The teeth catch in the snow or ice, and since the cylinder is heated by the exhaust steam, it melts and packs the snow for the trucks following it.

The drum is six feet in diameter, with walls an inch and a half thick, and it weighs seven tons.

It is used in all sorts of places where horses cannot go, as in swamps, and by substituting wheels for runners it has even been used on sand.
In the Canadian lakes there has been devised a queer creature called an "alligator," a small and heavily equipped vessel for hauling the logs thru the lakes.

When its operations in one lake are finished, a wire cable is taken ashore and made fast to some tree or other safe anchorage, the capstan on its forward deck is revolved by steam and the "alligator" hauls itself out of the water across lots to the next lake and begins work there.
The greatest improvement in water transportation is the giant raft, Fig.30.When such a raft is made up, logs of uniform length are placed together, the width of the raft being from sixty to one hundred feet and its length, one thousand feet or more.

It may contain a million board feet of timber.