From the June 13, 1931, issue

TWIN ALBINO ROBINS HATCHED WITH NORMAL BIRD

Two albino robins, highly interesting and rather rare oddities in the bird world, have been watched from hatching to early maturity at the home of H.D. Shaw of Grinnell, Iowa, and had their pictures taken by Miss Cornelia Clarke, nature photographer.

The nest was built high up on the ledge of the porch where it wad sheltered and partly hidden by the vines, Miss Clarke writes. There were three eggs in the nest. Two hatched the albinos and the third an ordinary brown robin. The parents were normal in every respect except that the mother robin had two white tail feathers that were plainly visible when she was in flight. It is a curious circumstance that a white robin was seen near the Shaw home for several weeks the summer before the albinos were hatched.

ROCKS DISCLOSE THEIR AGES AFTER TREATMENT WITH ACID

Rocks that cannot be told apart as they are dug out of the ground can be made to disclose their ages and geological kinships by dissolving away most of their substance with hydrochloric acid and examining what is left under a low-power microscope. This method of analysis by insoluble residues has been developed by H.S. McQueen of the Missouri Bureau of Geology and Mines, working under the direction of Dr. H.A. Buehler, state geologist.

The development of the method was brought about by the presence of quantities of limestone rock from deep wells and other borings. All the samples looked pretty much alike, though it was known that they must be of very different natures and geologic ages. The masking similarity was due to the presence of the limestone matrix itself, in which there were none of the fossil casts that are the usual dating-tags that the geologist commonly uses in identifying his finds. Following hints given by earlier workers on the same problem, Mr. McQueen undertook to get rid of the featureless limy matrix by dissolving it in hydrochloric acid, so that he might concentrate his study on the bits of stuff buried in it that are not soluble in the acid.

TYPEWRITER FOUND NOISY AS STARTING ELECTRIC TRAIN

A typewriter makes as much noise as an electric train when it starts. This is one of the many interesting results obtained by A.H. Davis of the National Physical Laboratory, England, who has recently been making a study of noises. He compares loudness levels by the use of a tuning fork.

Mr. Davis has found that the noise inside the cabin of an airplane during flight is very much louder than that of an express train. An automobile horn is as loud as a subway train. Experiments in the first- and third-class compartments of a British train showed that the noise levels were the same when the windows were open, but when the windows were shut, the first-class compartment was the quieter.

Loud radio speech made as much noise as a railroad passenger car going at 35 miles an hour. A very noisy restaurant made the same amount of noise as a typewriter.

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