Where in the world is Cape Sheridan?

Having been immersed in all things Peary for some time, we tend to forget that not everyone is intimately familiar with the geography of the far north, and Cape Sheridan is not exactly a well-known spot. In fact it is near the northeast tip of Ellesmere Island, quite close to CFS Alert, but a long way from Brunswick, Maine.

It is a long way from Brunswick, Maine to Cape Sheridan

For us, finding our way there will be a breeze – we will simply fly to Resolute Bay (via Ottawa and Iqaluit). From there, with the support of Polar Shelf, we will board a Twin Otter for the five-hour flight to Cape Sheridan. Once on the ground, finding our way around will be simple too. We will have physical maps, of course, 1:50,000 scale topographic maps now printed on polypropylene rather than paper, for weather resistance. These same maps are also available digitally, so we have the files on our digital devices. But no one goes into the field these days without a GPS, so we’ll have those too, both basic models and something new to try: a GPS receiver for an iPod touch or iPad. The one we have purchased is produced by Bad Elf, and it interacts with the digital maps on our devices, which are there thanks to a great app Topographic Maps Canada. Not only is it great, it is free!

Peary would be very envious. Trained as an engineer, he was always looking for the best equipment he could find, and mapping and navigation devices were on the top of his list. Many of the areas he visited were poorly mapped, so he produced detailed maps when he could. For this he had a customized theodolite.

Peary's customized theodolite

The most obvious customization consists of carefully made leather knob covers, fitted onto knobs a surveyor needs to adjust, to keep the surveyor’s fingers from freezing to the metal. Correspondence between Peary and the manufacturer, Fauth & Co., shows that he also had them make very specific modifications to increase the accuracy of the instrument.

Peary is better known for his geographical discoveries than his maps, however, and these required a different sort of instrument. Until the advent of GPS systems, navigators mostly relied on sextants and similar devices (The one below is actually an octant, with the curved scale representing one eight of a circle, and it belonged to Donald MacMillan).

Donald MacMillan's octant

These instruments measure the angle between the sun and the horizon (among other things) which together with the time, precisely measured, allows a navigator to calculate his location with some precision. Arctic navigation requires some special techniques. In the very high Arctic, out on the featureless frozen ocean, when the sun never sets, it can be hard to know if it is night or day. Peary and his men carried 24 hour chronometers, so the did not risk mistaking the time!

Marvin taking a reading using an artificial horizon

Donald MacMillan's 24-hour chronometer

Finding the horizon on the sea ice can be challenging too. Blowing snow, ground fog, or even a light overcast can make it impossible to tell where the ice ends and the sky begins. To overcome this problem, Peary used a device called an artificial horizon: a small pan into which a pool of mercury is poured, to make a flat reflective surface. A triangular glass ‘tent’ over top protects the mercury from the wind. In the picture above you can see the little tent, while Peary’s assistant Ross Marvin is himself protected by a windbreak made of snow blocks.

The thought of carrying around a flask of mercury seems amazing to us today, and we are very grateful that we don’t need to use a sextant (although archaeologists do still use theodolites, or their modern equivalents to map sites). If Peary had had a GPS there would be no doubt about whether or not he made it to the North Pole, but we wonder what innovations to the device he might have asked a manufacturer to make. We don’t expect anyone to challenge the location of any sites we identify, but it’s nice to know that anyone trying to revisit them in the future will be able to find them with ease.

4 thoughts on “Where in the world is Cape Sheridan?

  1. In Peary’s 1910 recording for the Victor label—which I’ve transcribed—he says: “Winter Quarters at Cape Sheridan on the north coast of Grant’s Land—four hundred and fifty miles from the Pole—were reached September fifth.” I have been unable to find anything on “Grant’s Land” (or “Grantsland,” or even “Grand Slam”)—was this an older name, or the American name, for Ellesmere Island?

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