoded his journal because he was recording personal thoughts that he didn’t want others to read.



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