Often the tools themselves are objects of striking beauty. In some cases, the investigators have been their own craftsmen. Maybe they have formed alliances with instrument makers. But in all instances of toolmaking, there has been a partnership between science and craft, between the desire to know and the means to find out.

This exhibit presents selected instruments and artifacts from the collections of the Caltech Archives. From ancient Egypt, the lands of Islam, and Renaissance Europe come a variety of small but precious objects. Colonial American science is represented by its most famous practitioner, Benjamin Franklin. Two prominent firms from Victorian Britain, the Cambridge Scientific Instrument Company and James White of Glasgow, contribute instruments capable of sophisticated electrical measurements. And from Caltech's own instrument shop in modern Pasadena comes a series of Robert Millikan's original cosmic-ray apparatus.

Read on for a close-up look at each exhibit in the reading room.

Tycho Brahe with his mural quadrant

Tycho Brahe was the greatest observational genius in astronomy before the age of the telescope. Under the patronage of the King of Denmark, he built and operated the observatory of Uraniborg, which was filled with elaborate instruments of his own design. The mural, or Tychonian, quadrant was actually a very large brass quadrant, affixed to a wall. Its radius measured almost two meters and was graduated in tens of seconds. Sightings were taken along the quadrant through the small window in the opposing wall, to which Tycho points. The clock shown at the bottom right, accurate to seconds, allowed the observers to note the precise moment of observation.

This picture is one leaf of a set of unbound book signatures from the collection of Earnest Watson. The signatures once belonged to volume one of the great eleven-volume Atlas maior by the well-known seventeenth-century cartographer Joan (or Jan) Blaeu of Amsterdam. Printed in 1662, Blaeu's elegantly executed and handsomely colored prints were actually copied from Tycho Brahe's Astronomiae instauratae mechanica, first published in 1598.

Earnest Watson (1892-1970)

The collecting of treasures in the history of science was Earnest Watson's passion. Over the years, he purchased for Caltech and for his private collection many choice books, prints, rare artifacts and historic apparatus.

Watson arrived in Pasadena in 1919 to take up a position as assistant professor of physics at Throop College. Having already served as Robert Millikan's trusted graduate assistant at the University of Chicago, he wold play a prominent role at Caltech during the Millikan years as teacher, public lecturer and administrator. The Caltech Watson Lectures are named in his honor.

Early Egyptian statuette of Imhotep & replica

Imhotep (left) is referred to as "the first engineer" since he is reputed to have been the builder of the first pyramid. He lived during Egypt's Third Dynasty. The bronze statuette rests on a wood base which bears the marking: "XVII[th dynasty], Tel el Amarna." This would date the statuette between 1530 and 1320 B.C.

Purchased for the Institute by Earnest Watson, 1957.

The plaster model of the early Egyptian statuette (right) was presented to the Caltech Class of 1939 by Earnest Watson and John R. MacArthur.

MacArthur was Professor of Languages for many years, and Dean of Freshmen from 1923 to 1937.

Earnest Watson surrounded by his treasures

For years Earnest Watson and his private collection occupied Room 114 in East Bridge. Many of Watson's own books and prints were later given to Caltech.

Early Egyptian plumb bob

The plumb bob, made of diorite with a bronze ring, is the Archives' oldest scientific artifact. Unchanged in design since 1500 B.C., this surveying tool is still used to determine a vertical line. Acquired by Earnest Watson from the Nahman Collection, Cairo, in 1958.

Early magnetic compass

In a brass case, with ornamental inscriptions in Arabic. The magnetic compass appears earlier in Europe than in the islamic world, where it is known only after the twelfth century. Before that time Islamic navigation was purely astronomical and did not make use of the magnetic compass.

Purchased for the Institute by Earnest Watson in 1957.

Astrolabe

Made of brass with Arabic inscriptions, this astrolabe is of modern construction, ca 1880-1900, probably from Teheran or Isfahan, Iran. Astrolabes were perfected in the Islamic world and first introduced into medieval Europe in the tenth or eleventh century. This instrument, a planispheric astrolabe, was used to tell time, observe the position of celestial bodies and make astrological predictions.

Purchased for the Institute by Earnest Watson in 1957.

Pocket sundial with compass

Called a horlogium viatorium or traveling timepiece, this German instrument is made of gilt brass. It is signed and dated by a Munich maker: "V[lrich] S[chniep], 1586, VIATORIUM." The instrument is adjustable for elevation and for terrestrial latitudes from 42 to 52 degrees. On the cover is a table of latitudes for various European cities.

Purchased for the Institute by Earnest Watson in 1955.

[Continue to part two of the Reading Room Exhibit]