In the first half of the 19th century a separate style of pendulum clocks was developed. These wall and floor clocks are usually provided with an enlarged hood, and have a case glazed on three sides, with a long central part and wider lower part in which the pendulum swings. They are colloquially referred to as Laterndlclocks. The Laterndlclock is a regulator, which is attached to a wall, and should therefore be free from any vibration so as to achieve accuracy. The formal development of the Laterndlclock goes back to the English longcase clocks of the 18th century, from which the Laterndlclock has its triangular pediment. The lower part of the clock case is fitted with screws made of brass, which serve to stabilize it. The hood of the early clock cases often have a stepped flat top, the lower part is not glazed at the sides. The bottom door, with the pendulum visible, can be pushed up or sideways. The triangular pediment appears later in about 1820, throughout the whole of the former Austro-Hungarian Danube Monarchy. The proportions of the fine Viennese wall and floor clocks from the Vormärz period are considered well balanced, the veneer wood and details are of the highest quality.
The Laterndlclocks of the early days were made by clockmakers Philipp Fertbauer, Caspar Brändl, Matthias Wibral and Anton Glückstein in Vienna, Franz Seiffner and Joseph Lechner in Pest, Joseph Rauschmann in Ofen and Joseph Lehrner in Kaschau. From 1800 onwards the woods used were mainly mahogany with ebonized stringing or edges, later walnut, cherry, ebonized pear, or burr veneer. The clock cases were manufactured by manufacturers who served as suppliers to clockmakers. Other suppliers to clockmakers include the following professions with their historical job titles: Ziffernblattschmelzer, Glockengießer, Tonfedernfabrikanten, Uhrwerkspolierer, Triebfertiger, Graveure, Vergolder usw. For most Laterndlclocks the dial sits freely behind the glass door of the hood. Clocks by Fertbauer, Brändl and Seiffner in Pest on the other hand, have a wooden front to the hood, into which the dial is embedded and covered by a convex clock glass with a gold-plated bezel. Occasionally, the front is decorated with embellishments or ebonized columns. In early days dials were sometimes convex, later flat. There were enamelled or silvered dials, some of frosted glass or even fire-gilt, engine turned and engraved. Joseph Lechner in Kaschau, for example, made a skeletonized year duration clock with a transparent glass dial including his enameled signature. The bezels were made in different widths and were engine turned and fire gilded on good clocks.
The regulators a clock whose time standard is a mechanical pendulum (old term also: ‘Perpendikel’). The basic principle of the regulator is based on a swinging or rotating pendulum, which triggers an action inside the clock movement at a certain point in its path of each passage, by which then the time display is switched by a predetermined amount (e.g. one second). In addition, the pendulum of the clock movement (or another impetus) receives an impulse to continue swinging. The equal measure of the pendulum’s movement is therefore decisive for the achievable accuracy of the clock, which is why greatest attention was given to the construction of the pendulum as well as the non-interference with the clock movement’s impetus. Usual steps are therefore a construction of the pendulum, which makes it vibrate steadily despite all environmental influences such as temperature, air density and humidity, an encapsulation of the pendulum for the same purpose, the steadiest possible induction of movement and the most constant transmission of impulse from clock onto the pendulum. In the first period of the clocks, the hammers strike on bells, later blued wire gongs were used. To protect the clock movement, the Viennese clockmakers Philipp Happacher, Philipp Fertbauer, Ignaz Mahrenzeller, Caspar Brändel, Anton Glückstein and Joseph Binder and Franz Lobmeyer in Tyrnau, Joseph Lehrner in Kaschau, Josef Rauschman in Ofen, Franz Seiffner in Pest, Karl Zelisko and Josef Kossek in Prague, encapsulated the clock movements with cut glass slides.
In the case of the pendulums, the aim was to keep thermal expansion as low as possible as to ensure accurate running (see Lehrner in Kaschau for compensation pendulums made of brass and steel with options of fine adjustment and temperature scale). For the majority of the pendulum dried and lacquered fir wood was used. As for hanging, there is spring or knife edge suspension. ‘laterndclocks’ were built in different sizes, depending on the length of the pendulum. The amplitude of one second still provides for excellent accuracy (second pendulum) of a precisely built clock movement. The precondition is an average length of the clock case of 145 cm. Depending on the maker, clock movement were produced in great variety, with the majority being 8 day duration or month duration with or without striking. The durations varies between 1, 4, 6 weeks, 2, 3, 6 or 9 months up until clocks with a year duration. At the trade fair in Vienna in 1845, the clockmaker Alois Schenk exhibited ‘two observatory clocks with compensation pendulum, one of them working for 3 years and two months". Additional indications (subsidary-dials) for day of the week, date, month, signs of the zodiac, leap year indication, middle and true time, moon phase and moon age, equation or world time dial are some of the special features of this masterpiece.