Counting heads in Auckland and Thames

I've heard a piece of information which has had me puzzling for some time now. Every so often, it pops up again, the way urban legends tend to do so, and those repeating it are usually convinced it is true. It is best summed up by this statement in Wikipedia:

“Towards the end of the last century Thames was the largest centre of population in New Zealand with 18,000 inhabitants and well over 100 hotels and three theatres [in] 1868. For a while it was thought it would replace Auckland as the major town in the area.”

Hmm. Really? I took a look at some of the census figures available via Papers Past for the period 1868 to 1891.

1868
Auckland City & Suburbs 17606
Thames goldfield 2439

1871
City of Auckland (West & East, inc. Newton & Parnell) 17221
Thames 11950

1874
City of Auckland (West & East, inc. Newton & Parnell) 21803
Thames 12271

1878
Auckland City & Suburbs 27000 approx.
Thames (electorate) 12516

1881
Auckland City & Suburbs 38735
Thames electorate 12272

1886
Auckland and Suburbs 39826
Thames electorate 9498

1891
City of Auckland (alone) 30006
Thames Borough 4662

So, where does this all come from, the belief that at one stage during the 19th century, Thames was the largest centre of population in the country (and supposedly out-stripping Auckland)? I think the key is in a number mentioned both by the latter day Wiki article, and by the following from 1964: 18,000.

“Thames expanded explosively and by mid-1868 had a peak population estimated at 18,000. Hammering and sawing went on night and day, as ‘cloth houses’ on frames were replaced by wooden ones from the abundant nearby kauri. Coromandel sawmillers established themselves quickly and from the same area came gold-prospecting machinery.”

A M Isdale BA, "The History of Gold Mining on the River Thames",  Ohinemuri Regional History Journal 1, June 1964

An estimated figure of 18,000 -- so, where did that come from? Apparently from one of the sources used by A M Isdale in 1964, E M Wayte's Thames Miner's Guide from 1868.

The population of the Thames Gold Fields cannot be less than 18,000 souls, men, women, and children. There are upwards of 11,000 miner's rights issued, but many persons who hold shares do not reside upon the diggings.

But, as you'll see above, that doesn't quite tally with the reported census figures for the goldfields for that year. There is another piece of contemporary information, well-publicised in the newspapers of the time.

This, being the period of the anniversary of the Thames goldfield, Mr. O'Keeffe deemed it important to place upon record a few statistics showing its progress during the past year …These steamers, with a single exception, have been built at the port of Auckland, entirely of New Zealand material. Since the 14th of February to the 31st July last, these steamers have conveyed to the Thames 18,000 passengers, and from the Thames 14,000 leaving a margin of 4,000 in favour of the goldfield.

 (Southern Cross, 29 August 1868)

The "fact" doesn't appear to be backed up by contemporary statistics or newspapers reports, and seems based on a wild shot in the dark type of guess. At this stage, I'd say it was optimistic fancy for the time, rather than fact.

Update 3 January 2011: Found this in the Appendices to the Journals of the House of Representatives, from 1871.

The returns from the Thames and Coromandel Gold Fields accompanying this Report will be found on inspection much more complete than those laid before the House of Representatives last year. Considerable care has been taken to bring them as near as possible up to the close of the year ending 30th June. The year just closed promised at its commencement to be one of depression, especially on that portion of the Gold Fields situated at the Thames. A large area of ground had been abandoned, the results being the loss of employment to numbers of working miners, the cessation of crushing operations, and general slackness of trade in the townships. The number of miners' rights issued in the year 1870 was only (on the Thames) 3,296, while in 1869 there were issued 9,435, and in 186S there were 11,585. The population of the field also decreased. As near as could be ascertained, in January, 1870, the population on the gold fields was approaching 15,000, while the census taken in January, 1871, of the whole electoral district of Thames, does not much exceed 12,000. The cause of the depression thus briefly referred to is not far to seek. It is to be found in the wholesale taking up of supposed auriferous country, in the hope of selling it for large sums of money, and the formation of Companies based on value utterly fallacious, the country being entirely unproved, or rather unprospected. 

 Bolding mine. From "Further Reports on the Goldfields of New Zealand", G-31, AJofHR, 1871