Part 4

George Phillips Bond was the second director of Harvard College observatory, being the successor of his father, Prof. W. C. Bond. The date of his appointment was 1859. He was born in Dorchester, Mass., May 20, 1825, and graduated at Harvard in 1845. Thenceforth until his decease Feb. 17, 1865, he was in the constant service of the observatory. Prior to his taking the chief office his labors as assistant had gained for him a professional reputation; he had shared with his father the heavy task of organizing the observatory and carrying it on with slender means; he was familiar with its routine, and both by academical and practical training was peculiarly qualified for the position.

His professional record therefore is not to be limited to his own term as director. The computations required in the preparation of the three early volumes of the annals were to a great extent his work, and those pertaining to the chronometric expeditions between Boston and Liverpool, were wholly by him. He was the discoverer of the dark interior ring of Saturn, one of the first revelations of the great telescope, and discoverer also, as already stated, of ten comets within a brief period of years. In this cometary work it was his practice to sweep the whole visible heavens once every month.

His observations of Saturn led to the adoption of a new theory as to the constitution of the rings. During his term systematic observations were made of certain nebulæ, particularly that in Orion. He conducted a series of zone observations of faint stars near the equator, prepared a plan of observation and reduction, and with his own hand graduated the mica scales used in the work.

In 1860 he made an investigation of the brightness of certain celestial objects, including the moon and the planets, the results of which have a special value but are not identified with the Harvard photometrical series of later years, which relates to fixed stars only. During his term the formation of a star catalogue was begun, the observations being made with the meridian circle and in right ascension only, and much progress was made in picturing celestial objects by the camera, the process having, with the disuse of Daguerre’s particular method, gained the generic name of photography.

The prestige of the beginning and early successes of astronomical photography attaches to the administration of the senior Bond; but his son shared fully in the labors of thought, contrivance and manipulation by which the original experiments were conducted, and in appreciation of the future possibilities to science in this new method of observation.

One evidence of this appears in a paper read by the younger Mr. Bond before the American Academy on May 12, 1857, the immediate occasion for its presentation being a most significant discovery made at the observatory a few days earlier.

The paper says: “Daguerreotype images of the star Vega were obtained at the observatory of Harvard College on July 17, 1850, and subsequently impressions were taken from the double star Castor, exhibiting an elongated disc, but no separation of its two components.

“These were the first, and until very recently, the only known instances of the application of photography to the delineation of fixed stars. A serious difficulty was interposed to further progress by the want of suitable apparatus for communicating uniform sidereal motion to the telescope.

“This has been supplied by replacing the original clock of the great equatorial of the observatory by a new one, operating on the principle of the spring-governor. Immediately upon its completion, a new series of experiments was commenced. These have been successful in transferring to the plate by the collodian process, images of fixed stars to the fifth magnitude, inclusive, with singular and unexpected precision. The most remarkable instances of success are the simultaneous impressions of the group of stars composed of Mizar of the second magnitude, its companion of the fourth and Alcor of the fifth magnitude. The following measurements of the angular distance of the companion from Mizar were taken from the plates.”

A tabulated statement follows in the paper, giving dates from April 27 to May 8, with measurements from 13 photographic negatives produced on the respective dates. The mean for distance is 14.49 seconds, and for angle of position, 147°.80. For the same stars observed in the usual way, Struve’s mean of six observations is, for distance, 14.40 seconds; for positions, 147°.40.

Mr. Bond’s comments are: “The photographic method has thus in its first efforts attained the limit of accuracy, beyond which it is not expected the other can ever be sensibly advanced.

“Should photographic impressions be obtained from stars between the sixth and eleventh magnitudes as has already been done for those between the first and fifth, the extension given to our present means of observation would be an advance in the science of stellar astronomy of which it would scarcely be possible to exaggerate the importance.”

Mr. Bond made important contributions to the literature of the science both in its mathematical and practical departments. Among the more notable of the former was a paper on cometary calculations and the method of mechanical quadratures, valuable in various respects, and notable in having anticipated an important improvement afterward given independently by Encke; also a paper on the use of equivalent factors in the method of least squares. He wrote a monograph covering observations of Donati’s comet of 1858, for which he was awarded the gold medal of the Royal Astronomical Society and was the first of his countrymen to obtain that distinction. He began a paper on the nebula in Orion, which he did not live to complete, though during his prolonged last illness he continued his labors upon it, and dictated to an amanuensis long after strength to write had gone from him.

This paper was afterwards finished by Prof. T. H. Safford, then of Harvard, now of Williams College observatory. A biographer says of Mr. Bond: “Science to him was not a pastime but a serious calling, to be pursued with the utmost conscientiousness and singleness of purpose. That he did so much and did it so well, during the few years allotted to him, must have been partly owing to an extreme reluctance to dissipate his powers by beginning new works while the old were still unfinished.” He received the honorary degree of A.M. from Harvard in 1853.

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.

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.

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.

VI.

Edward Charles Pickering, the present director of the observatory, was appointed in 1876. He was born in Boston and is of the Essex family of the name, Colonel Timothy Pickering being his great-grandfather. He is a graduate of the Lawrence Scientific School of the class of 1865. During the next two years he was a teacher of mathematics in that department of Harvard University. Later and up to the time of his appointment as director, he was professor of physics at the Massachusetts Institute of Technology.