On Monday, I wrote about a deposited check on a New York bank that hadn't "cleared" after 10 days, and a payroll check on a local bank that hadn't cleared after seven days.

My bank's computer still had a "hold" on both checks and didn't permit me to draw cash against them. A bank officer had to intercede before I could cash a small check.

Reader reaction has been pouring in. Of the many reports that have already reached me, the most remarkable may be one from Paul Clemens of Avondale.

Before he went abroad, Paul bought some Thos. Cook & Sons. travelers checks through the American Automobile Association. Throughout Europe, strangers accepted his travelers checks without question.

When Paul returned home, he took his unused travelers checks to the Maryland Federal Savings & Loan, where he has long maintained an account and is well known, and deposited them. The teller cautioned him, "You will not be able to draw against these for 14 days. It takes that long for them to clear."

The inner workings of electronic banking are now emerging into a clearer picture. Apparently each bank enters its daily transactions into a computer that can produce a comprehensive printout in seconds. The printouts are then forwarded to other banks by horse and wagon - while the banks earn interest on millions, or perhaps billions, in customers' funds.

ANY QUESTIONS?

The Mutual World News is described in its masthead as "the community newspaper for Rossmoor, Leisure World of Maryland." The paper carried a classified ad recently that said:

FOR SALE - The Philadelphia Mint. Experienced staff. Mint condition. This opportunity will not knock again."

William H. Sullivan tells me he called the telephone number listed in the ad and asked the man who answered whether the Philadelphia Mint was really his to sell. The man said it certainly was. "I got it from a man who sold it to me in a hotel bar in Baltimore, and I have a valid receipt for it."

WHAT ELSE IS NEW, CLIVE?

Clive W. Hemphill of Arlington owns a motorcycle as well as an auto, and tries to operate bth vehicles safely and obey all the rules of the road.

He says he finds one type of traffic violation especially dangerous and vexing. "Many drivers don't seem to know what turn signals are for," he says. He estimates that fewer than half of all drivers use their turn signals properly.

Sometimes drivers don't signal at all. Sometimes they wait at a red light until it turns green before they activate a left-turn signal. And a few days ago, Clive encountered a car that signaled for a left turn and then suddenly turned right - "the third time in two weeks I have seen this happen while I was using my motorcycle." Suppose Clive had attempted to pass on the right after he noticed the left-turn signal?

He'd have been creamed, of course. Motorists are forever running into two-wheelers. Last year alone, 446,878 bicycle riders were injured by motorists who "didn't see" them. In fact, bicycles cause more people to require hospital treatment than any other product regulated by the Consumer Product Safety Commission.

Motorcycle deaths and injuries have also continued to mount, especially since many states began repealing laws that required the wearing of safety helmets.

But why am I writing all this? There's no news in it. Failure of drivers to use their turn indicators has been deplored by thousands of safety experts, and for good measure by a few safety-minded columnists. Motorists by the hundreds of thousands continue not to see (or be aware of the presence of) two-wheeled vehicles that have just as much right to use our streets and high ways as automobiles.

I just don't know what else can be said on the subject - except this: We automobile drivers ought to be ashamed of ourselves.

There's no way to cut the toll except to suspend or revoke enough driving permits to get the message across.

'TWAS EVER THUS

Paul Sweeney says, "Due to the many break-ins in our area, police recommend that people photograph their possessions so that they will have a record.Our neighbor took pictures of almost everything in his house with his expensive new camera. Guess what was missing after the robbery?"

IS HE SARCASTIC OR SERIOUS?

W.M.O'C. writes, "President Carter says conservation is our most important weapon against OPEC. Perhaps we ought to enlarge high school parking lots so that the kids won't have to ride around so much looking for a parking place."