"These lines mark the points reached by different explorers," explained the captain. "See, here is Scott's furthest south, and here the most recent advance into south polar regions, that of Sir Ernest Shackleton. In my opinion Shackleton might have reached his goal if he had used a motor sledge, capable of carrying heavy weights, and not placed his sole dependence on ponies."

The boys nodded; Frank had read the explorer's narrative and realized that what Captain Hazzard said was in all probability correct.

"It remains for your expedition to carry the Stars and Stripes further to the southward yet," exclaimed Frank, enthusiastically, as Captain Hazzard rolled up the map.

"Not only for us," smiled the captain; "we have a rival in the field."

"A rival expedition?" exclaimed Frank.

"Exactly. Some time this month a Japanese expedition under Lieutenant Saki is to set out from Yokahama for Wilkes Land.