On further consideration of this remarkable group of excessively peculiar features, it becomes evident that they all point more or less obviously to the presence of a double intention in the minds of the constructors of the Brochs. The design of the whole structure and the arrangements of all its separate parts exhibit a careful and laborious adaptation of means and material to the two main objects of shelter and defence. The clever constructive idea of turning the house outside in as it were, placing its rooms within its walls, and turning all their windows towards the interior of the edifice, implies boldness of conception and fertility of resource. The height of the wall, which effectually secured the inmates against projectiles, also removed its essentially weak upper part beyond reach of assault, while the pressure of its mass knit the masonry of the lower part firmly together, and its thickness made it difficult to force an entrance by digging through it—if such a wall could be approached for this purpose when the whole of its upper materials were deadly missiles ready to the hands of the defenders. The door, securely fastened by its great bar, is too strong to be carried by a rush. Placed four feet or more within the passage, it can only be reached by one man at a time, and the narrowness of the passage prevents the use of long levers. In all probability the door itself is a slab of stone, and impervious to fire. But even if it is forced, and entrance gained to the interior court, the enemy finds himself as it were in the bottom of a well 30 to 40 feet in diameter with walls 50 feet high, pierced on all sides by vertical ranges of windows, or loopholes, commanding every foot of the space below, and rising to the number of twenty or more, immediately over the door which gives access to the galleries. In short, the concentration of effort towards the two main objects of space for shelter and complete security was never more strikingly exhibited, and no more admirable adaptation of materials so simple and common as undressed and uncemented stone for this double purpose has ever been discovered or suggested. Perhaps there is no characteristic of the typical structure more remarkable than the extreme constancy of its essential features. The uniformity of plan and construction is so unvarying among all the known examples that there exists no means of tracing the development of the form through a series of primitive or immature stages. In this respect there is a striking analogy between the Brochs and the Round Towers of Ireland. The Irish Towers also appear fully developed, and exhibit a general uniformity of plan and construction which is quite as remarkable in its manifestations among them as it is among the Brochs.[[76]] Their origin is assignable to peculiar circumstances in the history of the ecclesiastical communities, and chiefly to their constant liability to sudden danger of plunder and murder by roving bands of marauding Norsemen. This specialty of purpose accounts for, and harmonises with, their specialty of form; and their remarkable uniformity of plan is the natural result of the special fitness of the typical form for its special intention—the provision of a secure refuge from dangers which, though of frequent occurrence, were of transient duration.

In Scotland the area which is chiefly occupied by the Brochs was peculiarly exposed to similar occurrences. Over the whole of the northern and western districts there ebbed and flowed continuously for centuries a species of irregular intermittent warfare, consisting chiefly of plundering forays by bands of foreign marauders. And as the special association of the Round Towers of Ireland with the ecclesiastical sites of the country supplies the clue to their special purpose, the Brochs of Scotland have also their special association from which their special purpose may also be fairly deduced. Although they are often placed in situations of natural strength, yet, as a rule, they mark the area of the best land in the districts in which they are situated. This is specially true of their local distribution in Caithness, while in Sutherland we see them thickly planted in the fertile straths, and following the courses of the rivers to distances of twenty-five or thirty miles inland. They are therefore the defensive strongholds of a population located upon the arable lands, and not in the mountain fastnesses of the country; and their peculiar nature as exceptionally secure places of refuge for non-combatants and cattle, and for storage of produce, explains the fitness of their association with the arable soil of the area in which they are most abundantly present. Against such oft-recurring but transient dangers to the cultivators and to the produce of their soil there could be no more effective system of defence provided than a multitude of safes, which should be burglar-proof, and big enough to contain the families, goods, and cattle of their proprietors.[[77]]

If it be thus suggested by the relations of the Brochs to the arable lands of the districts in which they are situated, that they belonged to the possessors and cultivators of the soil, the affinities of the typical structure itself go far to show that in its character and origin it is distinctively Celtic. None of its essential features have been observed in any construction outside of the Celtic area. And within that area no building with a stair and an arrangement of galleries similar to that of a Broch has been met with out of Scotland. But the circular wall, with chambers in its thickness, which may be regarded as the germ from which the Broch structure has grown, is a characteristic feature of Celtic construction. We have met with it in the walls of the cashels surrounding the ecclesiastical settlements of Christian times. It is common in Irish Cloghauns and Scottish beehive houses, and is so persistently Celtic that it appears also in Wales and Cornwall. The ground plan of the most perfect of a group of beehive huts at Bodinar, in Cornwall (Fig. [184]), exhibits an arrangement of oval chambers in the thickness of its wall precisely similar to the arrangement which prevails in the Brochs. The long narrow gallery (the essential feature of the earth-houses of Scotland, Ireland, and Cornwall) is also a form of construction which is specially characteristic of the Celtic area. The typical Broch structure thus presents a combination of features and forms of construction[[78]] which are found existing separately in other constructions of Celtic character and origin, although the typical combination which distinguishes the Broch structure from all others is confined to Scotland alone.

Fig. 184.—Ground plan of Structure at Bodinar, Cornwall.

In the previous course of Lectures it was shown that as a nation we are the possessors of the remains of a school of art exemplified in a series of monumental types which are so truly unique that no other nation possesses a single example. It has now been demonstrated that we are also the possessors of the remains of a school of architecture which is as truly unique and even more pronounced in its features of absolute individuality. I do not claim for it any higher merit than that it has designed a typical form of structure possessed of almost perfect fitness for the purposes for which it was intended. It has no special beauty of form, nor is there evident in any of its parts the least attempt at ornamentation or decorative construction. But, judged by its proper standard—the measure of its fitness for its special purpose—its peculiar characteristics fulfil the most exacting requirements of architectural criticism. The fact that this peculiar type of structure exists only in one area must necessarily have some significance in relation to the history of architecture; but the fact that their remains may still be counted by hundreds must also have great significance in relation to the unwritten history of Scotland, for it is obvious that the presence within its area of this vast series of massive structures, so closely alike in their general features, and so admirably contrived in their special arrangements, implies a wide-spread concentration of thought and energy towards a common object which is found only in communities that have attained to a comparatively high condition of general culture and social organisation.

LECTURE V.
(31st October 1881.)
THE BROCHS AND THEIR CONTENTS.

In 1852 the late Mr. A. H. Rhind of Sibster, the founder of the Rhind Lectureship, made a systematic investigation of an ancient structure at Kettleburn, near Wick, in Caithness. It was a work of great magnitude, employing a number of men for upwards of three months.[[79]] It is easy for us, with more extended knowledge of this class of buildings, to recognise the features of the structure as those of a Broch, although it was not so considered by Mr. Rhind.

The external appearance of the ruin was that of a mound somewhat more than 120 feet in diameter, and 10 feet high. It stood in a cultivated field; the plough had regularly passed over it for a quarter of a century, and a cottage had been built out of one of its sides. Though thus diminished and dilapidated, there remained enough of its structure underneath the surface to show clearly what were its general features.