Abstract: An apparatus and method for recording the compression pressure of internal combustion engines, wherein a pair of recording elements, such as a stylus and a recording sheet, are movable relative to each other by a pressure sensitive element, and the compression pressure acts upon one of the recording elements to first move the recording element from a position of rest, after which the two recording elements are brought into contact with each other, and the pressure is then relieved from the one recording element, resulting in a line being drawn while the recording element returns to its position of rest.

Abstract: An indicator dial having at least one scale thereon and having at least one illuminable indication area for providing a visual signal of a physical function, wherein the dial comprises a thin transparent plate having an opaque dye coat on one face thereof with at least one area free of the opaque dye coat and having a translucent dye coat of contrasting color in the area, and the scale being on the side of the plate facing a viewer, whereby the scale is visible at all times, but the indication areas are visible to the viewer only when illuminated from behind the dial. The dial is made by applying the dye coats and scale markings in sequential operations by use of a screen printing process.