In 1821 Lieutenant (afterwards Admiral) Anjou was sent to make a more accurate survey, and to discover the land reported by Sannikoff to the north of Kotelnoi Island. He crossed the ice with _narti_ or dog sledges, but at a distance of 40 miles north of Kotelnoi he was stopped by unsafe ice on two occasions. On April 9th he started over the ice to the eastward of New Siberia, and again met with thin ice at a distance of 60 miles from the land. His conclusion was that all efforts to advance on sledges to any considerable distance from the land would prove unavailing owing to thin ice and open water. He completed a survey of the New Siberian group of islands. [Illustration: North-eastern Siberia.] [Illustration: North-western Siberia.] While Anjou was surveying these islands, his friend Baron Wrangell was also occupied in exploration and research with his headquarters at Nijni Kolymsk. He made four sledge journeys over the Polar Sea from 1820 to 1823, in the _narti_ or dog sledges already mentioned. He considered March to be the best time of the year for travelling, because it is then easier work for the dogs. The dogs were fed on frozen herrings. The men wore reindeer-skin shirts, leather boots lined with fur, a fur cap, and reindeer-skin gloves. The party had a reindeer-skin conical tent, 12 feet across on the ground and 10 feet high, with a light framework of six poles. When they camped they lighted a fire in the centre of it, and were half smothered by the smoke. Each man slept on a bear-skin, and there was a reindeer-skin coverlet for every two. In his first journey Wrangell surveyed the coast from the mouth of the Kolyma eastward to Cape Chelagskoi, with the temperature sometimes as low as -31° Fahr. His second journey, starting on March 27th, 1821, was undertaken to see how far he could go over the ice to the northward, away from the Siberian coast. At a distance of two miles from the shore the party had to cross a chain of high and rugged hummocks five miles wide. Beyond, the ice was fairly level, but after advancing for 140 miles Wrangell found the ice to be weak and rotten owing to large patches of brine being lodged on the snow. It was therefore deemed prudent to commence their retreat on April 4th. They returned to Nijni Kolymsk on the 28th after an absence of 36 days, having travelled over 800 miles, averaging 22½ miles a day.