Catching Up With Nature


By C. F. KETTERING, Vice President, General Motors

Broadcast over the N.B.& Network, July 30, 1944

Vital Speeches of the Day, Vol. X, pp. 736.

RECENTLY, Dr. Black conducted on the General Motors' Symphony, the overture by Johann Strauss "Die Fledermaus" or "The Bat." I have often wondered if the composer knew at the time he wrote this that the bat had a voice of great range. The voice however is pitched mostly above the ability of the human ear to detect. - I was discussing this with a musical friend of mine and I asked him if he knew of this peculiarity. He said he never heard of it but he was very curious to know why the bat had this high pitched voice and how he used it. So I told him of the work that had been done by two professors at Harvard and added that there were other animals such as cats and dogs who, in addition to their audible voices, were able to communicate with each other in inaudible sounds.

Now most people regard the bat as a rather objectionable, somewhat loathsome creature that lives in dark caves and comes out only in the evening and flies around to hunt for food. The thing that makes this more interesting is that tests made in many of the caves where the bats live show that there is insufficient light to register on our most delicate apparatus. These devices can detect light much below the point of visibility. Now the bat can fly around in these caves apparently as well as if they were fully lighted.

This uncanny "blind flying" ability has, from time to time, aroused a lot of speculation on the part of scientists. Comparatively recently, as I mentioned, two men at Harvard found what they believe to be the answer. Instead of theorizing they decided to try a few simple experiments.

The two men, Dr. Galambos and Dr. Griffin, picked out a sound-proof room for their experiments and suspended from floor to ceiling a straight row of steel wires spaced one foot apart. Bats were set free in the room and they flew about, rarely touching the wires. Then they were blindfolded and this did not seem to make much difference, in fact, some of the bats did better blindfolded. But the next step indicated the bats' secret. Their ears were plugged and their eyes were left uncovered. It was very difficult now to make them fly but when they did they collided consistently with the wires. And the same thing happened when a thread was tied around their mouths and their eyes were uncovered and the ears unplugged. Apparently the bat steered by sounds from its mouth which were picked up by his ears—the eyes had little or nothing to do with it.

Using the most modern sound recording devices the men found that while in flight the bat emits a sound which has a frequency of vibration reaching a maximum of about 80,000 cycles—or, in musical terms, about 8 1/2 octaves above middle "C." We call these sounds "supersonic" because their pitch is so high they cannot be heard by the human ear. Our range of hearing is somewhat greater than the highest note produced by instruments of the orchestra. The harmonics on the E string of the violin are about 10,000 cycles per second. Apparently, the bat while in flight sends out these inaudible sounds in short squeaks which strike the obstacle he is approaching and are reflected back and are picked up by his sensitive ears in time for him to steer clear of the object.

This method of sound reflection has been used for many years to determine the depths of the ocean and the pilots of boats in Alaskan waters often use the echo of their boat whistles to determine if they are getting too near the cliffs when travelling in dense fog. Many other applications of this system are in daily use in laboratories for determining faults in materials and undoubtedly after the war it will be applied in many other ways.

We feel proud of our recently developed sound echo devices even though the bat has been using it in the dark for thousands of years. We marvel at the automatic flying instrumentation of our modern airplanes but every year flocks of birds go from their southern homes to their northern ones and return to precisely the same location with only their natural "instrumentation." Man has attempted to duplicate some of the feats of the animal world and in recent years science has given us instrumentation that has done very well indeed.

But we are a long way from catching up to Nature. There are some people who speak glibly of science "conquering Nature." Nothing could be further from the truth. When a scientist conquers something, he abides by the fundamental laws and does so with Natures permission. He has learned that conquering is submission.