BIRDS' NESTING SEASON 147 



On the following morning, with a spanking breeze 

 behind us, we sailed across to Mousa. The castle, 

 which stands only a few yards from the shore, on the 

 west side of the island, is probably the oldest building 

 in the British Islands in anything like a complete state, 

 and is of almost startling interest. 



Ruins of squat round towers, known as ' brochs,' built 

 of stone without mortar the connecting-link, according 

 to Sir Walter Scott, between a fox's lair in a cairn and 

 a human habitation of which nothing is known, 

 excepting, perhaps, that when the Vikings made their 

 first descents a thousand years or more ago they found 

 them standing and took possession of them are 

 scattered plentifully on the cliffs of the mainlands and 

 islands of the north of Scotland. 



The Broch of Mousa is the only one in existence 

 which still stands, in all essential particulars, as in all 

 probability it stood when originally occupied. It is a 

 circle of stone wall about 40 feet high shaped like a 

 chess castle with the battlernented top cut off. The 

 outside diameter is about 50 feet at the base and 

 38 or 40 feet at the top. It is bearded on the out- 

 side with a venerable growth of grey lichen, and tapers 

 gradually from the bottom, until, within a few feet 

 of the top, it slightly widens again, so that the actual 

 top almost imperceptibly overhangs. 



It is not easy, without going into too much detail, to 

 give an intelligible description of a building so com- 

 pletely at variance with every modern idea; but the 

 very rough sketches given on the following two pages 



