Tom B. Allen works for the National Geographic Society's book division. He has recently been updating the Geographic's "We Americans" for its third printing. Geographic publications are known not only for their remarkable color photographs but also for the care with which the accompanying text is researched.

When "We Americans" was first published in 1975, one sentence in it said, "Through the 1890's safety bicycles sold for an average of $100 to $125, the rough equivalent of $575 to $725 today." When Tom checked on what that rough equivalent would be today, he learned that in six short years it had leaped to "$800 to $1,000."

Of course, this will come as no surprise to anybody who read the Metro story headed "Ten Years of Inflation" in Sunday's Washington Post. Staff writers Molly Sinclair and Saundra Saperstein packed the essence of their report into their very first paragraph. It said: "Workers in the Washington area must earn more than twice as much today as they did in 1971 to have kept up with inflation -- and most of them don't even come close."

Graphics alongside the story gave 10 categories of wage-earners, from garbage collectors to congressmen, an opportunity to compare the average wage for their kind of work in 1971 to the average of 1981, and then to compare their own 1981 wages to the number of dollars they ought to be earning today just to retain the purchasing power they had 10 years ago.

In only two of the 10 categories (lawyers and letter carriers) did wages go up faster than inflation, and in one (supermarket cashiers) wages were within a whisker of rising at the exact rate of inflation. In the other seven categories, the real purchasing power of the wage-earner fell, sometimes by a substantial margin. The biggest losers have been congressmen, who made $42,500 in 1971, make $60,663 in 1981, and would need $90,355 just to get back what they've lost.

I understand why it is necessary to offer good wages to congressmen and to top managers in government, but I am not sure I am prepared to shed my tears for congressmen who lost purchasing power because of an inflation they helped create. However, I do have to question a scale of values that rates a supermarket cashier (union member) at $19,718, a policeman with 10 years of experience at $20,875, a postman with seven years in service at $20,460, a Montgomery County teacher with a master's degree at $22,873, a GS 11 accountant at $25,861, a union electrician at $28,184 and a law graduate just starting his career with a major law firm at $34,000.

The three things these people have in common with nurses, bus drivers, short order cooks and reporters is that they all want more; they do not agree about how much people in other lines of work are worth; and they don't much care. They are more inclined to form themselves into political pressure groups to protect their own turf than somebody else's.

It would avail us nothing to argue whether a teacher is worth twice as much as an electrician, or half as much, or the same amount. Wages are not set according to concepts of right or justice.

Wages are set in an open competition in which everybody demands more but some people don't have the muscle to get more. It is not a good system, but I don't know of an alternative that does not begin with the promise that Big Brother is wise enough and fair enough to set wage rates by decree.

I don't like that alternative. Big Brother might have a low opinion of reporters. POSTSCRIPT

While I was recuperating from that minor surgery, I watched the start of a professional basketball game. After the players had been introduced, the public-address announcer invited everybody in the arena to "join in singing the national anthem."

As the camera panned around the auditorium, it struck me that many spectators were singing, but only two mouths were moving among the players and coaches on the two teams. One man appeared to be singing, the other was chatting with a teammate.

That is not a very good showing for a group in which an average man is paid more for playing one game than a teacher with a master's degree is paid for working a whole month. One who makes $500,000 a year, or even a paltry $150,000 a year, ought to be a mite more kindly inclined toward his native land.