"We might heave 'em overboard some night," suggested Loggermore, but the other sailor would not listen to this proposal. He was willing to have the youths left behind, but that was as far as he cared to go. "Never mind, we can watch them at Upernivik," said the tar. "There will be a better chance to leave them behind there than there was here." And with this proposal the affair rested, although Loggermore declared that if there was any more killing of birds from the ship he would heave the boys overboard sure. This may seem a terrible threat to some of my readers, but they must remember that some sailors, especially ignorant ones, are extremely superstitious, and they deem the killing of a bird at sea the worst kind of a bad omen. The run up the Greenland coast was made without unusual incident. They passed a number of icebergs, but always at a distance, and the small ice did not bother them seriously. The weather moderated a little, so that life on deck proved delightful. The boys saw more wild geese, some ducks, and also some northern petrel, but, warned by Captain Williamson, did no more shooting. "Upernivik is about the last settlement north of any importance," said Professor Jeffer to the boys. "It can be called the most northern town in the world. It is a trading station for the Esquimaux, and also has a mine, from which large quantities of cryolite are obtained." "And what is cryolite?" asked Chet, curiously. The professor smiled faintly. "It is a substance, found only in Greenland, from which washing soda is made, and also some kinds of baking powder. The metal, aluminum, is obtained from it, and it is also used in the making of certain kinds of glass. Greenland has a very large stratum or deposit of cryolite, and it is a source of considerable revenue to the mine owners, and also to the Danish government, the latter putting a heavy export tax on it." It was nightfall when the steamer dropped anchor in the harbor of Upernivik. From the deck of the vessel Barwell Dawson, who had visited the settlement before, pointed out the governor's house, the Moravian church, and other buildings. "There are quite a number of Esquimaux here, full-blooded and half-breeds," said he. "Most of them live in the stone huts along the mountain side." "What do you mean by half-breeds?" questioned Andy. "The half-breeds are the families of the Danish men who have married Esquimaux women," replied the explorer. "Some of the half-breeds are very intelligent, and they are also much cleaner than the full-blooded Esquimaux." "Are the Esquimaux very dirty?" asked Chet. "They are the dirtiest people on earth," was the emphatic answer. "And why shouldn't they be? They never wash, and the only thing they rub on their bodies is whale or seal oil, to keep out the cold and to help limber them up." "Gracious! I shouldn't want to live in the same house with them!" cried Andy.