Ever since "Robinson Crusoe" and "Swiss Family Robinson" were written cave
houses have been particularly attractive to boys; no doubt they were just
as attractive before these books were written, and that may be the reason
the books themselves are so popular; at any rate, when the author was a
small boy he was always searching for natural caves, or trying to dig them
for himself, and so were all of his companions. One of the most charming
features of the "Tom Sawyer" and "Huckleberry Finn" stories is that part
connected with the cave.
Fig. 155. Fig. 156. Fig. 157. Fig. 157.A. Fig. 157.B. Fig. 157.C.
Fig. 158. Fig. 159. Fig. 160. Fig. 161.
[Illustration: The original American boy's hogan or underground house.]