AS THE FISH SEE IT

The picture on the cover of this week's SCIENCE NEWS-LETTER is an artist's idea of the apparition that must frequently startle the small fish in the shallow water among the mangrove roots around the seaward edges of Florida. When the water surface is thrown into ripples, it is as impossible to see up out of it as it is to see down into it, so that the bird's feet and his great, hump-beaked head appear as correlated but disjunct phenomena.

The painting is by Wilfrid Swancourt Bronson; photo by courtesy of the Buffalo Museum of Science.

FATAL GAS USED IN FEW REFRIGERATORS

Deaths as a result of gas leaks from automatic refrigerators, such as occurred in Chicago recently, are unlikely to be repeated very extensively elsewhere, in the opinion of government experts. Of 63 makes of electric and automatic refrigerators compiled in a recent list, only 23 make use of methyl chloride, the gas responsible for the Chicago fatalities, as a refrigerant. Of these, only one is a nationally advertised make. Furthermore, the only danger comes from central refrigerating plants, used in apartment houses, where the refrigerant is piped to a number of cold boxes throughout the building. Even when methyl chloride is used in a small independent home unit, a leak would not liberate enough of the gas to cause danger.

Sulphur dioxide, the choking gas that results from the burning of sulphur, is the most popular cooling compound, and is employed in the two most widely used electric refrigerators. While this is irritating to the nasal passages, it is not really poisonous, in the same sense as the poison gases used during the war. Its pungent smell is recognized before it reaches dangerous concentrations. Ammonia, used in many refrigerators, is safe for the same reason.

Methyl chloride is odorless, and, while it is not poisonous in itself, a large concentration would exclude the necessary oxygen, and death would result if a person were kept in a closed room with it. Many manufacturers use it in combination with either ammonia or sulphur dioxide, which have characteristic odors that reveal leaks. For a similar reason, manufacturers of illuminating gas, which consists largely of odorless and poisonous carbon monoxide, mix other gases with it that give the characteristic odor. One manufacturer of refrigerators makes use of ethyl chloride, which is not poisonous but is highly inflammable. Attempts have been made to mix methyl bromide with it to lessen the fire danger, but methyl bromide is truly poisonous.

Carbon dioxide, which makes up a large percentage of our very breath, is used in one make of refrigerator. This is also the refrigerant used in cooling systems of battleships.

SWEETER MILK SUGAR MADE COMMERCIALLY

A form of milk sugar, called beta lactose, sufficiently sweet to be used as a table sugar, is about to be produced commercially through the efforts of Dr. John Harvey Kellogg, direct of the Battle Creek Sanitarium.

The usual form of lactose is a chalk-like, slightly sweet powder that is difficult to consume in quantity. Since milk sugar is sometimes used therapeutically as a substitute for ordinary table sugar, chemically known as sucrose, the production of a form of lactose three times as sweet and three times as soluble as commercial lactose is likely to prove of value to medical practice. Patients will be able to substitute the beta lactose for the common sucrose of the table and this milk sugar will be taken as a food rather than an unpalatable medicine. It is about a third as sweet as ordinary sugar and will cost about fifteen to twenty times as much per pound.

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