-
7. Time's Shadows
- Indiana University Press
- Chapter
- Additional Information
7 Time’s Shadows 61 Around the time of the summer solstice the sunlight can become almost unbearable both in its intensity and in its duration. Yet it was a fitting time to chance upon a remarkable instrument by which, in a former time, sunlight provided the measure of time. I found it on the side of an old house in the nearby village of Bergheim. Set between two second-story windows above a small shop, the astronomical sundial consists of a painted square some two meters wide from which extend three metal rods. On the white background there is superimposed, near the top, an image of the sun; it is represented as a radiant face. Above the sun face there are two inscriptions. The first reads: “Sicut umbra fugit vita” (Life is fleeting just like a shadow), while the other, just below the first, indicates that the sundial was made in 1711. From the face of the sun, arrows radiate out–to the side and downward–to two three-sided bands running along the sides and the bottom of the square; Saint-Hippolyte Alsace June 62 LIGHT TR ACES on the bands are inscribed the hours of sunrise and sunset, the signs of the zodiac, and the months of the year. Along both sides of the arrow that points directly downward, the hours of the day are indicated. At the center of the square, directly below the face of the sun, two of the metal rods extend at an angle from two points on the surface, meeting so as to form with the surface an equilateral triangle. From the point where these two rods meet, a third, longer rod extends upward to the face of the sun. It is from the shadow that the three connected rods cast across the surface of the sundial that the various determinations of time can be read off, most directly the time of year (the month) and the time of day (the hour). It is the shadow that gives the measure of time; and it can hardly have been simply by chance that the inscribed word that is placed at the very top of the sundial directly above the face of the sun is umbra. When I first came across the sundial in midafternoon, a few clouds had gathered, blocking the direct sunlight so that no shadow was to be seen on the sundial. Without seeing the time-measuring shadow, it was difficult to discern just how the instrument performs its function. But once the sun reappeared, the shadow was cast, and the functioning of the sundial was evident. There appeared two long triangles, one inscribed in the other and sharing up to a point its (unmarked) base. The longer triangle extended down well below the sundial onto the bare side of the house, while the other came just about to the bottom of the painted surface. The one side of the longer triangle that it shared to an extent with the other triangle formed the indicative part of the shadow: it crossed the central, downward-pointing arrow at precisely the point designating–correctly–that it was 4:00 pm in the month of June. 63 TIME’S SHADOWS Through its connection with the sunlight, such an instrument measures time concretely, in contrast to the abstract measure provided by mechanical clocks. For the means on which it depends, namely, sunlight and its effect, is none other than that by which time–its hours and seasons–is naturally determined. The time that is determined in this way is that of nature, or rather, of the space encompassed by the natural elements, preeminently by earth and sky. It is the time that holds sway in this natural abode of humans and of the other living things known to us, all of which are subject to the comings and goings of sunlight and all that accompanies the alternation of day and night and the course of the seasons. We can of course abstract from this naturally measured time, measuring it instead by reference to other regularly recurring phenomena such as the swinging of a pendulum or the frequency of a certain radiation; yet such measures typically retain some reference back to the natural measurement. It is indicative of our bond to the natural measure of time that even where the measure is extended completely beyond our natural abode and applied to cosmic phenomena such as stars and galaxies , the measuring units are still derived from the...