Kater pendulum, seconds-beating length model
Date: 1830-1848
Inventory Number: 1998-1-1248
Classification: Pendulum
Dimensions:143 × 9 × 3 cm (56 5/16 × 3 9/16 × 1 3/16 in.)
box: 10 x 154 x 15.5 cm (3 15/16 x 60 5/8 x 6 1/8 in.)
pendulum bob: 9.3 cm (3 11/16 in.)
Accessories: cork-like wooden object; wooden case
2 wooden "fins" (possibly part of case)
4 mounting screws
1 small brass mounting object
1 brass key-like object
DescriptionLong flat brass bar with a bob on one end, a weight adjustable for position along the pendulum in the middle, and an adjustable pivot on the other end.
At the left end of the pendulum is a pointed tip coming out of the center of a short iron cylindrical weight with two barbs to hold the weight in place. Next to this weight is a plate of brass riveted onto the main bar. Embedded in that are two cylinders, one of them ridged and larger than the other. The larger one is the head of a screw that passes lengthwise through a slot in the bar and adjusts the height of a metal knife-edge pivot. The pivot is on the wide end of the brass slide. On the side of the slide is a screw to fasten the pivot at a particular height. Under the slide is a scale in cm. On the side of the slide is a scale in increments of .05 cm.
Toward the middle of the bar are three brass slides of different sizes. Two of them have screws to fasten them at points along the bar, while the third does not. The brass slide closer to the middle is connected to a second slide with no screw on the front. These two slides are connected in back of the bar by a screw that runs through two holes fastened by clamps. The clamp closer to the circular head of the screw is fixed, while the other can be changed by turning the screw. In this manner, the distance between the two slides is determined. The top part of the pendulum where these slides can be adjusted is ruled in mm.
On the other end of the bar is riveted a circular bob, considerably thicker than the bar itself. Through this circle passes the pendulum bar and two L-shaped braces screwed into opposite sides of the bar. At the shorter arm of each L is a metal knife-edge pivot. This end of the pendulum is similar to the other end, as it has a cylindrical brass weight around a small rod that protrudes from the other side and holds the weight in place with two barbs on either side of it.