The Barnhouse Stone
By Sigurd Towrie
A solitary lichen-crowned megalith stands in a field about half a mile to the south-east of the Stones of Stenness.
On first glance the Barnhouse Stone might appear unconnected to the numerous monuments around about, but appearances can be deceptive.
Standing 3.2 metres high (10.5ft), the wedge-shaped monolith is aligned to entrance of Maeshowe, around 750 metres to the north-east, and therefore also the setting midwinter sun.
Local schoolmaster Magnus Spence first documented the connection between the chambered cairn, the stone and the sun in 1893.
From Maeshowe’s central chamber, Spence noted that:
By 1902, Spence’s focus seems to have shifted to the midsummer solstice sunrise. In Maeshow (sic) and the Standing Stones, Stenness: Their Age and Purpose, the winter solstice plays second fiddle to his summer observations.
Introducing the Barnhouse Stone with a rejigged version of his 1893 text, he explained that:
To Spence it was the midsummer sunrise that was important. In a letter to The Scotsman newspaper in 1910, he referred to Maeshowe and the Barnhouse Stone as “an observatory for a midsummer observation”. 
Countering the question why the chamber’s entrance did not open towards the rising sun, he suggested that, on midsummer morning “a mirror placed on the side of the Barnhouse Stone would reflect a beam of sunlight into the inner recesses of Maeshow (sic).” 
Unfortunately for this theory, mirrors – in any form – did not exist in the Neolithic.
As well as the solstice alignments, Spence suggested that the Barnhouse Stone, the Watchstone and the centre of the Ring of Brodgar formed “an alignment pointing to the sunset about the Beltane feast and to the rising sun at the winter solstice.” 
Anyone familiar with the landscape around the Barnhouse Stone will immediately raise a questioning eyebrow at this claim. And indeed, in 1906, the astronomer and physicist Sir Norman Lockyer disagreed.
To Lockyer, the significant times represented by the Brodgar-Watchstone-Barnhouse line were sunset at Beltane and sunrise at Hallowmas. 
Spence himself must have agreed, because he declared, in 1910, that the line “points to the setting sun at the Beltane sun-feast (in the first week of May) and at the other extremity to that of Hallow E’en feast.” 
But these suggested alignments aside, we know very little about the Barnhouse Stone.
While it is presumed, due to the solstice alignment, to have been erected about the same time as Maeshowe, evidence suggests the passage grave sits on top of an earlier building.
In addition, excavation in 1991 also revealed a large standing stone socket hole on the platform to the rear of Maeshowe – the orientation of which led to the suggestion it was part of a stone circle. 
It is not impossible that the position of the Barnhouse Stone related to these earlier monuments.
Although geophysical surveys of the area around the standing stone revealed anomalies nearby, these are of uncertain date and character. 
-  One chain equals 22 yards (20.12 metres).
-  Spence, M. (1893) Standing Stones and Maeshowe of Stenness. The Scottish Review.
-  Spence, M. (1905) Maeshow and the Standing Stones, Stenness: Their Age and Purpose.
-  Spence, M. (1910) Letter to The Scotsman newspaper. June 21, 1910.
-  Lockyer, N. (1906) Stonehenge and other British stone monuments astronomically considered. Macmillan and Company.
-  Challands, A., Muir, T. and Richards, C. (2005) The Great Passage Grave of Maeshowe. In Richards, C. (ed) Dwelling among the monuments: the Neolithic village of Barnhouse, Maeshowe passage grave and surrounding monuments at Stenness. Cambridge: McDonald Institute for Archaeological Research, pp. 229–248.
-  Brend, A., Card, N., Downes, J., Edmonds, M. and Moore, J. (2020) Landscapes Revealed: Geophysical Survey in the Heart of Neolithic Orkney World Heritage Area 2002-2011. Oxbow Books, Oxford.