92.
Medicinal products from trees, 93, 95.
Metals, discovery of, 4-5.
Mica, in quartz sand, 58.
Migrations of birds, 205-206.
Migratory Bird Law, 200, 208.
Mills, the first, 7.
Mineral resources, destruction and new supply of, 49-50.
Mink, points against and in favor of, 193.
Mississippi Valley, rich prairies of, 53-54.
Mistletoe, an enemy of trees, 107.
Mocking bird, song of, 195.
Mongoose, as a pest, 153, 154.
Montenegro, results of destruction of soil in, 79.

National Forests, 133-139.
National Parks, 19, 139-143;
are game preserves, 204-205.
Nets, catching of fish in, 167, 169.
New England, soil of, 51-53;
gypsy and browntail moths in, 152;
beaver in, 179.
Newfoundland banks, fisheries of, 170.
Nitrogen, in soil, 57;
stored in soil by plants, 77.
Norway rat, 153.

Oil, waste connected with, 157-161.
Open season for hunting, 205.
Orange orchards, citrus canker in, 109.
Oregon, protection of beaver in, 179;
bird refuges in, 187.
Owens River aqueduct, 29.
Owls, good and bad points of, 190-191.
Oysters, raised on oyster farms, 167.

Palestine, destruction of vegetation in, 79.
Panama Canal, 87.
Passenger pigeon, extermination of,