INSTRUMENTATION by Ralph H. Müller
Space conquest plans overshadow needs for research on terrestrial problems
THESE are times which the sober scientist will view with growing apprehension, as he hears the screaming sirens and watches the antics of the bucket brigades. Temporarily, we are in the hardware versus ideas stage. In any crisis, men of action and authority are prone to favor the hardware and relegate scholarly inquiry to later and more serene times. To men of action, a crisis is a delightful challenge; they even come to regard a succession of crises as a legitimate way of political life. This is abhorrent to any scientist, who well knows that the progress of science is a continuous, orderly, and intricately interwoven series of developments. There are bright spots, rare flashes of intuition, brilliant discoveries which only serve to maintain the excitement and drive for further knowledge. It is curious what people will do under stress, and nations often reflect individual behavior, presumably at the level of the least common denominator. It is not trivial to recall Rex Beach's hilarious account in "The Ne'er Do Well." In a small Central American town, the frenzied occupant of a burning house threw a phonograph out of the fourth story window and then carefully lowered a mattress to safety with a rope! There is little doubt that we shall get the hardware. Congress can be expected to vote large sums to regain our stature in the rocket, missile, and satellite race. The long-range, and far more important question, is the support which will be given to pure research and education. Our own guess is 5% or less, of the total. That is the present figure for pure research out of our total expenditures for all research and development. When the fire hoses are out, there is little time for tea and cakes. It's a sad fact, but we are now committed to the conquest of space. We must get to the moon. I t is bleak and barren, with enormous ranges of temperature and with an environment wholly unsuited for human habitation.
"All the more challenging," say the enthusiasts, "we'll take everything we need with us in space ships." Perhaps we should get on with it as soon as possible. Then after having fitted out the moon with filling stations, hamburger stands, and a decent complement of neon lamps, we can get back to the solution of some important terrestial problems. Perhaps common courtesy would prompt us to leave the moon to the Soviets. In many respects it would be a comfortable haven for the ordinary Russian citizen. Highway Illumination. We might, after such a triumph, feel ourselves capable of solving the problem of highway illumination, unless the problem has already been taken over by the American Institute for the Blind. We realize that the principles of scientific highway illumination are covered completely in the 1915 edition of the Electrical Engineer's Handbook, but there might be a few new angles. At present, two blinding spots of light signify that a motor car is behind them. If only one appears, it is a motorcycle, or again a motor car with one burned-out headlight. A revolution might be achieved by illuminating the highway instead of the motorist. Why not illuminate the vehicle itself, say by softly luminous plastic bodies? Fluorescent markers have been a tremendous boon, but why not extend the principle? Is it impossible to incorporate millions of cheap fluorescent buttons in concrete or macadam? Or can a luminescent concrete or paving be developed? There are infinite possibilities in the excitation of such luminous markers. Subchassis ultraviolet lamps could do this. And what about the very appreciable static charges developed by every rubber-tired moving vehicle? We know how to get rid of them by dragging a chain, but no one seems to put them to use. We are very expert in solving transportation problems by ordinances, penalties, and fines, but progress continues to be derived from the handbooks.
A great deal is known about the excitation of phosphors and their decay constants. An automatic count of traffic on a specified highway could furnish the data for the number, nature, and disposition of phosphorescent markers and their frequency of illumination by passing cars to maintain an acceptable level of soft illumination. The light from Arcturus was harnessed to open the gates at the Chicago World's Fair of 1933-34—a neat trick and historically significant, because the light had left Arcturus at the time of the Columbian Exposition in 1893. Shall we have to express technical advancement in light years? Communication. We might even find scientific means of expediting mail delivery. It's becoming a standard American sport to poke fun at the transient and unstable French governments, but rest assured—the best French administration which could possibly be assembled could be toppled in 48 hours if the Parisian did not get his five mail deliveries a day, or if he could not have his guaranteed 1-hour delivery anywhere in Paris by the beloved pneumatique. Anyone here old enough to remember two and three deliveries a day? The contrast between this mode of communication and the telephone illustrates the important and fundamental difference between the bureaucratic and the scientific approach. In our humble opinion, the telephone system is the most courteous, competent, and efficient business enterprise in our nation. The reason is not hard to find. It is not merely a matter of good administration, shrewd public relations, and sound finance, but the large and impressive amount of fundamental research which has characterized this enterprise from its very beginning. They even publish their own scientific journal and it is one of the world's most respected repositories of fundamental research. Small wonder that four of its staff members have been Nobel Laureates in physics. VOL. 30, NO. 2, FEBRUARY 1958
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INSTRUMENTATION
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TAYLOR COMPARATORS for FAST, ACCURATE
pH, CHLORINE, PHOSPHATE TESTS to insure precise control
Taylor Comparators allow you t o make fast, accurate colorimetric tests for p H , chlorine, phosphate or nitrates, etc. right on the spot. In a matter of minutes you get correct operational data to help you determine the exact amounts of chemicals needed t o properly control crystallization, bleaching, precipitation, extraction or waste treatment. To use, simply fill the middle tube with treated sample, move color standard slide across until sample matches one of the standards. Values are then read directly from the slide. Taylor Comparators are durable, lightweight, portable. Many serve for several determinations with only a change of color standard slides.
COLOR STANDARDS GUARANTEED Be sure to use only Taylor reagents and accessories with Taylor Comparators to assure accurate results. All Taylor liquid color standards carry an unlimited guarantee against fading. SEE Y O U R DEALER f o r T a y l o r sets or i m m e d i a t e replacement o f supplies. W r i t e direct f o r FREE H A N D B O O K " M o d e r n p H a n d Chlorine C o n t r o l " . Gives theory a n d a p p l i c a t i o n o f pH control. Illustrates a n d describes complete T a y l o r line.
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ANALYTICAL
CHEMISTRY
For years we have been collecting items for a comprehensive compendium on what might be entitled "The Decline in the Art of Communication." After reading some of Shannon's recent papers on the entropy of information, it was a shattering experience to encounter a nine-year-old who could not decipher the label on a ketchup bottle! It was not the benzoate of soda item which threw him—that is technical; it was the small words. This lad is not a moron or congenital idiot; he has mastered American Mandarin, the idiography of word pictures. He has no trouble with television, in which the message is visual and audio, and where the intellectual level is pitched two years below his age group. We have a theorem which states that the picture size of a television screen is inversely proportional to the number of books in the household. Try this out on your friends; we would like to evaluate the constants in the equation. I t is a simple matter to normalize the curve, at one end at least. If it is the home of a serious scholar, with more books than the shelves can hold, the chances are ten to one he doesn't own a television set. Some of our instrument-minded people will be highly elated at the prodigious orders for hardware which will appear very shortly. The conquest of space, in all its phases, requires lots of very elegant and costly instruments. For our part, we keep thinking about the man in pure research who can afford very few of these things. There is a tantalizing difference between what we could use and what we can afford. Perhaps it is a salutory thing after all. Our European friends never cease to wonder at and admire the equipment in American laboratories, but even in a charitable and friendly spirit they have been known to wonder whether our pure research efforts are comparable to the funds which are expended. After all, we can dream and continue to watch the assembled committees and await their solemn deliberations. We shall, without doubt, be on our way to the moon very soon. As far as we are concerned—just drop us off in London or Paris, if you don't mind. Tetrode Power Transistor
The use of transistors in instruments is increasing rapidly. Great advances in transistor design have helped in these applications. A new power tetrode resistor has just appeared. I t gives low audio distortion, high efficiency, and high power output with high impedance drive and without feedback. The Honeywell H200E Tetrode power transistor has two separate base
connections which permit control of the device characteristics. In addition to improved linearity, the frequency response is 50% greater than triode transistors. Thermal stabilization of the power tetrode can be achieved more easily than with triode transistors because of the second base connection. It permits high temperature operation of direct coupled circuits using power transistors. The H200E is a germanium P N P alloyed junction power transistor designed to operate on 28volt systems with currents up to 10 amperes. Its thermal resistance is less than 1° C. per watt. Complete information on this device is available from Honeywell, Dept. PI-10-262, Minneapolis, 8, Minn. An example of a recent transistorized instrument is given by C. W. Hargens of the Franklin Institute [Rev. Sci. Instr. 28, 921 (1957)]. He describes a portable liquid density instrument employing transistors. This instrument is the electromechanical equivalent of a sensitive hydrometer. The range of density is 0.8000 to 1.0000 and can be extended without impairing the accuracy. Temperature-controlled samples of 100 cc. are required. A glass bulb with a thin spindle is spring-suspended in the liquid to be measured. The top of the spindle carries a soft-iron core which moves inside a linear differential transformer. The signal from this transformer is detected by a multistage transistor amplifier followed by a phasesensitive detector and a zero center 0-30 microammeter. The object is to bring the system to null indication, which means that the hydrometer float must be brought to a null position within the transformer core. This is achieved by passing a measured current through a coil attached to the spindle. The coil is mounted in a homogeneous, steady magnetic field. It is this current which is a measure of the density. The L. D. transformer system which detects the balance point is very sensitive. A half-inch deflection on the output meter corresponds to a change in density of 0.0001 or ±10 microinches displacement of the spindle. The precision is about 1 part in 2000. The L. D. transformer is excited at 8 kc. by a transistor oscillator. A Zener-stabilized transistor power supply is used to supply current to the restoring coil. It will be recalled that the magnetically controlled float has been used for many years in precise determinations of density. The present instrument is a modern, compact version of that principle.
