My husband and I spent this past weekend in our beautiful capital visiting the museums, the government buildings, the gardens -- all that the enthusiastic tourist usually does.

But of all the sights we saw, there is one that will remain indelibly etched in our memory of that searingly hot, humid weekend. It is of a lone carriage horse valiantly straining to pull loads of passengers around the Mall again and again from morning, when we first saw him, until we left at 4 p.m., by which time he was near collapse, with six people in the carriage. The temperature by then was 97 degrees. In response to my protests, the driver merely smiled.

I called the D.C. Animal Control Bureau, which (after lamenting the fact that, of all the policemen posted in that area, not one had done anything about it) promised to send a truck to check on this. Evidently they didn't send the truck, for that same evening the horse, carriage and driver appeared at our hotel looking for more business. The horse was much the worse for wear.

In New York City it took the deaths of four carriage horses on one scathingly hot summer day to prompt the city to prohibit the working of horses when the temperature rises above 90 degrees. Surely a world-class city such as Washington could do the same.

Could not the city enforce standardized regulations, rather than leaving matters to "the judgment of the individual driver" (the current procedure, according to the Washington Humane Society)? Could it not require visible licensing of carriages? Could it not limit the hours a horse must work?

RUTH LURIE PERLMUTTER Maplewood, N.J.