One of the problems with brass and steel compensations is that there is a relatively small difference in the expansion of brass and steel, so that you either need to use a lot of brass and steel rod pairs, or you need to use leverage, as Ellicott invented.

(image credit: The Vitale Collection Part II    Christie's London auction catalog    26 November 1996)

In Ellicott's version a flat steel pendlum rod had a brass strip attached at the top, and guided by a series of shoulder screws in slots on the way down. This went through to the center of the bob, where a pair of levers pushed the bob up when the brass rod pushes down.  The system is adjustable, by means of those graduated nuts in the side of the bob: These move the fulcrum of the levers. On the bad side, there is SO much friction in the system as to make it almost unworkable. Ellicot recognized this, and that big pair of springs at the bottom is an attempt to counterpoise the heavy bob, but still... These pendulums survive in remarkable numbers, despite the fact that they didn't much work.  Part of the reason for this must be the evident quality of Ellicot's workmanship: The glazed aperture, the elegant cutouts for the adjusting nuts, it's just a beautiful piece of work, as are Ellicott's movements.

(image credit: The Vitale Collection Part II    Christie's London auction catalog    26 November 1996)

Note the massive plate movement with multiple giant pillars. This view shows the extremely well finished dead-beat escapement, and the typical Ellicot pendulum regulation:  That worm-gear driven nut raised the suspension spring between slotted chocks, raising and lowering the pendulum.  Ellicott needed to do this because his bob-mounted compensation didn't allow for a rating nut on the bob.

This side view also shows the thick dial, which is made even thicker at the hour disk aperture, to allow for an exaggerated tapered edge.  You can see how the pointer is mounted in the edge of the bevel.  It's just amazing workmanship throughout.

Here is a view of the movement of a month-duration Ellicott regulator:

(image credit: European Pendulum Clocks Peter Heuer and Klaus Maurice Schiffer Publishing Co. Westchester, PA 1988)

This is a really clever movement layout.  A massive weight would have been needed for the long duration, so Ellicott has inverted the train so that the escapement and pendulum suspension is below, and within the plates. The barrel is in the upper position, to give additional drop, and protrudes behind the plates.  One of the problems with long duration clocks is that as you increase the driving weight, you increase the friction, and here the maker has provided anti-friction roller bearings for the great wheel arbor, front and back.  Again, just a wonderfully made clock.

Here is the case view of the Ellicott regulator from the Vitale collection:

(image credit: The Vitale Collection Part II    Christie's London auction catalog    26 November 1996)

This is a great example of Ellicott's work. The case has a restrained simplicity, depending for decoration upon the mahogany crotch grain on the door and plinth.  Look at that door. Those aren't book-matched veneer panels: Think about the size of that tree.

Here's an Ellicott dial-in-hood detail from a museum in Italy:

(image credit: Museo Della Specola, Bologna)

Shown with the door open, it makes clear how the dial, which should be a bright matte white slivered finish, is pushed to the front, and the shallow moulding above it allows the maximum light and visibility to the dial.

The astronomical regulator at this time begin to split between scientific instruments and fancy presentation pieces for people who wanted to look like they had scientific interests. Here's an interesting example:

(image credit:The Longcase Clock   Tom Robinson    Antique Collectors Club   Baron Publishing, Woodbridge Suffolk, UK   1981)

At this time Scientists begin to mount expeditions for the observation of scientific phenominon, a famous example of which was the worldwide effort to time the Transit of venus to measure the size of the solar system in 1761. Regulators were also used in surveying expeditions. The cases of these tended to be simple box-like affairs like this example, which doubled as packing cases and work stands for running the clock.

Next time: more 18th century clockmaking in other European countries.

Previously:

Monastic alarms and the beginnings of clockmaking
De Dondi's remarkable astrarium
Early tower clocks
Gothic iron clocks
Rennaisance clocks
Early english lantern clocks
Huygens and the pendulum
Fromanteel's English pendulum clocks
Huygens in Paris
Clement and the recoil escapement
Edward East and the golden age
Thomas Tompion
Daniel Quare
Joseph Knibb
Golden age recap
The balance spring
Paris - Louis Quatorze
Paris - La Regence
Graham - Compensation
18th century in the Netherlands
18th century in the Germany