Hours: Open seven days a week, 11 a.m. to 2 a.m.; kitchen closes at 11:45 p.m!

Atmosphere: From noon to 9 p.m., hamburger bistro; after that, hard rock cafe.

Price Range: $1.85 for plain hamburger to $114.62 for elephant gizzards, with stops in between at $2.95 for combination sandwiches, $2.15 for such specials of the day as beef stew, lasagna or fried clams and $7.95 for a 12-ounce steak.

Reservations: No.

Credit Cards: Accepts major credit cards.

Special Facilities: Accessible to patrons in wheelchairs, especially at dinner hours.

We've passed Mr. Henry's at Tenley Circle on our way home from late-night movies and taken note of the smoky haze and blaring rock emanating from within. It was, in our book, a place for the young and single.

We've also passed Mr. Henry's at lunch time on spring, summer and fall days and been tables set out on the sidewalks and people of all ages peacefully munching on hamburgers and sandwiches.

One evening, when the chief cook and car pool driver in our house was unable to handle dinner, we decided to zip over to Mr. Henry's and check out the 7 p.m. weekday ambiance. Our children were ecstatic. Hamburger is always a favorite of theirs for dinner. My husband was less enthusiastic. He was too hungry, he said, for a quicky hamburger-french fries dinner.

Fortunately, mr. Henry's menu held out the promise of accomodating all of us. Unfortunately, the evening we were there, the soup of the day, the daily special, spaghetti, salad and bread, $1.95; spare ribs, $2.95, and veal parmesan with fries, salad, a vegetable and bread, $4.25, were crossed out.

The menu, which was printed on our place mats, offered other palatable suggestions - and a few silly jokes. Among the special platters; elephant gizzards, $114.62; among the specialty drinks: Hop, Skip and Go Naked and Glass of Water. Our children thought the menu was hysterical.

They concentrated on the "Sandwiches Hot and Cold" section of the menu. There they found dollar steak, photo chips, $1, and the less droll bacon cheeseburger, hamburger, cheeseburger, roast beef, corned beef, hot pastrami and ham sandwiches for $1.85 to $2.95. My son, 10, debated briefly between a bacon cheeseburger, $2.50, and a 12-ounce New York sirloin, $7.95, and finally opted for the burger.

Our daughter, 12, noticed a hot ham biggie, $2.95, which promised to be an open-faced sandwich with ham, melted Swiss and American cheeses and fries. She wanted it. My husband, appetite raging, debated about fried shrimp, $5.95, or a reuben sandwich, $2.95, but went with the 8-ounce New York strip steak, $5.95. I ordered the steak sandwich, $2.95. Our waiter duly took our orders for medium rare. We all ordered small salads, 75 cents each, and had the usual selection of dressings.

The salads came quickly: iceberg lettuce with dressing in a little cup on the side. Then a rather long wait began. The surroundings were pleasant enough. It was a cool, lovely fall evening and we sat outside at a round table covered with a red-checked oilcloth tablecloth. There were a few other patrons there, but it was hardly crowded.

My steak sandwich, with an adequate-sized piece of charcoal-broiled meat, was rare, as ordered. It arrived first. In fact, it was first by a good 15 minutes. We queried our waiter about the delay of the other meals. "Rookie Chef," he told us.

The rookie chef finally managed to complete the rest of our order. The bacon cheeseburger was fine: Juicy and charcoal broiled with a generous serving of bacon and cheese.It, like the steak sandwich, ham biggie and strip steak, was served with french fries that had been cut from unskinned potatoes. This was not, to our way of thinking, a point to be criticized. It made us feel the potatoes were fresh, and were cooked and cut by real people in a real restaurant. Besides, the skin gave the fries a nice taste.

The hot ham biggie, unfortunately, was rather dried out and the cheese had long since cooled by the time it was served. Our daughter protested that she liked it just fine the way it was, but my husband's steak was much too red to be acceptable, especially since he'd ordered it medium rare. It was taken back to the kitchen, regrilled and returned.Once it achieved medium rare status, the steak was quite good. It had a nice charcoal taste, was tender and altogether acceptable, especially considering the price, $5.95.

We weren't interested in dessert, which our waiter said was limited to cheesecake, and were waiting for our check when a van pulled up and unloaded some rock musicians and their instruments. It struck us that between noon and 9 p.m. Mr. Henry's was an ordinary and pleasant hamburger-sandwich-steak place, a place you could go on famillie for a relatively quick and simple dinner, especially once the rookie chef pulls his orders together. After that, Elephant beer, at $1.70 a bottle, is probably in greater demand than hamburger.

Our tab for hamburger, sandwich and steaks, one beer and the salads came to $19.75.