The chronograph was used in conjuction with a transit telescope to make a correction to a clock. The drum was covered with a sheet of paper, and a pen-holding mechanism, now lost, moved along the length of the drum as the drum rotated. The pen made a continuous line on the paper. The pen mechanism was connected to a clock which put out an electrical pulse every second, and those pulses made jogs in the line. An observer at a transit telescope watched for the passage of a star through the meridian, and when the star crossed the cross-hairs of the telescope, the observer closed a switch which produced a different sort of jog in the line. It was then possible to determine within a small fraction of a second what the clock read when the star crossed the meridian. The drum was turned by a spring motor, and the governor to control the speed is in the upper right of the picture. This was part of the equipment in the Grinnell College observatory in the late 1800s.

This chronometer is five inches in diameter. It is mounted in a box with a glass lid (below the wooden lid) and is in gimbals for use on a ship. The lettering on the face reads Ulysse Nardin Locle Suisse A tag with the chronometer says that it was checked by the US Naval Observatory on September 28, 1945.

A solar microscope was placed in a hole in a window shutter with the mirror outside and the barrel extending into a room. Sunlight was reflected by the mirror through condensing lenses, a slide carrying an object to be observed, and projection lenses. The image was projected on a screen in the room. This microscope has no maker's name on it, and its date is unknown. The solar microscope was invented in 1740 and remained popular into the next century. This instrument probably is older than Grinnell College, possibly dating to the late 18th century and certainly no later than the early 19th century.

This "talking machine" is on loan to the museum by the family of Professor Ben Graham. They used it in Massachusetts in the late 1890's. The recording is on a wax cylinder instead of a flat disk. The horn is not original; the original horn was much larger.

This small chronometer, about three inches in diameter, was made by Northwest Instrument Company of Seattle, Washington. The date of manufacture is unknown. It is mounted in gimbals for use on a ship.

This telescope has a mahogany tube and five brass draw sections. It was sold by and probably made by Queen & Co. Date of acquisition is not known

The Seth Thomas clocks, acquired by the college in December of 1888, represent the pinnacle of accuracy in timekeeping within their era. The clocks have very heavy cast-iron frames and gold-plated regulators. The polished brass tubes on either side of the clocks house the weights which maintain the rhythm and accuracy of the clock regulators. The college purchased the clocks after receiving the gift of an 8-inch Clark refractor, along with a chronograph, micrometer and a transit telescope. Grinnell offered practical astronomy classes for the first time in the 1888-89 academic year. Located in Goodnow Hall and used in the Goodnow observatory , the clocks were set respectively for solar and sidereal time. This clock is set for solar time.The second image shows the Goodnow Hall clock room in the early 1900's.  The chronometer is on the table to the right. The clocks, routinely maintained by Kens Clock Repair of Brooklyn, Iowa. still keep excellent time and are on display in the Kistle Science Library in the Noyce Science Center.

The Seth Thomas clocks, acquired by the college in December of 1888, represent the pinnacle of accuracy in timekeeping within their era. The clocks have very heavy cast-iron frames and gold-plated regulators. The polished brass tubes on either side of the clocks house the weights which maintain the rhythm and accuracy of the clock regulators. The college purchased the clocks after receiving the gift of an 8-inch Clark refractor, along with a chronograph, micrometer and a transit telescope. Grinnell offered practical astronomy classes for the first time in the 1888-89 academic year. Located in Goodnow Hall and used in the Goodnow observatory , the clocks were set respectively for solar and sidereal time. This clock is set for solar time.The second image shows the Goodnow Hall clock room in the early 1900's.  The chronometer is on the table to the right. The clocks, routinely maintained by Kens Clock Repair of Brooklyn, Iowa.. still keep excellent time and are on display in the Kistle Science Library in the Noyce Science Center.

This lamp was used by Prof George L. Pierce while studying at Oberlin and given to the museum by Wayne and Clara Denny. Grinnell students used oil or gas lamps until the mid 1890’s.

This telegraph recorder used tape to record dots and dashes. It is missing its stylus.

Sent to Grant Gale at Grinnell by John Bardeen at Bell Telephone Labs in 1950

(No Name)

Has a rotary stage, no eyepieces, and 3 objectives but is one missing.