VOX NOVA SCIENTIAE

25 years ago, with a little wooden hut  for a studio and the equipment of the day, an enthusiast began taking nature pictures. The result today is the formation of Gaumont  British Instructional, from whose library of classroom films the following excerpts are taken.  All these films are produced under the supervision of such well-known educational experts as  Dr. Julian S. Huxley, Biology; Professor Winifred Cullis, Physiology; Professor E. J.  Salisbury, Botany; Mr. R. A. Watson Watt, Physics; Dr. G. P. Gooch, History; and the Geography  Panel of the British Film Institute, Geography. First, The Plover, a film for quite young  pupils and a splendid example of the power of the camera in bringing nature into the  experience of even the town-bred child. The plover is a cautious bird and never  approaches her nest directly, but always in a zigzag manner so as to deceive any enemies  that may be watching. When she reaches her nest, we see it is rather a poor affair—just a slight  hole scratched in the meadow with a few pieces of dried grass thrown in. She looks around  very carefully before she finally settles. And now comes the job of arranging the  four eggs comfortably beneath her. As her mate is on guard overhead, she can  give all her attention to the job in hand. And it takes a lot of fidgeting  and pushing the eggs with her bill. And when she has got them  settled all right in front, they have got underneath her feet at the back. And now a cutting from a hygiene film: Circulation. An object lesson in the use  of the diagram for educational pictures. To see more easily how it all goes, let us  look first at one side of the heart only. The arrows indicate the blood flowing from  the veins into the left side of the heart. The auricle is now contracting and emptying  its blood into the lower part of the ventricle. The ventricle contracts and the blood tries  to go back into the relaxing auricle but is stopped by the valves, which open up like  an umbrella. The ventricles contract and force the blood out into the artery.  Cup-shaped valves prevent the blood from going back into the heart. Now watch this  happening on both sides at once. And remember, blood comes into the heart from the veins and  is pumped out from the heart into the arteries. Look at the real heart beating. The movement  you can see is made up of the contraction of the auricles at the top of the heart  and of the ventricles at the bottom. This time let us show what the speeding up of  growth can do for us in the field of botany. In this diagram is one grain of pollen from the stamens of one thistle floret left on  the inside of the stigma of another. Now the pollen puts out a tube which grows  down the style. In real life it goes much more slowly than this. The pollen tube grows  down and penetrates the ovule inside the ovary. The contents of the pollen grain unite with  those of the ovule and enable it to develop into a seed. The ripened ovary is then  called a fruit. While this is happening, the flower head has faded, petals and  stamens have died, and the down is growing. Each ring of down has developed from one  floret and is still attached to a fruit. The down gradually grows until, on a dry  day, it spreads right out like a parachute and pulls the fruit away from the flower head.  If you watch, you can see this taking place. And now to a film for advanced students:  The Cathode Ray Oscillograph. Note how the perfectly timed commentary merely directs the  attention. These are the main features of the cathode ray oscillograph. Cathode ray is  the name given to the beam of electrons, and it is the most nimble  indicator that can be devised. But there is still one great drawback.  We cannot see it except in the dark. To get over that difficulty, the end of the tube is  coated on the inside with a chemical which glows when the beam strikes it. We also fix a screen  so that the eye can concentrate on the tube. Here is the spot of light  formed by the beam striking the chemical. And as the beam moves  up or down, so the spot moves also. If we connect the plates to a very slowly  alternating current, this is what happens. And when the frequency increases, you  get the effect of a line of light. So, here is a third indicator to try  out against the needle and the mirror. Out goes the needle, but the other two keep on. We are nearing the limit of the mirror  galvanometer. It is beginning to fail. It is gone. The cathode tube, you see, remains unperturbed  even by a frequency of 10,000 cycles per second. We can take it further still— as far as 100,000 cycles per second, and still it keeps on, and will keep on  at frequencies far higher than this. By eliminating weight almost entirely, we have  at last got an indicator which will follow electrical changes at a speed to satisfy the  almost fantastic demands of radio research. Next is a section from Coal, a regional  geography film of the coal lands of the Midlands. This section deals with shot firing. The first operation is to drill a hole in the  coal face with an electric drill. They are going to make an  explosion in that hole. So all inflammable coal dust has to be cleaned out. Next, the man in charge makes a test for the  presence of gas. This gas is called firedamp, and it was formed when the coal itself  was formed millions of years ago. It is a high explosive and terribly dangerous.  In this case, there is no gas about, so he makes up the charge by pushing an  electric detonator into the powder cartridge. He puts it into the hole with  the detonator wires hanging out. Then he rams a mixture of sand and clay hard  into the hole. By this means, the charge will be prevented from blowing straight out, and the  effect of the explosion will be spread through the coal all around it. Then he couples up  his electric cable to the detonator wires. “I’m ready for firing now, Jim.” “Clear off up the face.” “I’m ready, Blanty.” “Clear off into the gate. I’m following you.” He has left the cable fastened to the  detonator wires and it runs along the face looped up out of harm’s way. He has the  other end, which he fastens to the exploder. Ready— Fire! Here is a selection which demonstrates how  the camera can show correct methods in sport, observable by no other means. The crawl  is the fastest of all strokes in swimming. Note particularly how breath is taken  and exhaled. Every complete stroke, and always on the same side, the head  is turned just sufficiently to bring the mouth above the waterline. Then a breath  is snatched. Exhaling is done underwater. Here is a common fault in connection with  breathing. Instead of just turning his head for breath, this swimmer is rolling his  whole body. This causes loss of speed. Look at this leg action. The hands are  purposely not doing the correct stroke. Note how every third beat is a deep  one. One, two, three, four, five, six. Notice there is no stiffness in the limb, especially at the knee and ankle.  The heels just break the surface. Finally, a scene from one of the physical  education films illustrating the Board of Education syllabus and made primarily for  teachers by a British Film Institute committee. A rhythmic trunk bending sideways. Hips still.  Bend well over. Bend straight to the side. Not forward like this. Or leaning back like this. But straight to the side. Shoulders square  to the front. Feet firm and knees straight. The bend should be here. Over, over, over, over. Exercises taken with a rhythmical swing  must be well-timed, free, purposeful. And now the door has closed upon your view of the  selection from an extensive library of educational films. You can obtain all details both of films  and portable equipment from GB Equipments Limited.