At long last I got around to photographing my motley crew of three cased Brunel compasses, primarily to compare details with another example of the type recently acquired by David Riches. I suspect all three of mine were made by the Elliott firm, as was almost certainly David’s. However, only the youngest of mine has any kind of identifiable mark – a gold Elliott Bros crest inside the case – and none of the instruments is signed, unlike some later Elliott examples.
All three of mine share the hollow telescopic tube design with locking nuts, although one has lost its thumbscrews completely and another has what look like replacements with slotted heads. All three also have needle points on the divider legs and an angled pencil holder (the earliest engravings show plain points and a straight porte-crayon holder).
The three cases are quite different from each other, which at first glance would seem to suggest different makers. However, they all reflect the changing practices of William Elliott and his sons over the course of their business.
Example 1 – unsigned
What I take to be the earliest set is housed in a rectangular case with small hook fastenings, the outside finished in a thin black leather-effect covering that has worn to a dark green in areas.
This is similar to the cases used for scales, spring bows and pocket compasses by William Elliott in the 1840s and earlier. Internally it is lined with red silk and silk velvet, again in keeping with early Elliott cases up to the 1840s.
As well as space for the compass, there are two slots that I believe would have held a ruling pen and three spring bows to make a complete pocket set of drawing instruments.
Unfortunately, only the spring bow divider remains – distinctly Elliott-like in its details – along with an odd little ink spring bow based on the Swiss type (although the knurled handle has something strangely English about it).
Example 2 – unsigned
The next compass comes in a shaped case covered with Morocco leather, reminiscent of the kind used for pillar compasses and proportional dividers. Elliott Brothers continued to use these fitted cases for certain instruments well into the 1860s, as seen with my example of Ogle’s aphemetric compass.
The case is lined with blue silk and velvet, which became the prevalent colour scheme from the 1850s onwards. If it was indeed made by Elliott, the lack of any signature would suggest a date from the earlier part of the decade, perhaps during the brief Elliott & Sons period.
Example 3 – Elliott Brothers
Finally there is my Elliott Bros example, the Morocco case of which reverts to the familiar rectangular format, although sadly in a very distressed condition (for some reason Brunel compasses seem to be one of the most mistreated of all drawing instruments).
The blue upholstery and gilt crest remained in use for the rest of the 19th century with only subtle changes to the logo which make these sets very difficult to date with any degree of certainty. Both this and the second set include a compass key/screwdriver for adjusting all of the various joints that were so crucial to the proper functioning of the Brunel compass.
Additionally, the case has two empty recesses that appear to have held a pair of tiny spring bows, again with the intention of making a complete but portable drawing set. Whether these were sold as standard or made to order is unclear to me – I only recall seeing Brunel compasses listed as standalone catalogue items (Elliott referred to them as “Tube compasses”), but they often appear in sets.
So much for the boxes, but what about the compasses themselves? Superficially, there is little to tell them apart, all being about the same size and proportion. The differences between them are small and subtle. For example, the red-cased compass has slightly longer joints at the ends of its telescopic legs, similar to David’s example. The steel washers between the legs and rotating points are also thinner, resulting in a narrower gap, and the screw heads less prominent than on my other two. This example is made of a whiter Electrum than the other two, more crisply finished and with noticeably smoother action. On the other hand, the welds down the outside of the tubes are more visible in this compass, possibly due to their increased contrast with the lighter metal.
Dimensionally, the first two are almost exactly the same length at just over 6 1/2 inches. The third, in the signed case, is slightly longer by about one eighth of an inch, partly attributable to the lengthened shoulders below the head joint. In all three compasses, the locking nut centres are exactly the same distance from the end of the tube, at just under 7/8″. Likewise, at full extension they can all draw a circle of just over a foot in radius.
Other elements of the three compasses differ by similarly small amounts, as can be seen from the selection of dimensions that I took with digital calipers measuring to 1/100th of an inch (all dimensions below in inches, listed in assumed chronological order as above):
0.25 / 0.26 / 0.24 – single leg tube outer diameter
0.48 / 0.48 / 0.47 – compass head outer diameter
0.32 / 0.31 / 0.32 – compass head front washer diameter
0.71 / 0.73 / 0.75 – compass head plus shoulders height
1.04 / 1.09 / 1.04 – total compass width (closed) at moving leg pivots
0.87 / 0.84 / 0.84 – total length knee joint blocks
0.25 / 0.25 / 0.24 – turning leg depth at pivot
0.23 / 0.24 / 0.25 – outer face of turning leg step detail
0.58 / 0.61 / 0.61 – pencil holder length
0.19 / 0.20 / 0.19 – pencil holder outside diameter
0.75 / 0.64 / 0.80 – length of top steel pen blade
0.28 / 0.33 / 0.27 – pencil tightening nut diameter
0.23 / 0.24 / 0.22 – needle point nut diameter
0.30 / 0.32 / 0.28 – pen nut diameter
Clearly little changed in the fabrication of these compasses over the decades, and even the illustration in Stanley’s 1866 book (see 1868 edition at archive.org) looks most like the earliest Elliott examples. Unlike some other instruments, Stanley himself did little to change the design beyond restyling the shoulder connection and adding his patented nut and bolt points to the turning legs. The main difference is that Stanley preferred a solid bar construction for the inner telescoping tube, dispensing with the troublesome locking nuts entirely (it is worth noting that this was not an innovation of Stanley’s, as the solid bar had previously appeared on instruments made by William Elliott, albeit infrequently). Tubular compasses were still being sold by Stanley after he had moved to his 286 High Holborn address, but presumably in very small numbers. By 1931 they had disappeared from his catalogue.
Before leaving the subject, I should clarify that despite using the term “Brunel compass” throughout, the attribution to Marc Isambard Brunel is no clearer than it was when last discussed in the Drawing Instruments group. Hopefully this renewed attention will lead to some more evidence being unearthed about the earlier years of the instrument’s development.
