The Broached Thurnel

The broached thurnel is composed of a square; a cube; a triangle and a pyramid, all geometric shapes and solids, which enable mathematical calculations to be determined with accuracy and precision by the craftsman, which in turn enables the master mason to build a structure on a sure and firm foundation.

In Prichard’s Masonry Dissected (1730) the ‘broached thurnel‘ is said to be one of the three immovable jewels of the lodge, and ‘is for an entered apprentice to learn to work upon’. It is generally admitted that the ‘broached thurnel’ was one of the many symbols which used to figure in the work of the old lodges, but which have now disappeared, like the Trowel, the Beehive and the Ark and Dove.

In the Deptford MS (1814–19) we find a further reference:

Master: When you got admittance, what did you expect to see there?

Mason: The tracery board, perpend ashler and broached thurnel.

Master: How did you expect to find them placed?

Mason: The tracery board upon the mosaic paving, the perpend ashler upon the blazing star and the broached Thurnel upon the tracery board.

Master: What does the broached thurnel represent?

Mason: The divine grace of God penetrating our hard and stony hearts.

(The last answer references Ezekiel 11:19 and 36:26.)

A broached thurnel is still depicted on French tracing boards, although long ago it disappeared from English­derived tracing boards, it having been replaced with the smooth or Perfect Ashlar. French Freemasons have always referred to this stone as ‘la pierre cubique a pointe’, which literally means a pointed square stone. The original French ritual, still in use, explains that it is a model of a spire or turret, whose various outlines provide a means of teaching the apprentice how to develop the forms of the square, the triangle, the cube and the pyramid.

The only modern reference to the broached thurnel, is in the ritual of the Royal Order of Scotland, where it is called the ‘broaching turner’.

A ‘broached spire‘ is a recognised architectural term and is defined as ‘a spire without any parapet at its base, showing the junction of the octagonal spire with the square base.’ The sketch [below] illustrates this type of spire, and it will be seen that the spire may be looked upon as piercing upwards through the top of the lower tower.

When we consider the various material objects which are referred to in the masonic ritual, and displayed in the lodges, we note the obvious fact that they are all of such a nature as to convey some moral lesson or remind us of some moral truth, as well as possessing an interest from the practical or operative point of view. Now, if the ‘broached thurnel’ ever formed part of the furniture of the lodge, what moral teaching could be associated with it? A lesson is connected with the various ashlars, as we are aware. Another beautiful allegory is that of the stone which was rejected because its real properties were not understood, and which yet became at last the cornerstone of the building.

There is one such form; a simple shape, yet one of quite equal importance to those already mentioned, and one which while quite equally illustrating the same moral, agrees more closely than any of them with the words ‘cornerstone of the building.’ The stone in question is the topmost or terminal stone of a pyramid.

The connection of the pyramids with masonic tradition, whether by direct descent or by adoption, is well established. I would suggest that a symbol used in the work of a masonic lodge may have had its origin in the craftsmanship of the pyramid builders.

The pyramids were built with their sides formed in a series of steps and were afterwards encased with another layer of stones of such a shape as to leave a smooth outer surface. This construction is shown in the sketch below. At the apex of the pyramid, for practical reasons, no architect or mason would think of leaving a series of joints, but would provide an apex or terminal stone, as shown in the sketch, and this stone would be of a shape quite distinct from any other stone in the structure. It would be fitted only for its exalted position — the cornerstone indeed — for it is the only salient corner, or angle, of the whole building. From the speculative point of view, then, such a stone would lend itself readily to the illustration of the moral lesson.

In the preparation of this article considerable reference was made to The Broached Thurnel, a paper by Bro Arthur Bowes, from the Transactions of The Lodge of Research No 2429 EC for 1912–13, pages 52–56.

Left: Two ‘pierre cubique a pointe’ on the upper right [beneath the moon], from an EA TB in a c1765 ritual in the National Library of Australia.

Centre: A broached spire

Below: The casing stones of a pyramid, showing the apex or terminal stone – a broached thurnel.