"If the person so standing turns to his left hand, he will find a groove in one of the 6-foot pillars from top to bottom, which (in the lapse of so many ages, and swelled by the alternate heat and moisture of two thousand years, has lost its shape) might have contained in it a scale of degrees for measuring; and the stone called the altar[3] would have answered to draw those diagrams on, and this scale of degrees was well placed for use in such a case, for one turning himself to the left, and his right hand holding a compass, could apply it most conveniently. With all this apparatus the motions of the heavenly bodies might have been accurately marked and eclipses calculated, a knowledge of which, Caesar says, they possessed in his time.

"Wood and Dr. Stukeley both make the inner oval to consist of nineteen stones, answering to the ancient Metonic Cycle of nineteen years, at the end of which the sun and the moon are in the same relative situation as at the beginning, when indeed the same almanack will do again.

"In my younger days I have visited Stonehenge by starlight, and found, on applying my sight from the top of the 6-foot pillars of the inner oval and looking at the high trilithons, I could mark the places of the planets and the stars in the heavens, so as to measure distances by the corners and angles of them....

"It is very remarkable that no barrow or tumulus exists on the east side, where the sun (the great object of ancient worship) first appears."

[3] "Dr. Smith says that he has tried a bit of this stone, and found that it would not stand fire. It is, therefore, very improbable that it should have been used for burnt sacrifices."

The theory put forward in this article has in late years been upheld by no less an authority than Sir Norman Lockyer, who thinks that the practice of visiting Stonehenge on the longest day of the year—a pilgrimage that goes back before the beginnings of recorded history, essayed by a country people not addicted to wasting a fine summer morning without some very strong tradition to prompt them—goes far to bear out the theory that Stonehenge was a solar temple. If this is so, the mysterious people who erected it were civilized enough to have a good working knowledge of the movement of the heavenly bodies, and probably combined that knowledge with a not unreasonable worship and ritual. Sir Norman Lockyer's calculations give the date of the erection as about 1680 B.C.

Lord Avebury considers that it is part of a great scheme for honouring the famous dead, and many modern writers have adopted the same view. That the Plain near by is a great cemetery is beyond doubt, but then so are more or less all the chalk hills of Britain.

There is more than one explanation of the probable method of the construction of the trilithons. A writer in the Wiltshire Archaeological Magazine (W. Long) puts forward the theory that an artificial mound was made in which holes were dug to receive the upright pillars. When these were in position the recumbent block could easily be placed across the two and, all the trilithons being complete, the earth could be dug away, leaving the stones standing. Professor Gowland, however, does not favour this view in the light of his recent discoveries and is inclined to credit the builders with a greater knowledge of simple engineering.