Agitation in this direction has led to the prohibition of ice cutting on specified polluted waters, by some boards of health, for any other than cooling purposes. In several States the ice crop is protected by the enactment of laws which make it a misdemeanor to destroy or injure ice in the field where it is to be cut. No doubt the preservation of the purity of our streams and lakes will receive more care in the future, as sanitary knowledge becomes more widely diffused. LAKES FED BY SPRINGS, and having clean beds, have naturally risen in value for ice cutting purposes. Running streams, especially those with a rapid current, purify their waters very rapidly. Exposure to light and air, the influence of oxygen, and the motion of the water, all assist in this good office. Foreign substances are expelled from the ice in the process of freezing, and streams of this character, not polluted by the presence of sewerage, waste products from factories, packing houses, gas works, etc., produce ice of great purity. THE OWNERSHIP OF ICE FIELDS has been a bone of contention in many instances, where a knowledge of the legal rights involved would have saved expensive litigation. In a general way, ice cutting rights are divided into two classes. Ice on navigable waters is under the authority of the national government. “Navigable,” in this instance, being used to denote tide water, the proprietary rights of owners of the abutting property are limited to the water line at high tides. On all such waters, navigation being closed, the ice is free and is secured by pre-emption, the first one to stake out claims being entitled to cut the ice. In contentions over boundaries of ice fields, where the issue is in doubt, the ice dealer whose property forms the water front is given the preference. Rivers, small lakes and navigable streams above tide water are termed public. The boundary line of abutting property is held to extend under the water to the center of the channel, and includes the ownership of the ice formed above it. Public convenience for navigation and commerce, however, take precedence. The rights to this ice are thus subject to contract and sale. The submerged land may also be sold, and all deeds to water front property should clearly set forth the boundary line and all the rights that are guarded and reserved. WHERE DAMS ARE BUILT across streams and the water line is raised on property beyond the limits of that held by the owner of the dam, consent must be obtained from the holders of property thus affected.