Virgule Escapement and Calendar Pocket Watch circa 1790
In a suburbs pawnshop, among many boring old watches, my attention was drawn to a large dial with true antique-style numerals. The watch stood out because of its large size (over 60 mm), the dial in the old ‘regulator clock’ style, and there was a hole for the winding key, like you find in large wall clocks. This French watch was also fitted with a wholly unsuitable British body, without bezel or glass, and homemade hands that were threatening to fall off at any moment.
It is not hard to see that the watch was ‘marriaged’ from parts, with the case soldered and reshaped. Fortunately, the previous owner treated the mechanism with care – it even ticked steadily. Inside, as one usually finds in this kind of situation, I found dirt, which was causing the calendar to stick when switching.
The main thing that caught my eye was the mechanism itself. A French engraved balance bridge with two legs, and no fusée. Between the plates an unusual escape wheel with vertical teeth is visible, characteristic only of a virgule escapement. The decision to buy it was obvious, and after a short bout of haggling, the watch was in my hands.
Restoring the Watch
By the evening on the same day of its purchase, I had already completely restored the mechanism. After a complete cleaning, washing, greasing, some parts polishing, some adjustments, and blue tempering of some screws, the watch finally began to shine!
A couple of days later, we found a case in the correct French style that matched the movement. Luckily, the diameter for the bezel, the depth, and diameter for the mainplate, the cutouts for the eyelet and the latch all fit perfectly, with only minor adjustments needed with the file! We only needed to modify the case and didn’t touch the mechanism at all.
Another 3 weeks were spent adjusting the movement, and a large custom-made dome-shaped glass (a special jig had to be made for it). Then all we needed was a pair of gold hands – and the watch is complete.
How the watch looks now after its restoration. The dial resembles that of a large grandfather clock.
A little about the Virgule escapement
The virgule escapement is mentioned in horological literature, watchmaking reference books, and antique watch catalogues. It is extremely rare to come across such a watch at pawnshop, except when they are occasionally sold for a costly price from highly specialised watch dealers and auctions.
This escapement is an early model, developed in 1753 by the famous watchmaker-inventor Jean-Antoine Lepine. The device combined elements of a cylinder escapement and duplex and was quite difficult to manufacture. The running escapement wheel had vertical teeth fixed at 90 degrees to the plane of the wheel. The balance wheel is made with a single comma-shaped tooth attached to it.
The balance arbour is very complex to machine and unusual in shape.
The balance and hairspring are like those in a spindle watch – flat rimmed, with only 3 coils in the hairspring.
In French, the movement is called ‘echappement virgule’, which means ‘comma’, because of the characteristic shape of the tooth on the balance axis. This is why another name for this mechanism is a ‘comma-shaped escapement’.
The accuracy and reliability of the virgule escapement was at around the same level as the cylinder. At the time of its popularity it was difficult to manufacture some of the parts, and thus it was produced for only a short period from about 1775 – 1810, and even during this time it was not widely distributed. Very few watches with this type of mechanism have survived to this day.
Centre Seconds Display
One of the features of this movement is the centre seconds display. This is what the first steps towards developing the chronograph and stopwatch looked like. Clock-counters (compteour), even without the function of a stopping seconds hand, were designed with a conveniently large second scale for measuring short periods of time. At first, the function was only used at pulse measuring and horse races, but later it became essential for the military, engineering, and physico-chemical tasks.
Porcelain (Enamel) Dial
Note that the dial markers are marked after ¼ of a second. You will not find this division in newer watches, where there are usually 1/5 or 1/10 second markings.
The dial itself is totally handmade! It is a porcelain disc with marks, lines, and numbers all applied by hand. Pay attention to the unevenness in the hand-drawn dots between the second divisions, the different lengths of marks, and the different style of the number ‘5’. If the dial is magnified, and you look very closely, the difference is obvious. But without a microscope it is impossible to see it.
Here, too, the slightly uneven lengths in the lines of the Roman numerals are visible, slightly jumping the outline. All the same, this was done very accurately, and these flaws are visible only under a microscope at a high magnification.
The dots underneath the numbers are larger than the rest, which gives the impression of ‘highlighting’ the numbers. The difficulty of hand-drawing enamel watch dials, in comparison to enamel miniatures, lies in the need to perfectly and accurately represent the size, the positioning of the numbers, and the shape and thickness of the lines.
When you hold the watch in your hands, all of the minor flaws become completely invisible. The dial is also very complex, with four rows of numbers, and many marks between the second divisions. Even when using a reducing pantograph, such delicate and painstaking work requires a lot of time and skill.
The Calendar complication
The calendar hand is an interesting and not much common function for the 18th century. During that period, repeaters were much more common than calendars.
This is a high-class feature: the wheels are nicely finished, and a polished click with a spring is supplied. The module is easy to disassemble and maintain, and it is good solid work that is pleasant to look at.
The calendar is perfectly preserved, no bent or repaired teeth. Everything works well – the date switches correctly and smoothly when moving the hands both forwards and backwards.
The Case
The case is in a French style, with an opening front bezel and solid back. Such cases were made for watches with a winding hole on the dial. There is a latch with a button on the side for opening the cover.
The silver case has a very subtle notch pattern on the sidewall. Very unusual hallmarks are stamped inside.
Here we have a small mystery… Such hallmarks as these are not found in catalogues, and the silver experts that I spoke to couldn’t recognise the country to which they might belong to. France, Germany, Scandinavia, and England, all use different badges to these. Only one thing here is clear: ‘H.R.T.’ is the initials of the case manufacturer. Of course, there is no sample number – those began to be used much later on.
Similar timepieces
I managed to find several similar watches in catalogues. Note that the mechanisms are identical – even the winding hole is in the same place.
The watch is housed in a non-original silver case from a later period, with a virgule-type escapement, without a calendar – it sold for $2525. Perhaps the manufacturer of the movement is the same as in my watch – even the engraving on the balance bridge is the same.
Watch with a virgule escapement in an original 18K gold case with pearl inlays. The centre seconds display, instead of a calendar, is an indicator of the phase of the moon. Both watches were sold at Antiquorum in 1997 for $13,600.
Concluding Notes
The combination of a virgule escapement, a centre seconds display, and a calendar created by Swiss craftsmen of the 18th century, is a great rarity. Taking into account the good preservation, performance, and aesthetically appealing appearance of the watch, it occupies a very worthy place in my collection.
Summary details
Virgule Escapement Watch with Centre Seconds Display (Switzerland, 1790’s)
- French-style movement layout, no jewels, with steel ‘coquerette’ piece on an engraved balance bridge.
- Flat brass balance, flat steel hairspring with 3 coils. Silver regulator dial on back plate.
- Virgule escapement: steel balance axle, brass escape wheel with vertical teeth.
- The calendar device is mounted under the dial, driven by a day wheel with a calendar wheel switching tooth.
- Convex ‘regulator’ style porcelain dial. High convex mineral glass.
- The hour and minute hands are positioned at the bottom, the large second hand is centrally positioned, the calendar hand is positioned at the top.
- Silver 18th century case with stamps on the inside. A subtle pattern is cut along the sidewall and bezel.
- The winding of the spring and the hands is carried out by keys on the side of the dial.
