Mr Surveyor Thomson, by John Hall-Jones

Early Days in Otago and Southland

This is the first proper biography of John Turnbull Thomson, Chief Surveyor of Otago and later first Surveyor-General of New Zealand. As stated in the subtitle, it is also the story of early Otago and Southland, since the two provinces were surveyed and mapped by Thomson in the days when they were one. Written by Thomson‘s great grandson, John Hall-Jones, this biography was later superseded by a second book (“John Turnbull Thomson. First Surveyor-General of New Zealand”) published in 1992.

Born in Northumberland (England) in 1821, Thomson emigrated to Malaya at the age of 16, then moved on to Singapore 5 years later. There, he distinguished himself for surveying the colony, and for his engineering works. The construction of the Horsburgh Lighthouse, which still stands today in the Straits of Singapore, was arguably one of his greatest achievements, but also took a severe toll on his health, forcing him to return to England.

Thomson arrived in New Zealand in 1856; he was preceded by his reputation as a surveyor he had acquired in the far east, and was soon offered the post of Chief Surveyor of Otago. After taking on the job, Thomson surveyed Bluff and Invercargill, then embarked on two long reconnaissance surveys, during which he mapped Southland and North Otago, explored the headwaters of the Tasman River and measured Mt Cook. During his stay in Dunedin, Thomson wrote a book about his experiences in Asia, “Some glimpses into life in the far east“, from which a few extracts are reproduced in this biography.

In 1874, Major H.S. Palmer was sent from England to observe the transit of Venus, and after touring all the provinces of New Zealand, issued a report on the state of the surveys in the colony. Palmer’s report was devastating; it was only in Otago that he found a system that satisfied his standards. On Palmer’s recommendation, the New Zealand government formed a national Survey Department with headquarters in Wellington, and in 1876 Thomson was appointed first Surveyor-General. Three years later he resigned and retired in Invercargill, where he passed away in 1884.

While on his reconnaissance surveys of Southland and Otago, Thomson explored and named a number of geographical features, including Lindis Pass, Grandview Mountain, Black Peak, Mount Pisa and Mount Aspiring. The chapter on the naming of the latter needs re-writing, since new information has recently come to light (see this link). Thomson also named Mount Sefton (‘Mt Stokes’) and other features at the head of the Tasman River, but his nomenclature was ignored and replaced by Julius von Haast a few years later.

Thomson was not only a capable surveyor, but also a talented artist, and left behind a number of paintings, a few of which are reproduced in this book. John Hall-Jones’ work is a pleasure to read, well written and enriched with many extracts from Thomson‘s own diaries. Many black-and-white photographs and maps add to the quality of the text. Since much additional information about Thomson has come to light in recent years, the book “John Turnbull Thomson. First Surveyor-General of New Zealand” should be used as a main source of biographical information.

Reference

Hall-Jones, J. (1971) Mr Surveyor Thomson: Early Days in Otago and Southland. AH & AW Reed, Wellington, New Zealand. 146 pages

Maori Nomenclature, by W.H.S. Roberts

Reprinted from Otago Daily Times

“When I landed in New Zealand in 1855 the Europeans had the opportunity of seeing more of the Aborigines than they have at the present time, as the numbers have greatly decreased, especially in the Middle Island. The melodious Maori language was then spoken by the Natives in its pristine purity, whereas now it is intermixed with so many English words Maoricised, that it is difficult to determine which are pure”.

Southland pioneer W.H. Sherwood Roberts was one of very few early European settlers who recognized the importance of recording Maori lore and nomenclature before it fell into oblivion. He took notes from oral interviews with Maori elders, then published a series of articles in the Otago Daily Times and other newspapers, which were later collated into a number of books.

This volume, Maori Nomenclature, delves into Maori legends, history and nomenclature as well as early European history for Westland, Nelson, Marlborough and Akaroa. Other regions of the South Island are dealt with in Place Names and Early History of Otago and Southland, in Maori Nomenclature: Names in Canterbury…, and in Maori Nomenclature: Early History of Otago.

The book has a decidedly disjoint feeling, as it is collated from a series of independent newspaper articles. Much information is replicated, many anecdotes being repeated with identical wording in back to back paragraphs. Without an index or any maps, retrieving any specific piece of information may feel like searching for a needle in a haystack. It is thanks to Robert’s work, however, that many Maori place names for geographical locations throughout the South Island have been preserved. Many of these place names were later accepted by the New Zealand Geographic Board, and feature as the official names on today’s maps.

Reference

Roberts, W.H.S. (1912) Maori Nomenclature. Otago Daily Times, Dunedin, New Zealand. 103 pages

Maori Lore of Lake, Alp and Fiord, by Herries Beattie

Folk Lore, Fairy Tales, Traditions and Place-Names of the Scenic Wonderland of the South Island

One of Herries Beatties’ most famous works, Maori Lore of Lake, Alp and Fiord combines Māori history and tradition, legends and nomenclature. Much of the information was gathered orally from the author’s informants, old Māori or pakeha who had become well acquainted with their culture. What makes the book both unique and invaluable is the fact that much of the information had never been published before, and it would have been lost forever, had Beattie not gone to the effort of putting it in writing. Asides from many stories and legends, 268 Māori place names were published for the first time in this book. 

Maori Lore of Lake, Alp and Fiord is structured in 3 parts. In Part I, The Lakes, Beattie delves into the Māori’s connection with the great lakes of the South Island. Starting from Nelson Lakes, the author moves gradually south to the waters of Inland Canterbury, West Otago and Southland. Lakes Wakatipu, Wanaka, Manapouri and Te Anau receive special attention and provide the bulk of the material published in this section. In Part II, The Alps, Beattie explains the origins of the Māori names for most prominent peaks, and the legends that gave birth to these names. Most stories are associated with the Mount Cook region, or the area around Haast Pass. Māori routes across the Southern Alps are also discussed. In Part III, The Fiords, Beattie summarizes what little information he was able to gather about the Māori nomenclature of Fiordland. If the paucity of the material disappoints, the author makes up for it with a wealth of stories about the wild natives, and the encounters between early European navigators and the Fiordland Māori. In my opinion, this is the most interesting and fascinating part of the book.

Like all other books by Beattie, Maori Lore of Lake, Alp and Fiord is not an easy read, being both chaotic and disorganized. In spite of the appearance of some logics in the overall structure of the volume, the material is scattered all over the place without any sensible connection. Repetitions abound, as do sudden jumps from one topic to another. At least there is an index, which makes it possible to track down specific information. Asides from 12 (rather disappointing) black and white photographs, the book is also notable for a lack of illustrations and maps, which makes it very hard for the reader to locate many of the geographical features described by the author.

Possibly the greatest limitation in Beatties’ work lies in the lack of local knowledge by the author of most areas he describes. While he gathered much valuable information from Māori sources, Beattie was faced with the non enviable task of matching this information with the maps of areas he was not familiar with. This means that most Māori names may be correct, yet several may be associated with the wrong geographical feature and modern English name. Here the reader really needs to apply a lot of caution. In spite of these limitations, this volume remains one of the prime sources of information about Māori lore and nomenclature in the South Island, and is one of the principal references for modern dictionaries of Māori place names.

Reference

Beattie, H. (1945) Maori Lore of Lake, Alp and Fiord. Otago Daily Times and Witness Newspapers Co. Ltd., Dunedin, New Zealand. 150 pages

The Naming of Mount Aspiring

How a surveyor’s mistake put a name on the map for the highest peak in Otago

History books tell us that on December 18^th, 1857, John Turnbull Thomson was the first European man to see Mount Aspiring from the top of Grandview Mountain. In his diary, he wrote: “At the head of Hawea, dist. about 40 miles, is a very lofty [snowclad] peak which I called Mt Aspiring” [1,2].

The Naming of Mt Aspiring – original entry in JT Thomson’s diary. From JT Thomson’s fieldbook 47. Image made available for reproduction by Land Information New Zealand, Christchurch office. Click on the image to enlarge

The word between “lofty” and “peak” is pretty much illegible, and while historians seem to have settled on “snowclad“, it has also been interpreted as “conspicuous“, “arrogant“, “snowbound“, “conical” and more. For a more detailed essay on the subject, and on the actual meaning of the word “Aspiring“, see the chapter on the Naming of Mt Aspiring in George Griffith’s excellent book “Names and Places in Southern New Zealand” [3].

More intriguing in my opinion is the choice of the wording “at the head of Hawea” – is this really where Aspiring stands when seen from Grandview Mountain? Did Thomson refer to the wrong lake?

As I have now proved in conclusive manner, when Thomson wrote the above sentence in his diary, he was not at all looking at Mt Aspiring. He was looking at Mt Aeolus instead. My findings were further corroborated when photographer Gilbert van Reenen, from Wanaka, with whom I have now exchanged much information on the topic, independently came to the same conclusion. Later on I learnt that Ken Thomlison, a school teacher from Wanaka, had repeated J.T. Thomson’s triangulations some 15 years ago. Although he had noticed the anomaly in the measurement of Mount Aspiring from Bluenose, he had assumed it to be a typo, and had failed to recognize that Thomson was actually looking at a different peak.

Below follows a detailed explanation on how I identified the correct mountain, then confirmed my theory by repeating J.T. Thomson’s calculations, and on how the name “Aspiring” was transferred to the mountain that bears the name today.

The first seed of doubt
Thomson’s painting of Lake Wanaka
Thomson’s map of the interior of Otago
Thomson’s theodolite measurements
The trig stations on the Lindis Range
The chief surveyor’s mistake revealed
Ken Thomlison’s research and interpretation
Elevation measurements of Mt Aspiring

The first seed of doubt

At the end of August, 2010, I climbed Grandview Mountain with two friends, Jaz Morris and Nina Dickerhof. This was an ‘innocent’ trip – all we had set out to do was to camp on the summit and admire the views that had prompted Thomson to bestow such an inspired name. We carried two tripods, cameras and spare lenses, then made ourselves comfortable near the cell phone tower, waiting for the cloud to clear to photograph the highest peak in Otago. But when Aspiring shed its veil, we could not hide a sense of anti-climax – the summit barely showing above the high ridges of Mt Alta, there was nothing conspicuous or attractive in the mountain we had come to see. Is this really the peak that caught Thomson’s imagination? Not only that, but Aspiring really isn’t at the head of Hawea!

Mt Aspiring from Grandview Mountain. Just showing above the high ridge of Mt Alta, this disappointing view was not what we were expecting! Photo D Hegg

On the other hand, a much more conspicuous mountain stood out in the nor’westerly clag, right there at the head of Lake Hawea, where we were expecting it to be…

Mt Aeolus – It’s at the head of Hawea, it’s conspicuous, it’s conical… This is the one! Photo D Hegg

On this trip, I carried with me a copy of J.T. Thomson’s painting of Lake Wanaka from Grandview Mountain, which is reproduced on the cover of John Hall-Jones’s book “Mr Surveyor Thomson” [4]. I was confronted with a second puzzle, when I realized that the painting was not at all taken from Grandview Mountain, nor from the high ridge to the east. The location of the painting was further south – but where? Three days later, I was back trying to solve the mystery, and embarked on a solo walk up the Grandview Track towards Trig Hill.

Thomson’s painting of Lake Wanaka

Thomson was a talented artist, and his paintings of Lake Wanaka are testament to his skill. His paintings, however, were not drawn in the field – they were drawn at home, at times years later, from rough pencil sketches hurriedly jotted during his surveys. Thomson’s sketches were not particularly accurate, and he always greatly exaggerated the vertical dimension. While his paintings deserve admiration as work of art, they should not be taken as truthful or accurate representations of the landscape. This can make it quite difficult to identify the exact locations they were taken from.

Thomson’s paintings of Lake Wanaka are derived from a pencil sketch drawn on the inside back cover of his surveyor’s fieldbook 49 [5].

J.T. Thomson’s sketch of Lake Wanaka from Trig Hill. Inside back cover of Thomson’s surveyor fieldbook 49. Image made available for reproduction by Land Information New Zealand, Christchurch Office. Left click on image to enlarge

The first painting of Lake Wanaka was reproduced on the front cover of John Hall-Jones’ book “Mr Surveyor Thomson” [4].

J.T. Thomson’s first painting of Lake Wanaka. Image reproduced from the front cover of John-Hall Jones’ book “Mr Surveyor Thomson” (1971)

The second painting is in a colour plate in John Hall-Jones second biography of his great-grand father, “John Turnbull Thomson. First Surveyor-General of New Zealand” [2].

J.T. Thomson’s second painting of Lake Wanaka. From John Hall-Jones’ book “John Turnbull Thomson. First Surveyor-General of New Zealand” (1992). Left click on image to enlarge

While it has always been assumed that the sketch was drawn on Grandview Mountain, because this is where Thomson wrote the entry in his diary, a field visit suggests that the location must have been further south along the Lindis Range, somewhere near Trig Hill. The fact that the sketch is drawn on the inside back cover makes it impossible to position it in relation to other entries in the fieldbook. On my trip up the Grandview Track, I identified two locations from which I could align parts of Thomson’s first painting.

Location map for the first European painting of Lake Wanaka. See text below for explanations. Left click on map to enlarge

From the first location (point A on the map above), just below Trig A3L8, I was able to align Mt Iron with Roys Peninsula. The course of the Clutha River and Black Peak however do not match their positions in the painting.

View of Lake Wanaka from just below Trig A3L8 (Point A on the map). Photo D Hegg

From the second location (point B on the map) I was able to obtain a good alignment of the Clutha River and of Black Peak; other features however are out of line. Most important, at point B there is a striking rock platform that very much resembles the foreground in Thomson’s first painting. It is easy to imagine Thomson sitting on one of the natural seats at the edge of the platform to take a rest and draw a sketch of the surrounding views. The natural feature in fact is so striking, it would be hard to imagine anyone not stopping here for a good rest!

View of Lake Wanaka from the striking rock platform just north of Trig Hill (Point B on the map). Photo D Hegg

It is interesting to notice how the rock feature, so prominent in Thomson’s first painting, does not appear in his pencil sketch. Did Thomson fill in the gaps from memory? Or did he draw other sketches in the field, which were lost and are no longer preserved today? Either way, I suggest that it is not possible to align Thomson’s paintings, and that the original pencil sketch should be used on any future trips to pin-point the exact location. The sketch however was drawn from the vicinity of Trig Hill and not from Grandview Mountain, and the rock platform just north of Trig Hill remains a very likely candidate for the location where Thomson sat down to draw the magnificent vista.

So far I have shown that the story of the naming of Mt Aspiring is not quite as simple as it looks at a first glance. Thomson’s painting was not drawn from Grandview Mountain, and the peak that Thomson named “Aspiring” is more likely to be Mt Aeolus. But should I expect people to believe me on the evidence of a couple of photographs? Obviously not. Further evidence is required, and the next logical step is an examination of Thomson’s maps.

Thomson’s map of the interior of Otago

After his reconnaissance survey of the Interior of Otago, Thomson (or his draughtsmen) drew a number of maps. One of them is preserved at the Hocken Library, and it is notable for the mis-spelling of the peak’s name, “Aspring” [sic], more than for anything else. In all maps, Mount Aspiring‘s location is exactly where we have it today – which seems to contradict all of my conjectures thus fur.

The earliest map of all, stored at the Dunedin Office of Archives New Zealand, is a joy to look at. It’s a very large map, beautifully drawn by hand with ink and is very well preserved. This map gives an interesting cue – a question mark next to the name “Mt Aspiring“. It’s the only question mark on the whole map.

Map of the Reconnaissance Survey of the Interior Districts of Otago Province, 1857-1858, by JT Thomson. Archives New Zealand/Te Rua Mahara o te Kāwanatanga, Dunedin Regional Office, Item DAAK/9429/D450/9. Left click on map to enlarge

What does the question mark mean? It seems that Thomson was not sure about the actual location of Mt Aspiring. And yet, he correctly drew the mountain where we have it today. How could this be? The only way to find out was to get hold of his original surveyor’s fieldbooks, and to check his triangulations.

Thomson’s theodolite measurements

Thomson’s original fieldbooks are preserved in good state at Land Information New Zealand. Stored at the Invercargill and Dunedin offices until recently, they were all moved to the Christchurch office in November 2010. The measurements from the Lindis Range are in Thomson’s surveyor fieldbook 49, “Reconnaissance Survey of part of the Interior portions of Otago Province”. Thanks to the notes in this fieldbook, I was able to reconstruct Thomson’s triangulation system in its entirety. After repeating his calculations, I had conclusive evidence that the peak seen by Thomson from Grandview Mountain was Mt Aeolus, not Mt Aspiring. I was also able to trace down how it was Thomson’s own mistake, when he assigned the name “Aspiring” to the wrong peak on the map. If you’re interested in the maths, read on.

Below is an example of a page in Thomson’s fieldbook. All measurements were written in pencil while in the field, then traced with ink pen in the office.

Extract from J.T. Thomson’s surveyor fieldbook 49. Image made available for reproduction by Land Information New Zealand, Christchurch office. Left click to enlarge

This is the first time the name “Mt Aspiring” appears in Thomson’s triangulations. The measurements were taken from the top of Bluenose, a 1223m high hill located 3km south of Grandview Mountain. What do the names and numbers above mean?

The page title (“Hill End“) describes the trig station from where the measurements were taken. Its geographical coordinates are X,Y and are unknown.

The first line in the table below the title describes the “reference point” (Grandview Mountain in this case); this is the trig point the theodolite is pointing to. By definition, it gets a bearing of 0° or 360°.

Lower down on the page are the names of other trig points (or peaks) measured from the above trig station, with the bearing (accuracy to two decimals) in relation to the reference point. In this case, Hawea Peak (Lindis Peak today) is 93.30° clockwise from Grandview Mountain, when seen from the trig on Bluenose.

When interpreting the above measurements, it is essential to remember that some of the names used by Thomson do not match the geographical features that bear those names today – Grandview Mountain being a good example. Thomson’s Grandview Mountain was the high ridge 2.2km to the east of trig A3PH, which is named “Grandview” on today’s maps. It is only by reconstructing the whole triangulation system on the Lindis Range that we are able to confirm the correct location for each of Thomson’s trig stations.

So, how do we calculate the coordinates (X,Y) for the trig station the measurements were taken from? There is an infinite number of points, from which Lindis Peak is at an angle of 93.30° from Grandview Mountain. All of these points are located on the arc of a circle. Once we add the second measurement (Mt Pisa) to the equation, we can identify the one and only trig point from which the measurements were taken (the intersection of two arcs). With anything more than 2 measurements, the system of equations is overdetermined (we have more equations than unknowns). If all of the circles still intersect in one point, we can be absolutely sure that we’ve got our maths right.

How do we solve the overdetermined system of mathematical equations? Thomson used a graphical approach – he did it on a drawing board, with paper, pencil, compass and ruler. Today, we can easily get to the same results with the assistance of mathematical software. Below is the explanation for the method I used.

J.T. Thomson’s triangulation system – an example. This map matches the first three lines of page 10 in surveyor’s fieldbook 49 (see illustration above). Left click on map to enlarge

(X,Y) are the unknown geographical coordinates of the trig station the measurements were taken from, and x_i,y_i are the geographical coordinates of the peaks and trig points measured from trig station (X,Y). Under the assumption that the earth’s curvature can be neglected (OK provided we work with small distances), I have assigned to each point (x,y) planar coordinates according to the NZTM system.

For each measured peak/trig point, the angle α from the true north is calculated as follows:

where n can take any integer value between -3 and +3 depending on which quadrant the angle falls in.

In the example above, specific for the measurement of Lindis Peak from Bluenose, the angle β between the reference point and the true north is then calculated as β = α – 93.30°. Notice that the value of β must be the same for all trig points/peaks measured from a trig station. The overdetermined system of equations is thus solved by calculating a value of β for each measurement i from a trig station, then through numerical iterations the coordinates (X,Y) that minimize the sum of square differences of all β from their mean.

The trig stations on the Lindis Range

Thomson left Dunedin on 7 December 1857 and travelled up the Waitaki River into the lower Ahuriri, then over Lindis Pass into the Lindis River, and up onto the ridge tops south of Station Creek [2]. On December 16, before crossing Lindis Pass, Thomson climbed Longslip Mountain, from where he took several measurements. On December 18 and 19, he traversed the Lindis Range over Grandview Mountain and Lindis Peak, and took measurements from 8 more trig stations [5]. A selection of his measurements from Longslip Mountain, and from the trig stations on the Lindis Range, are reported in tables below. The header row in each table contains the name of the trig station used by Thomson, followed by its current name, and its NZTM coordinates. All other rows in the table contain the original names of the peaks/trig points triangulated by Thomson, their current names, and Thomson’s theodolite bearings. Any notes or comments follow below each table.

From Longslip Mountain, Thomson measured a prominent unnamed “Cloudy Mt“ to the west. This was his first measurement of (the real) Mount Aspiring. It is significant that all of the peaks measured by Thomson are well to the east of the Main Divide of the Southern Alps, with the exception of Mount Aspiring, which was partially obscured by cloud. The weather pattern must have been from the north-west, with clear skies over the Lindis Pass, and a wall of cloud hanging over the Alps.

Thomson’s measurements from Longslip Mountain contain at least one mistake, in that he confused the high point of the Hector Mountains (2307m) for Double Cone. It is also worth noting that Thomson’s Mt Pisa was the striking rock formation (shaped like a leaning tower) 2km north of the actual high point (elevation 1916m on today’s maps), and that his “Grandview Mountain” (originally “Black Knob“) was not the peak called “Grandview Mountain” today, but the high ridge 2.2km to the east. The elevation we call “Grandview Mountain” today is not at all visible from the summit of Longslip.

Thomson’s “Two Paps Mountain” was Breast Hill. In this case, however, he took a bearing on the wrong elevation – Little Breast Hill. The question mark in his notes suggests that he was aware of the mistake.

Thomson renamed “Black Knob” to “Grand View“. This is where he got his first view of the Lakes Hawea and Wanaka, and wrote the famous entry in his diary. Notice how he didn’t take any bearings on Mt Aspiring – only hills well to the east of the Main Divide. And again, he mistook the highest peak in the Hector Mountains for Double Cone.

The name “Mt Aspiring” appears in Thomson’s measurements from the top of Bluenose for the first time. The bearing falls bang on on Mt Aeolus. See the photograph of this page in Thomson’s fieldbook reproduced above.

Thomson renamed “Hawea Peak” to “Lindis Peak“. Presumably, this is because he realized you can’t see Lake Hawea from its summit. He also took a rare measurement of a snowy peak on the Main Divide, Mt Pollux – was this a sign of clearing weather?

J.T. Thomson’s second measurement of Mt Aspiring. Surveyor fieldbook 49. Image made available for reproduction by Land Information New Zealand, Christchurch office. Left click to enlarge

 

Thomson’s measurements from the tops south of Dip Creek (many thanks to Ken Thomlison for rectifying an earlier mistake of mine in locating this trig station). Here, Thomson took his second measurement of “Mt Aspiring“. This time he took a bearing on the real Mt Aspiring, not on Mt Aeolus.

The chief surveyor’s mistake revealed

The last set of measurements from spot height 1172m on the tops south of Dip Creek is key to understanding how the name “Mt Aspiring” was assigned to the peak that bears the name today – and not to the “lofty [snowclad] peak” which Thomson admired from Grandview Mountain. Because of nor’west clag on the Main Divide, Thomson was only able to take two bearings on “Mt Aspiring” – the first one, from Bluenose, was on Mt Aeolus (the peak that Thomson originally named “Aspiring“), while the second, from the tops on the true left of the Lindis River, was actually on Mt Aspiring.

It is my belief that while taking observations from his last trig station, Thomson made a simple mistake – he confused one mountain for another. This is easily explained by the fact that the Southern Alps were hidden in cloud, the most prominent peaks being visible only a few minutes at a time, probably never showing a full view of their slopes and their summits.

This map shows J.T. Thomson’s theodolite bearings on Mt Aeolus and Mt Aspiring. Thomson was able to take only 2 bearings on Mt Aspiring, and when he realized that they didn’t converge, he resorted to a measurement on a “Cloudy Mt” from Longslip Mountain. Left click on map to enlarge

Once back in the office, while drawing his first map, Thomson would have quickly realized that the two bearings on “Mt Aspiring” did not intersect where they should have – because they were taken on two different mountains. Thomson knew that one of the bearings had to be wrong, but he had no way of working out which one – hence the question mark on the map. This is where the measurements from Longslip Mountain come back into the equation – Thomson had taken a bearing on a “Cloudy Mt“, which intersected quite nicely with the second of his bearings on “Mt Aspiring“. He thus discarded the first one, the one he had taken from the location he named the peak from. This is how Mt Aeolus, “the very lofty [snowclad] peak at the head of Hawea” was wiped from the map, and the highest peak in the region got its name. A peak of which Thomson caught a few glimpses through the cloud at best, and yet, in spite of the mistake, the most appropriate recipient for the inspired name.

Ken Thomlison’s research and interpretation

After publishing the above paragraphs, and a full-page article in the Wanaka Sun by Gilbert van Reenen, I was contacted by Ken Thomlison, who added a few interesting points I had missed in my research.

Ken Thomlison's sketch map, kindly provided for publication

Ken Thomlison noted the following points:

1. In his fieldbooks, Thomson refers to the west and east head feeders of Lake Hawea [5]. He believed the bay stretching towards the neck to be an arm of the lake fed by a river at its head. In his map, Thomson drew the “west head” as extending to the north-west. When seen from Grandview Mountain, Mt Aeolus is roughly at the head of the “west head” – which explains the phrase “at the head of Hawea”.

2. Thomson’s map shows an unnamed mountain (labelled as “D” in the sketch above) which lies exactly on the bearing for Mt Aeolus taken from the summit of Bluenose (notice however that while the bearing is correct, the distance is not – Mt Aeolus is further north)

3. Thomson would have obtained a “visual bearing” for Mt Aeolus from the summit of Grandview Mountain, which (combined with the theodolite bearing from Bluenose) allowed him to roughly place Aeolus on the map.

Ken Thomlison then provides an alternative explanation for how the name “Aspiring” was assigned to the peak that bears the name today:

When Thomson was constructing his map he realised that he must have seen two different peaks, but in his fieldbook he had named them both “Mt Aspiring“. For one mountain he had two intersecting bearings and so could calculate its height at 9135 feet. From his field observations and estimated distances he concluded that the other mountain must be lower. Thomson decided the higher mountain would ultimately be shown more impressive and so he chose to name it “Mt Aspiring“.

While the points 1. and 2. above are valid, I doubt 3. is entirely correct. The segmented line drawn in the above sketch is rather arbitrary, and even a small deviation in its angle would have made a big difference as to the position of Mt Aeolus. I believe that we should refrain from giving too much weight to the actual position of the above mountain – drawn only lighlty in ink, without a name or an elevation, it was added to the map simply to tell us that there are more peaks in that general area, rather than to describe an actual mountain.

I disagree with Ken Thomlison’s explanation about Thomson making a deliberate choice in the naming of “Mt Aspiring“, since it is at odds with the question mark on the map. If Thomson had been aware of the fact that he had measured two different mountains, and had intentionally chosen to name the higher one “Mt Aspiring“, then why put a question mark on the map? The issue about the peak’s elevation however is an interesting one, and needed looking into. As I’m about to show below, Ken Thomlison’s assumption is entirely incorrect. Thomson’s calculations of Mt Aspiring’s elevation in fact provide undisputable evidence of the fact that Thomson thought all along that he had been looking at the same one mountain – even when drawing the map.

Elevation measurements of Mt Aspiring

Thomson’s elevation measurements were simple vertical angles from the horizontal. Combined with horizontal distance measurements, these angles can be used to calculate vertical distances, as shown in the figure below.

How to calculate a mountain's elevation from a vertical angle measured with the theodolite

J.T. Thomson took two elevation measurements for Mt Aspiring: the first one (0 degrees 50 minutes) was on the ‘Cloudy Mountain” measured from Longslip Mountain, while the second one (0 degrees 53.5 minutes, averaged from two observations) was on Mt Aeolus from the summit of Bluenose.

As shown in the figure above, to calculate a mountain’s elevation H from the measured vertical angle β we need to know the elevation h of the trig station where the theodolite is placed. The only trig station Thomson’s map gives us an elevation for is Grandview Mountain, 4703 feet high – this translates to 1433m, 29m lower than the trig’s elevation on the current maps (1462m). I have thus assumed that Thomson had underestimated the elevation of all of his trig stations in the area by 29m – which puts Longslip Mountain at 1465m of elevation, and Bluenose at 1194m of elevation.

Thomson was able to triangulate Cloudy Mt / Mt Aspiring and place it on the map – he would have thus been able to calculate its correct distance from Longslip Mountain, 76.985km. At an angle of 0°50′, this translates to an elevation of 3050.6m. For his measurement from Bluenose however he did not have an accurate distance, but only an “about 40 miles“. Well, 40 miles from the summit of Bluenose, at an angle of 0°53.5′, translates to an elevation of 2521.4m. The average of the two measurements is 2786m (9140feet), only 5 feet higher than the elevation for Mt Aspiring shown in Thomson’s map (2784m/9135feet). It is clear that Thomson took an average of the elevation measurements he took on the two peaks – which bluntly denies the hypothesis that he was aware he was looking at two different mountains. He assumed all along he had been looking at one Mt Aspiring; his bearings didn’t match, and he was unsure as to its location – hence the question mark on the map.

References

[1] p65 in Thomson, J.T. (1858) “Reconnaissance Survey of the Northern and Interior Districts of the Province of Otago”.  Surveyor fieldbook 47. Land Information New Zealand, Christchurch office.

[2] Chapter 10 in Hall-Jones, J. (1992) “John Turnbull Thomson. First Surveyor-General of New Zealand”. McIndoe Publishers, Dunedin, New Zealand. 114 pages

[3] p39-41 in Griffiths, G.J. (1990) “Names and Places in Southern New Zealand”. Otago Heritage Books, Dunedin, New Zealand. 104 pages

[4] Hall-Jones, J. (1971) “Mr Surveyor Thomson. Early Days in Otago and Southland“. AH & AW Reed, Wellington, New Zealand. 146 pages

[5] Thomson, J.T. (1858) “Reconnaissance Survery of part of the Interior portions of Otago Province”. Surveyor fieldbook 49. Land Information New Zealand, Christchurch office.