Upcoming in 2012

In the first half of the 19th century, it became apparent that many animals had once lived on the earth and were now extinct. But humans were still outside the realm of prehistory. Several discoveries in the 1830s and 1840s suggested to some that humans were ancient, but such claims were almost universally rejected.

Then, in 1859, the scientific world did a rapid about-face. The discovery of human tools, found alongside extinct animal remains, in a cave at Brixham, England, caused archaeologists to take another look at previous evidence for human antiquity, and decide that the evidence was convincing after all.

By 1870 the discoveries of Neanderthal (1856) and Engis (1833) had been re-evaluated and accepted as genuine, and new finds had been made at Cro-Magnon cave (1868) in southern France. New Neanderthal remains were found in France in the 1880s, and, in 1891, the most primitive human yet found, the so-called Java man, was unearthed in the East Indies. By the end of the century, even popular literature was displaying restoration scenes showing cave men fighting saber-toothed tigers, and human antiquity was a commonly accepted concept.

The exhibition documents the discovery and the acceptance of human antiquity. Visitors to the exhibition will see the first published images of the fossil remains of Neanderthal, Cro-Magnon, Homo erectus, and Australopithecus, as well as stone tools, excavations, and cave art. An added visual touch will be the display of reconstructed skulls, bones, and tools from fossil hominids.

On Time: The Quest for Precision
September 2012 - March 2013

Is time a fundamental dimension of the universe? Can it be measured in any absolute sense? Is time merely a human invention that allows us to artificially compare events in sequential order? We may be uncertain about how to define and explain time but at least one thing is certain. We sure know how to measure it.

For centuries, the instruments used to measure the sun's changing position during the day and during the year were distinctly non-mechanical. The first mechanical clocks in the thirteenth century may have been crude, imprecise, unreliable instruments. Yet by introducing a mechanical means of generating and counting a repeating beat, they marked a revolution in timekeeping. Their use of oscillating motion to divide time into countable beats was the basis for all subsequent improvements in timekeeping.

Pendulum clocks were an invention of the seventeenth century, and they brought the accuracy needed for scientific observations. With spring balances, clocks and watches became wonders of mechanical complexity and, in the case of watches, of miniaturization. Measuring the frequency of vibrating quartz crystals brought another revolution in the twentieth century. Quartz clocks, with accuracy within two thousandths of a second per day, were unmatched in their precision by any mechanical clock or watch. Today atomic clocks have rendered obsolete the definition of a second as a fraction of a solar year. Instead, a second was redefined in 1967 in terms of the vibrations in the cesium-133 atom.

The books and journals in the Linda Hall Library document these revolutions in time keeping. Major advances, interesting alternatives, and innovative applications of available methods of time keeping will tell the story of our ongoing attempts to tell the time, precisely.