The East Linthorpe Literary, Philosophical, and Debating Society, October, 1994


"Have any of you noticed the puzzling advice on saving water that is being offered at present?" The Author looked around the company but received no response. "We are told that taking a shower instead of a bath uses less water."

"Nothing puzzling about that, surely?" The Mathematician's tone was somewhat dismissive.

"There is when you take it in conjunction with the admonition from the same sources that on no account should one wash dishes under running water because it is wasteful. I am accustomed to smart computers, but can anyone tell me how the water system knows whether it is a person or a saucepan for which it is dispensing water, so that it can adjust the flow to make running water more economical for the former, and less economical for the latter?"

"The advice was probably compiled by the same experts that pontificate upon conserving heat," the Physicist suggested. "You will no doubt have noticed that for houses with solid glass windows they advocate double glazing, on the grounds that the space between the glass has insulating properties, but for houses with cavity walls they advise filling the cavity on the grounds that the airspace has poor insulating properties. Many a house-owner has simultaneously eliminated the spaces from his walls and created them in his windows without querying the self-contradiction involved."

"There is of course an obvious commercial advantage in persuading people that whatever they already have needs to be changed," said the Philosopher. "It is surely no coincidence that last year's vendors of draught-proofing are this year's advertisers of ventilation systems."

"A profit motive is not necessary," the Author said. "It is typical of soi-disant experts to believe that whatever already exists is inferior to something that they can devise. Those who practise the arcane arts of Organisation and Methods will always, if they are wise, first ascertain whether the subject of their assignment has ever been surveyed by their department before. If they fail to take this elementary precaution, the odds are high that they will end up recommending that the present methods be replaced by the original system that their predecessors abolished."

Several pairs of eyes were turned towards me, in the knowledge that I was formerly employed in that field, but I was too engrossed in memorising the appearance of the toecap of my left boot to be drawn into the discussion, although the Author's comment had, in truth, revived certain embarrassing memories.

"The second-hand experts of the Press are the worst of all," opined the Physicist. "There is scarcely a scientific theory that they have not grossly misrepresented in order to justify their quest for an interesting story. Take, for instance, the matter of streamlining. In physics, the word streamline has an exact technical meaning."

"Namely?" queried the Philosopher.

"If you insist," replied the Physicist, with the trace of a smile. "A streamline is a line in a fluid such that the tangent to it at every point is in the direction of the velocity of the fluid particle at that point at the instant under consideration. When the motion of the fluid is such that, at any instant, continuous streamlines can be drawn through the whole length of its course, the fluid is said to be in streamline flow. If the word streamlined were used only by those who understood what it meant, it would not have achieved the currency it now enjoys. In the thirties, however, it was taken up by journalists, particularly motoring correpondents, and given a completely new, but false, identity. The misinformation that they retailed actually influenced the shape of motorcars for twenty or so years."

"You may recall the sort of vehicle to which I refer, shaped so as to be bulbously round at the front, and tapering to a point at the back. Two myths were created in respect of this shape. The first was that it reduced air resistance because the leading edge of the shape parted the air cleanly, while the pointed rear end allowed the separated air flows to reunite behind the vehicle with the minimum of turbulence. Many a diagram showing little arrows flowing round such a shape graced the pages of the technical press in demonstration of this thesis. The second myth was more homely. It was observed that this was the very shape adopted by a drop of water falling through the air, thus implying that nature confirmed that this was the ideal shape to penetrate the atmosphere."

streamlined car

"There are two things wrong with this. The first is that there is absolutely no reason to suppose that a drop of water falling through the air will adopt the best shape for penetration. If you wished to design a good shape for a masonry nail, for example, would you take a lump of clay, throw it against a wall, and then declare There, that is the shape the clay assumed in order to penetrate the wall, therefore it is the ideal shape for a masonry nail ? Of course not. The shape assumed by the clay represents the triumph of the wall over the clay, not vice versa, and precisely the same applies to the shape assumed by a drop of falling water. The second error is one of fact: a drop of water falling through the air does not assume the suggested shape."

drip(1)

"But the shape you describe is usually supposed to be the shape of a falling drop of water," protested the Author. "Is it not generally known as a tear-drop?"

"Indeed," replied the Physicist, "but only because our observations are mostly of a drop at the start of its fall, when it may well have that shape. Our unaided eyesight is not quick enough to note what becomes of that shape as the drop accelerates. Let me describe to you what a series of stop-motion photographs would show of a drip from a high tap.

As the water slowly collects, it clings tenaciously to the spout of the tap, surface tension holding it together. As it gets larger, gravity pulls the bulk of it downwards, but still it clings to the spout above. Its reluctance to let go draws out the tail behind the drop. As the drop gets heavier, so the tail is extended more and more, until eventually it breaks, and the drop starts to fall freely.

As soon as this occurs, the part of the tail that was left on the tap retracts, surface tension pulling it into a more compact shape once it is relieved of the weight of the drop. Likewise, the tail attached to the drop also gradually retracts. Surface tension tends to pull the drop into a shape that would have the smallest surface area for its volume, namely a sphere. However, air resistance also has its effect upon the drop as it falls, not dissimilar to the effect of the wall on the clay. The sphere becomes an increasingly oblate spheroid, and probably will eventually start to disintegrate."

"In the 1950's, even racing cars were still being designed according to such fallacious principles. I recall the astonishment when John Cooper produced the first scientifically shaped racing car. The Cooper-Climax was unconventional in almost every respect. It did not look 'futuristic'. Its engine was taken from a forklift truck, and mounted at the rear of the car. Unlike the pre-war rear-engined Auto-Unions, the Cooper had only vestigial front bodywork, and was uncompromisingly flat at the back. It would have been laughed off the circuits but for one circumstance — it went faster than all its rivals, and won race after race after race. The streamline theory never recovered from this conclusive disproof by demonstration."

"The conclusion I draw from this," the Author intervened, "is that, when used in a non-technical sense, the most appropriate meaning for the verb to streamline is:

to modify in such a way as to suggest efficiency to the ignorant, whilst impairing performance in reality.
This definition is of particular interest because streamlining persisted in the vocabulary of one profession long after motoring correspondents were shamed into abandoning it. I refer, of course, once again to the efficiency experts of Organisation and Methods, whose reports abound with claims that their proposals will 'streamline procedures,' claims which I am prepared to endorse so long as my definition is understood to apply."

Whether anything further transpired on that occasion, I am unable to report, as I had slid out of the door before the Author finished speaking, and was on my way home to enjoy the sympathetic company of my cats.