Academicians

On photographic plates no bigger than a stick of chewing gum, astronomers can look at a spectrum so tiny that it must be viewed through a jeweler's eyepiece and tell what kind of atoms are dancing in a star trillions of miles away. Thus has astronomy advanced since Galileo first glimpsed the four big satellites of Jupiter and wondered what they were. The mod ern art of splitting up light into its com ponent colors, which disclose the chemical nature of the source, depends on a little thing called the diffraction grating. This is a plate of glass or metal with 15,000 to 30.000 parallel lines accurately ruled across every inch of it. Each line reflects the light at a slightly different angle. It was with diffraction gratings that science learned that electrons were waves as well as particles, that beams of light were particles as well as waves.

Even with diamond-pointed ruling machines it is extremely difficult to rule hundreds of thousands of such infinitesimal lines accurately on hard metal or glass. Last week at the Washington meeting of the National Academy of Sciences (see above), Physicist Robert Williams Wood of Johns Hopkins showed how a brilliant scientist may adapt for his own use a technique worked out for a wholly differ ent purpose. At California Institute of Technology, Dr. John Donovan Strong has been coating telescope mirrors with a thin, even layer of aluminum by placing the glass in a vacuum tank, boiling the aluminum off an electric coil so that the aluminum vapor deposits itself on the glass. At Johns Hopkins Dr. Wood used the same method for laying down on his plates first a thin coat of hard chromium, then a layer of soft aluminum. To make diffraction gratings the diamond point had to cut only through the aluminum skin. Last week Dr. Wood left no doubt that these gratings, with 210,000 lines in a space of seven inches, are the finest ever made.

One pest of spectroscopists is "ghosts" or false spectrum lines which appear because the grating is not absolutely perfect. In the Wood gratings the ghost lines are so reduced in strength that they are easy to identify and ignore.

Other highlights of the Academicians' meeting:

Apes. The Yale Laboratories of Primate Biology have a colony of about 40 chimpanzees which, because sexual and social experiments are constantly in progress, make frequent news. Last week Dr. Henry Wieghorst Nissen and Meredith P. Crawford ran off motion pictures showing altruism and co-operation among the apes. When one animal had food and another in an adjoining cage had none, the hungry one would beg by thrusting his hand through the bars. Often the other chimpanzee would share his food, especially if the two were well acquainted. Sometimes, however, the ape with food would simply shake hands with the other, or turn his back, or become so uncomfort able that he would retreat with the food to a distant corner.

As for cooperation, it was observed that two apes would soon learn to work together on a rope to bring a basket of food within reach. When one wanted to quit work, he patted the other on the back.

Dr. Robert Mearns Yerkes, director of the colony, gave the average menstrual cycle of chimpanzees as 35 days, the aver age pregnancy period as 236 days, slightly less than eight months. Said Dr. Yerkes : "The work we are now doing will shortly revolutionize inquiry into similar facts regarding human behavior. We shall dis cover that the facts discovered concerning the chimpanzee will be the same facts that we will discover concerning human beings. I will stake my reputation as a prophet on this prediction, and I invite you to ask me for an accounting of the situation three years hence."

Elephants. Dr. Francis Gano Benedict of the Nutrition Laboratory of the Carnegie Institution of Washington began his address thus: "It is impracticable to measure the rectal temperature of the elephant."

Dr. Benedict has accompanied circuses up & down the land in order to study the elephant. Zoologists would like to know what the normal temperature of an elephant is, while circus and zoo men would like to know when their charges have chills or fever. Dr. Benedict solved the problem by taking the temperature of excreta immediately after they left the elephant's body. He found that elephants were about two degrees cooler than humans. Average for 45 adult female Indian elephants was 96.6DEG, with a variation of about 1DEG. Dr. Benedict has found that the average elephant's heart beats only 30 times per minute. Elephants differ from other animals, including man, in that their pulse quickens when they lie down.

New Members. At Kitty Hawk, N. C. on Dec. 17, 1903, Orville Wright made the first flight in the plane that he and his brother Wilbur built. Because the Smithsonian Institution labeled the Dragon Fly, which was built but not flown by Samuel Pierpont Langley, as ''The First Machine Capable of Flight Carrying a Man," enraged Orville Wright sent the Kitty Hawk plane to the British Science Museum at South Kensington. Lately the Smithsonian has done everything it could to soothe Mr. Wright's feelings, promised that he could write his own label if the Smithsonian could only get the plane back from England. Last week, 33 years after Kitty Hawk, Orville Wright was elected a member of the National Academy of Sciences.

Fourteen other new members were elected, including Leo Hendrik Baekeland, inventor of Bakelite, and the University of California's William Francis Giauque, holder of the U. S. low-temperature record (.16 degrees above Absolute Zero).

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