Our heads are natural magnetic compasses, according to a recent series of experiments in England, that can tell us the rough direction of home even if we have been carted 40 miles away, on roundabout routes, blindfolded.

Dr. R. Robin Baker, reporting in Science magazine this week, said it has been known for years that many animals -- including snails, bees, fish, bats, rats and birds -- can get home when released far away. The mechanism operating in most of the animals is believed to be an ability to read the earth's magnetic field, and to sense from that reading the direction of home.

But no one thought to test humans for the same ability, Baker said, so he did it.

He recruited 137 students at Manchester University in England, and took them on a circuitous trips to different locations varying from 5 to 40 miles from home point at school. The students were blindfolded and were driven, with no talking allowed on the trip, to their destinations.

The routes contained varying degrees of trickiness. Some backtracked, some took long, slightly curving roads, some took detours through the maze of streets in suburban housing tracts.

When the students arrived at their secret destinations, they were taken from the van one at a time and asked, while still blindfolded, to name or write down the compass direction toward home.

To check the results of the experiment further, Baker tied six-inch bar magnets to the heads of some of his subjects. He reasoned that the magnets should cancel or distort the wearers' ability to sense the earth's magnetic field. So he expected this group to be less able to point toward home.

The students' estimates of direction came out this way (some went on more than one outing).

Out of 127 estimates by students not wearing magnets, 85 were correct to within about 45 degrees, or a one-eighth segment of the compass circle. Of those 85, 40 were within about 20 degrees and 26 made it to within about 10 degrees of the right direction.

If the estimates had been a matter of sheer chance, there should have been just as many pointing in exactly the wrong direction as the right direction. Actually, only half a dozen students named exactly the opposite direction from home.

The students with magnets on their heads did significantly worse. In four groups, two with magnets and two without, the students with magnets got the direction wrong by an average of 50 degrees more in one case, and by 25 degrees more in the other.