VR-427 Precision Regulator with mercury-compensating pendulum and jeweled pallets of 1 week duration by Hans Römer
Claterbos lists a Mathias Römer in Vienna in 1882, but no longer there in 1895. This period would be appropriate for this clock, suggesting that Hans was Mathias’ brother.
Precision Regulators are the epitome of mechanical timekeepers. Every thing about them is built to last, and to be extremely reliable - achieving an accuracy of a second per month.
This piece achieves such a phenomenal accuracy in two ways - the virtual elimiation of escapement friction with jeweled pallets, and compensation for temperature changes by the mercury pendulum.
Variation of the length of pendulum rods must be eliminated to achieve precise timekeeping. The problem is, a clock with a steel pendulum rod which runs correctly at 60ºF would run slow by 5 seconds a day at 80ºF. George Graham demonstrated in 1715 a method of compensating for the change in length of a steel rod through the use of mercury. The lengthening of a steel pendulum rod with increased temperature lowers the pendulum's center or gravity or “vibrating point”. However, in a mercury compensating pendulum, the mercury, as it fills a larger part of the glass container due to its expansion, lifts its center of gravity, thereby compensating for the lowering due to the lengthening of the pendulum rod.
This clock is not only amazingly accurate, but also very attractive. The porthole case, with its removable hood and locking doors to both the hood and body, is beautifully finished inside and out: Even the wooden trips holding in the glass are perfectly finished. Note the wall stabilizers with locking nuts to all four corners of the case - allowing one to precisely locate and to minimize any case movement on the wall. And, while the case could use a good cleaning and waxing, it is absolutely gorgeous, as seen in the pictures. It really is difficult to communicate the overall impact of this clock, but I will do my best to describe some of the details that impress me - hopefully this will help you understand my appreciation of this beautiful piece. Note the massive mechanism mount - with arms that support the mechanism being a full 1 inch square where they attach to the backing plate. And the case is not veneered - unless you consider layers of mahogany that are 1/4 inch thick as veneer! Needless to say, the trim pieces are solid mahogany. A minor point, but one that a clockmaker would especially appreciate, the suspension spring has flat springs that hold the upper pin in its slot on the upper hanger - making it so much easier to hang the pendulum. Speaking of the pendulum, there really are few that match the style of a mercury pendulum. Not only do they provide excellent temperature compensation, but they do it in an elegantly functional manner. And, while the jars are a bit dirty, I will be happy to clean them and the mercury before shipping.
Note too the 5-spoke pulley, correct winding crank, engraved and silvered dial with beautifully blued hands, old glass throughout, jeweled pallets, 4 mm (1/6 inch) thick plates, maintaining power, counter-balance mounted to the hour cannon to compensate for the weight of the hour hand, and the small weight shelf on the pendulum rod for the most precise rate adjustments: Everything about this clock bespeaks quality and precision. I especially like the hands, with their striking contrast between the deeply blued hands and the highly polished mounting nut and central hubs. And then there is the pendulum rating nut, with the blued pointer and the marks around the rim for precise rate adjustment.
Read MorePrecision Regulators are the epitome of mechanical timekeepers. Every thing about them is built to last, and to be extremely reliable - achieving an accuracy of a second per month.
This piece achieves such a phenomenal accuracy in two ways - the virtual elimiation of escapement friction with jeweled pallets, and compensation for temperature changes by the mercury pendulum.
Variation of the length of pendulum rods must be eliminated to achieve precise timekeeping. The problem is, a clock with a steel pendulum rod which runs correctly at 60ºF would run slow by 5 seconds a day at 80ºF. George Graham demonstrated in 1715 a method of compensating for the change in length of a steel rod through the use of mercury. The lengthening of a steel pendulum rod with increased temperature lowers the pendulum's center or gravity or “vibrating point”. However, in a mercury compensating pendulum, the mercury, as it fills a larger part of the glass container due to its expansion, lifts its center of gravity, thereby compensating for the lowering due to the lengthening of the pendulum rod.
This clock is not only amazingly accurate, but also very attractive. The porthole case, with its removable hood and locking doors to both the hood and body, is beautifully finished inside and out: Even the wooden trips holding in the glass are perfectly finished. Note the wall stabilizers with locking nuts to all four corners of the case - allowing one to precisely locate and to minimize any case movement on the wall. And, while the case could use a good cleaning and waxing, it is absolutely gorgeous, as seen in the pictures. It really is difficult to communicate the overall impact of this clock, but I will do my best to describe some of the details that impress me - hopefully this will help you understand my appreciation of this beautiful piece. Note the massive mechanism mount - with arms that support the mechanism being a full 1 inch square where they attach to the backing plate. And the case is not veneered - unless you consider layers of mahogany that are 1/4 inch thick as veneer! Needless to say, the trim pieces are solid mahogany. A minor point, but one that a clockmaker would especially appreciate, the suspension spring has flat springs that hold the upper pin in its slot on the upper hanger - making it so much easier to hang the pendulum. Speaking of the pendulum, there really are few that match the style of a mercury pendulum. Not only do they provide excellent temperature compensation, but they do it in an elegantly functional manner. And, while the jars are a bit dirty, I will be happy to clean them and the mercury before shipping.
Note too the 5-spoke pulley, correct winding crank, engraved and silvered dial with beautifully blued hands, old glass throughout, jeweled pallets, 4 mm (1/6 inch) thick plates, maintaining power, counter-balance mounted to the hour cannon to compensate for the weight of the hour hand, and the small weight shelf on the pendulum rod for the most precise rate adjustments: Everything about this clock bespeaks quality and precision. I especially like the hands, with their striking contrast between the deeply blued hands and the highly polished mounting nut and central hubs. And then there is the pendulum rating nut, with the blued pointer and the marks around the rim for precise rate adjustment.
