Recent District Line Columns have dealt with misspellings and typographical errors.

On Aug. 27, I said,"If there is a computer that corrects typographical errors on its own initiative, I would certainly like to make its acquaintance."

I have now made its acquaintance. I haven't met it personally, but we're pen pals.

Gary E. Clark of Bethesda introduced us by mail. The computer is known as the UNIX operating system, and Gary learned about it from a Bell Laboratories advertisement in the August issue of the magazine Physics Today. He says similar ads have appeared in other scientific magazines.

Bell Labs say UNIX simplifies the use of computers and is designed to handle a variety of applications. It is being used to "manage and maintain the communications network, control experiments, develop software, process text, prepare documents and teach computer science."

For example,"In text processing, the command 'Spell Bell Labs Ad' tells a computer to roofread this ad against a dictionary filed in its memory." Presumably if a word in the text of the ad is misspelled, the computer will correct it.

I find this utterly amazing because the typing mistakes that I make very often result in the appearance on my video display terminal of a word that would be perfect in some other context, but not in the sentence I am trying to construct. The word may be spelled right, but it just isn't the right word.

Example: I want to write, "John went to the theater." But when the brain is in high gear and thoughts are spilling out a little bit faster than fingers can record them, that sentence can sometimes become, "John went to to the theater." Or, "John went the the theater." Or the error can take the form of the one I made near the end of the previous paragraph -- the one in which "spell" should have been "spelled." I didn't make that mistake on purpose, but when I noticed it on a subsequent reading I decided to leave it uncorrected as an illustration.

It is difficult for a writer to proofread his own composition because the writer remembers what words and letters are supposed to be present, so he anticipates. His eye tends to see what should be there rather than what is there.

Even those of us who try to overcome this difficulty by silently but methodically syllabifying each word sometimes fall into the trap of anticipating -- and therefore "seeing" things that are not really present. And many of the errors we miss are good English words, properly spelled, but not the words we intended to write. This is why I find the Bell Labs automatic spelling gizmo utterly amazng. How does Ma Bell know which word I had in mind, or which one makes sense in my sentence?

I suspect that our dear friends the Russkies are just as amazed as I am, and that they try to keep abreast of computer advances of this kind by buying up whatever hardware and software is available to them. If we are stupid enough to sell advanced technology of this kind to them, I hope it programs itself to self-destruct before they can learn anything from it. A machine smart enought to know whether I mean "spell" or "spelled" ought to be smart enough not to give aid to the enemy, even if the humans who own it are not. POSTSCRIPT

In Sunday's financial section, we published an Associated Press story that contained the sentence, "It's like taking your hand out of a vice -- the pressure's off, but you're still hurting."

I find myself wondering whether Unix would understand that "taking your hand out of a vice" doesn't make much sense, even though "vice" is properly spelled if the reference is to sin. Would UNIX know that what really hurts is having your hand squeezed by a vise, rather than a vice?

Similarly, Sherry Reed of Martinsburg, W. Va., was puzzled to learn from a recent TV collumn that local broadcasters were "pouring" over the latest Arbitron ratings. Sherry asks, "What were they pouring -- tears? If the writer meant poring, tell him it has no u."

I don't have to tell him; he knows. Our problem is that the hand is sometimes quicker than the eye. REDUCTIO AD ABSURDUM

Herm Albright says in his column in the Perry Township (Ind.) Weekly:

"Sidney Jarcho writes in The New York Times that he received a phone call from a Con Ed service rep. 'I asked him to call back in a half-hour,' says Jarcho.

"The caller replied,'Certainly -- and have a good half-hour.'"

Herm also reports that Perry Township has been just as hot as Washington this summer. In fact, it was so hot that one of his readers saw a mockingbird pulling a worm out of the ground -- "and he was using a potholder."