Joseph Winlock was the third director of Harvard College observatory,
being appointed in 1866. He was born in Shelby county, Ky., Feb.
6, 1826; he graduated at Shelby College in 1845, and was professor
of mathematics and astronomy there until 1852. He was subsequently
in the service of the Naval Observatory at Washington, and, still
later, instructor in mathematics at the Naval Academy at Annapolis.
At different dates, he was superintendent of the work of preparation
of the Nautical Almanac. He continued in office as director of the
observatory until his decease, June 11, 1875.
His administration appears by the record to have been one of various
activity. A large amount of improved apparatus was added to the
resources of the observatory, partly by purchase and partly by
invention and making on the spot. He kept up the reputation of the
observatory, which has never failed from the start, for originality
and ingenuity in mechanical devices. It was during his term that the
transmission by electricity of the true solar time to railroad centres
and business points in all parts of New England became a regular
part of the observatory work, and, by the system which he organized,
compensation was made by corporations and individuals whose clocks were
put into electrical connection with that at the observatory.
A considerable revenue has thus annually been derived. Other
electrical apparatus of the observatory was modified and improved. A
“switch-board,” the device of his predecessor was much elaborated in
its mechanism, whereby the electrical current was made more available
and all the principal instruments were connected at will with the
chronographs.
In 1868 when he visited Europe he procured the apparatus of a meridian
circle of the latest device, the lenses being made in Cambridge. In
setting up the instrument he saw opportunity to introduce various
improvements in mechanism.
These were approved by experience and went into general use elsewhere.
Another of his devices was “for the determination of absolute
personal equation by mechanical means.” Other contrivances, either
wholly original or ingenious modifications of known apparatus, were
an attachment to the spectroscope for automatic recording, being a
modification of the chronograph: a combination of a stationary plane
mirror with a fixed lens of great focal length—from 30 to 40 feet—for
photographing the sun; a later improvement of this, by which the
telescope was reduced to a single fixed lens of long focus and small
aperture, chromatic aberration was avoided and the image on the plate
could be made as large as was convenient for measuring; and a change of
method by which the sun’s image could be taken at the principal focus
of the object glass and not beyond an eye-piece used to enlarge the
image.
In February, 1866, when he took charge of the observatory, the great
equatorial was applied to a series of observations of double, and
especially binary stars. This investigation was continued as steadily
as circumstances would permit till 1872, and the results appear in the
annals. In 1867 the first spectroscope owned by the observatory was
imported, and in 1869 another. Two small direct vision spectroscopes
were also procured during Prof. Winlock’s term.
In 1870 the new meridian circle, a superior instrument, was set up,
and on Nov. 10 of that year was begun the series of observations for
position of stars in the “Cambridge zone,” so called, or that between
50° north and 55° north and overlapping 10′ upon each contiguous zone.
This survey was a joint enterprise conducted by certain of the great
observatories of the world, that of Harvard being one of the two in
this country having a share in the work. On July 4, 1870, was begun a
series of photographs of the sun, and the work was continued nearly
or quite to the end of Prof. Winlock’s term, many hundred photographs
being comprised in the list.
[Illustration: HARVARD OBSERVATORY STATION IN SPAIN.]
In September, 1871, was begun an elaborate investigation of lunar
phenomena, which continued a year. In 1871 an arrangement was made with
the coast survey by which a series of photometric observations was
carried through, and for this a Zöllner astro-photometer was imported.
The work was continued three years, though not all of it at Cambridge.
The results are in the annals in 1878. The standard in using this
instrument was an artificial star produced by lamplight.
During this term two expeditions were made with apparatus for observing
total eclipses of the sun, and in both satisfactory results were
obtained. On the first occasion, of date Aug. 7, 1869, the station was
at Shelbyville, Ky., and on the second, of date Dec. 22, 1870, at Jerez
de la Frontera, in Spain. In 1867 daily observations in terrestrial
magnetism were made at the observatory for the purposes of the coast
survey. In March, 1869, experiments for determination of longitudes
were conducted on a continental scale, wire connection by relays being
made with San Francisco. In these experiments apparatus which had
been modified by Prof. Winlock was used and by this method, and also
by another which was applied, it proved that the time of passage of a
signal from Cambridge to San Francisco through the wire and six relays
was very nearly three-quarters of a second. Between Dec. 13, 1869, and
the summer of 1872, electric signals were sent by the Atlantic cable to
and from Brest in France, via Duxbury, Mass.
The purpose of these tests was to establish with precision the
difference of longitude between America and Europe. Prof. Winlock
supervised the work of preparing and engraving a series of plates
illustrating remarkable celestial objects. These gave special value to
the volume of annals in which they appeared, causing an unprecedented
demand for copies, so that it is now a rare book. His publications were
not numerous, but there is no doubt that his scholarship, versatility
and wide experience would have yielded valuable additions to the
literature of science had his life been prolonged.
The means at command during his term did not warrant the publication of
many volumes of annals. Though for nearly 10 years in office he did not
live to see any of his own observations published or even to complete
the work of his predecessors.
[Illustration: PROF. JOSEPH WINLOCK.]
During the term the permanent funds of the observatory were increased
by the bequest of James Hayward $20,000, and that of James Savage
$20,000. In 1870 a subscription of $12,450 was completed for purchase
of a new meridian circle. In the preceding term a gift of $10,000 was
made by William Sturgis for the publication fund. Prof. Winlock had the
honorary degree of A.M. from Harvard in 1868.