From the March 18, 1933, issue


The photographer for the U.S. Bureau of Reclamation has caught the spirit of the beginnings of Hoover dam in the picture reproduced on the front cover of this week’s Science News Letter.

He was looking upstream toward the dam site when he snapped his camera. The structure will rise beneath the cables, which appear as dim streaks stretching from rim to rim of the canyon in the background. The dry ground in the bed of the river before the cables is the cofferdam and rock barrier built to keep the water from backing up to where actual construction is going on.

Another cofferdam out of sight farther up the river turns water into the four diversion tunnels whose outlets are seen in this picture.

The pouring of concrete on the dam proper is scheduled to begin July 1, 1933, and end April 1, 1936.


Fingerprints to protect checks against forgery and theft.

This is seen as a possible outgrowth of the present banking situation if the proposal to expand the U.S. Postal Savings System to provide for checking accounts becomes a reality.

Fingerprints are required of all depositors and those withdrawing money from postal-savings depositories in the larger post offices today.

When you open your account and make your first deposit, your fingerprint is taken and filed with a description of you and other identifying material in that post office. To withdraw your money, you must go in person to that same post office and again have your fingerprint taken. If the fingerprints are identical, you get your money. But the forger or thief, if he should have the boldness to submit to the fingerprinting process, would betray his false identity.

If fingerprints were required on all checks, this would serve as practically a positive guaranty against forgery. For your fingerprint is your own personal property and unlike that of any other individual in the world. Even the fingerprints of identical twins differ enough that they can be distinguished.


“Cooperative phenomena” is a new term introduced into physics by Dr. F. Zwicky of the California Institute of Technology to designate what happens when a great number of elementary particles, such as electrons and atoms, interact.

Cooperative phenomena would explain the existence of crystals, Dr. Zwicky believes.

Four groups of problems in modern physics are listed by Dr. Zwicky in the Physical Review:
“(1) The problem of the nuclei of atoms and the existence of elementary particles such as the proton, the electron and the photon; (2) the problem of the interaction of the electromagnetic and the gravitational fields with matter and the problem of unifying the fields; (3) the problem of the universe as a whole; (4) the problem of cooperative actions of a great number of elementary particles, and, in particular, the problem of the solid state.”

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