Jun 012013
 
James Clark Ross

James Clark Ross

Magnetic_North_Pole_Positions

Today we celebrate the anniversary of the first discovery of the North Magnetic Pole in 1831 by James Clark Ross.  He was on an arctic voyage with his uncle Sir John Ross in the side paddle steamer Victory, attempting to find a northwest passage to the Pacific Ocean. Their ship was ice bound for four years, and, in the end had to be abandoned.  During their second and third years of entrapment, James Ross made expeditions overland to explore and map the region around where they were trapped.  It was on the second of these that he discovered the North Magnetic Pole on the Boothia peninsula, the northernmost tip of the North American mainland to the northwest of Hudson Bay, surrounded by islands and shallow straits.

The North Magnetic Pole is different from the North Geographic Pole (called sometimes “true north”). The North and South Geographic Poles represent the points on the earth’s surface around which the earth spins (the axis of rotation).  They shift around a tiny bit, but are basically fixed points. There is actually a third North Pole called the Cartographic North Pole which is absolutely fixed, and is the basis for drawing all maps. The North Magnetic Pole is the point that all compasses point to, and is quite different from the Geographic Pole. It’s the place on the surface of the earth where compasses point vertically down, and it moves around – a lot.  James Clark Ross found it at Cape Adelaide on the Boothia Peninsula. Roald Amundsen found it in a slightly different location in 1903. The third observation was by Canadian government scientists Paul Serson and Jack Clark, of the Dominion Astrophysical Observatory, who found the pole at Allen Lake on Prince of Wales Island in 1947. The Canadian government has made several measurements since, which show that the North Magnetic Pole is moving continually northwestward. During the 20th century it moved 1100 km (683 miles), and since 1970 its rate of motion has accelerated from 9 km/year (5.6 miles/year) to approximately 41 km/year (25.5 miles/year), or 1.3 mm/sec (.05 inches/sec). The map pictured shows its actual position as observed, and its conjectured position since 1600.

I am amused by the quirkiness of the North Magnetic Pole.  First, because it moves AT ALL (due to movements in the earth’s core).  This matters mostly to navigators, orienteers, and anyone else who relies on map and compass to get around places with no obvious landmarks (although GPS has largely replaced such methods, and is more accurate). In the nineteenth and twentieth centuries, the location of the North Magnetic Pole was important for whalers in the region. If you have ever seen an ordnance map you may have noticed in the margin two arrows – one points to geographic north, and the other to magnetic north.  Maps are drawn using cartographic north as the guide, because if you used magnetic north you’d have to redraw them annually.  If all you have is a compass to guide you, you must compensate for the difference between cartographic north and magnetic north.  Second, the needle of a compass is a small magnet with the north pole of the magnet pointing north.  If you know anything about magnetism, a little light bulb will go off in a second.  The poles of magnets attract opposite poles. The north pole of a magnet attracts south poles of other magnets. So if the north pole of your compass needle points towards the North Magnetic Pole, that must mean that the North Magnetic Pole is actually a magnetic SOUTH pole! Cool.

One of the major problems with polar exploration has always been nutrition. Early explorers had precious little understanding of either the calorific needs or the general dietary needs for survival in polar weather.  Working inside a polar station requires about 2,750 kilocalories per day, whereas hauling sleds outside requires 6,500 kilocalories per day (depending on variables such as body mass, temperature, and sex).  Even riding a dog sled requires 5,000 kilocalories per day.  Capt. Scott’s famed 1912 expedition to the South Pole carried 4,500 kilocalories per man per day, which was nowhere near enough when they had to abandon their mechanical transport and ponies, and travel on foot.  Furthermore, the balance of foods was all wrong and they did not compensate for deficiencies such as vitamin C.  As a result several members of the team developed scurvy, including Scott himself. They had too many carbohydrates (almost 50%) and not enough protein and fat. Modern polar workers eat a diet that is 22% carbohydrate, 42% fat, and 36% protein.

Ross’s 4 year ordeal trapped in the arctic would have meant the certain deaths of all the crew of Victory were it not for the fact that the indigenous Netsilik Inuit visited them periodically with food supplies.  Chief of these provisions was pemmican which was about all the Inuit took on long fishing and hunting trips.  It’s a mix of dried and powdered meat, fat, and berries, that was widely used by indigenous hunters in northern and central Canada. Pemmican is actually a Cree word. The Cree are the largest indigenous nation in Canada. I give a modern recipe here which I have modified based on cooking experience, but will confess I have not tried. Closest I’ve come is homemade beef jerky, which is miles better than what you get in stores.  All you need is a rack, a box fan, and a lot of time (several days).  The general consensus is that pemmican is not really yummy, but this recipe seems better than most.  Pemmican is traditionally made with hunted red meat such as deer, moose, or elk, but beef will work. Adjust the fat in the recipe depending on climate, more for colder ones, less for warmer ones.  The simplest way to render suet is to grind it and then heat it on very low heat, stirring occasionally to avoid having the solid bits that remain burn.  Strain the resultant fat through a fine strainer.

Pemmican

Ingredients:

4 cups lean meat ground twice
3 cups dried fruit
2 cups rendered suet
½ cup unsalted nuts coarsely chopped
2 tbsps honey

Instructions:

Spread the meat out very thin on a cookie sheet and dry in the oven at 180° F (80°C) for at least 8 hours or until sinewy and crispy. Check periodically to make sure it does not burn (it’s not wise to do this overnight).

Pound the meat into a powdery consistency using a mortar and pestle or food processor.

Grind the dried fruit, but not too fine.

Heat the rendered fat on medium low heat until liquid.

Mix in a bowl the dried meat, dried fruit, and nuts.

Add the fat and honey, and mix everything thoroughly by hand.

Form into balls about the size of large meatballs and let cool.  Store in an airtight tin in a cool place.

Will keep for several years.

Yield: 15 (depending on size)

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