Thursday, 04 June 2020


A solution to Te Whanganui-o-Hei's plaque problem

The story of just where in Te Whanganui-o-Hei/Mercury Bay did Lieutenant James Cook and astronomer Charles Green observe the 9 November 1769 transit of the planet Mercury across the face of the sun is certainly a convoluted one. If it had not been for the perseverance of a famous Cook historian, it is possible this year’s 250th anniversary commemoration of the observation, which established Aotearoa/New Zealand’s geographic coordinates, may have been held on Shakespeare Cliff.

As described in New Zealand historian Frances Porter’s 1978 publication, “A Sense of History,” a memorial cairn was placed on Shakespeare Cliff in 1954 to commemorate Cook’s November 1769 sojourn at Mercury Bay. However, despite the opinion of some that Cook’s 1769 observatory surely would have been on this elevated headland which overlooks the Bay, the plaque on the cairn does not specifically state so.

Why the reticence? Perhaps it was the seeming unavailability of extant charts of the Endeavour voyage - which surely would have accurately confirmed the position of the observatory? Perhaps the confusion could be said to originate from the government initiative in 1903 to recognise historical sites by establishing the seemingly misnamed “Scenery Preservation Board” (1903 - 1953)? In 1919 the Board recommended that 100 acres of land on Shakespeare Cliff should be reserved for scenic and historic purposes. It was not until 1923 that approximately 88 acres was purchased and it was quite some time later before the local branch of the National 1940 Centennial Committee proposed, as a token gesture, a monument or cairn be erected at Mercury Bay which recognised Cook’s historic visit in 1769. A cleared area on Shakespeare Cliff was chosen and after 14 years of procrastination, the cairn was finally completed in 1954. Given the aforementioned confusion, the wording on the cairn’s plaque avoids the subject of observation sites.  

Enter Professor Beaglehole, the preeminent New Zealand scholar regarded worldwide as the leading expert on Cook and his remarkable voyages in the 18th century. It was he who described how he finally solved the mystery of just where James Cook and astronomer Charles Green, aided by second Lieutenant Zachary Hicks, observed the transit of Mercury.

It was while he was in the library of the Hydrographic Department of the Admiralty, poring over preserved charts from Cook’s voyages, that he came across one signed by Richard Pickersgill, master’s mate on the Endeavour. It was a chart of Mercury Bay on which various locations were notated and, it seemed, were important to Pickersgill. It was a “eureka” moment for Beaglehole and, to quote his reaction in his own words, given in an address he delivered at Cooks Beach on 9 November 1969 near the observation site on Cooks Beach, he said, “Picture my triumph and joy, the hosannas which I raised to that remarkable young man, when I found among them the spot where Charles Green and James Cook observed the transit of Mercury on a November Day of 1769.” Beaglehole had positively identified the observation site.

The “spot” where Cook and Green set up their telescopes and quadrants was on grassy land just to the west of the Purangi River mouth, some 300m to 400m from the area known today as the Purangi Reserve. A plinth to mark the site was erected in 1970 but sadly, due to erosion, it was undermined in 2018 and toppled into the sea. Fortunately, the plinth has been recovered, is currently being restored and will be relocated as close as possible to the original site in time for the 250th anniversary commemorative events scheduled for October this year.

Pictured: The plinth marking the Cooks Beach site where James Cook and Charles Green observed the transit of Mercury on 9 November 1769 just after it has toppled into the sea last year.


Latest business rest of site

Marina Park Apartments

Each of our 1, 2 & 3 Bedroom Apartments are fully self-catering with spacious open plan living, fully equipped kitchen and laundry. Each apartment has a generous balcony with a pleasant outlook.


Do you plan to “Support local/Buy Local” wherever possible during the Covid-19 recovery period, even if it means paying somewhat more for items you could have purchased online from outside the wider Mercury Bay area?

The Mercury Bay Informer is a highly popular community newspaper, based in Whitianga. The paper is distributed throughout the Coromandel Peninsula, coast to coast from Thames to north of Colville.