rudely shuttered
by a stick run through loops made out of wisps of grass. In hot weather,
the windows of the hutmay be loosely stuffed with grass, which, when
watered, makes the hut cooler.

Glass, to cut.--Glass cannot be cut with any certainty, without a
diamond; but it may be shaped and reduced to any size by gradually
chipping, or rather biting, away at its edges with a key, if the slit
between the wards of the key be just large enough to admit the pane of
glass easily.

[Sketch].

Substitutes for glass.--These are waxed or oiled paper or cloth, bladder,
fish-membranes, talc, and horn. (See "Horn.")

SLEEPING-BAGS.

Sleeping-bags.--Knapsack Bags.--These have been used for the last
twenty-five years by the French 'douaniers', who watch the
mountain-passes of the Pyrenean frontier. The bags are made of sheepskin,
with the wool inside. When not in use they are folded up and buckled with
five buckles into the shape of a somewhat bulky knapsack (p. 152), which
the recent occupant may shoulder and walk away with.

The accompanying sketches are drawn to scale. They were made from the
sleeping-bag belonging to a man 5 feet 6 inches in height; the scale
should therefore be lengthened for a taller person, but the breadth seems
ample. Its weight was exactly seven pounds. The douaniers post themselves
on watch more or less immersed in these bags. They lie out in wet and
snow, and find them impervious to both. When they sleep, they get quite
inside them, stuff their cloaks between their throats and the bag, and
let its flap cover their faces. It is easy enough for them to extricate
themselves; they can do so almost with a bound. The Spanish Custom-house
officers who watch the same frontier, use their cloaks and other wraps,
which are far more weighty, and far inferior in warmth and protection to
the bags. I described these knapsack bags in 'Vacation Tourists for
1860,' p. 449, and I subsequently had a macintosh bag lined with drugget,
made on the same principle. I had a hood to it, and also the means of
buttoning it loosely under my chin, to make myself watertight during
heavy rain. In that bag I passed many nights of very trying weather. On
one instance, I selected a hilltop in Switzerland, on the way from
Chambery to the Dent du Midi, during a violent and long-continued
thunderstorm. The storm began above my head, then slowly sank to my
level, and finally subsided below me. Many Alpine travellers, notably Mr.
Pa