The Story Behind the naval observatory's Seal
RADM Charles Henry Davis, Superintendent, USNO (1865 - 1867, 1874 - 1877)
From Astronomical and Meteorological Observations Made at the U. S. Naval Observatory During the Year 1865 (Washington, 1867)
The Astronomer Royal, at Greenwich, is directed by his warrant of office "to apply himself with the most exact care and diligence to rectifying the tables of the motions of the Heavens, and the places of the Fixed Stars, in order to find out the so-much-desired longitude at sea; for perfecting the Art of Navigation;" and the original inscription over what was the principal entrance-door of the Observatory, reads "Carolus Secundus, rex optimus, astronomiae et nauticae artis patronus maximus, speculam hanc in utriusque commodum fecit." -- (Regulations of the Royal Observatory, Greenwich, I. 1.)
The Astronomer Royal, in his Ninth Report to the Board of Visitors of the Royal Observatory, says: "The history of the circumstances which led the Government of the day to supply the funds for the construction of the Observatory, shows that but for the demands of accurate lunar determinations, as aids to navigation, the erection of a National Observatory would never have been thought of." The date of this report is November, 1843. This view is frequently repeated in his subsequent reports. He says in his report, in January, 1847: "Greenwich Observatory was built mainly for observations of the Moon, and of stars regarded as accessories to lunar observations;" and in his report, in June, 1864, he says "it was mainly for observations of the Moon that the Observatory was founded."
Thus it was the demands and the study of navigation "gubernandi studium" in the 16th and 17th centuries -- making it a matter of great importance to possess the means of accurately determining the longitude at sea -- which led to the cultivation of astronomy as a national object.
Dr. Whewell observes that besides the advancement of astronomy, there were other reasons which urged on, with a stronger impulse, the application of the Newtonian theory to the Moon. A perfect lunar theory, he adds, promised to supply a method of finding the longitude of any place; and so the verification of the theory was identified with an object of immediate practical use to navigators and geographers. "A good method for the near discovery of the longitude had been estimated by nations and princes at large sums of money. The Dutch were willing to tempt Galileo to this task by the offer of a chain of gold. Philip the Third, of Spain, had promised a reward for this object still earlier; the Parliament of England, in 1714, proposed a recompense of £20,000 sterling; the Regent Duke of Orleans, two years afterward, offered 100,000 francs for the same purpose. These prizes, added to the love of truth and of fame, kept this object constantly before the eyes of mathematicians during the first half of the last century." -- (Inductive Sciences, Book VII, Chap. IV, Sec. 2d.)
Grant, also, in his History of Physical Astronomy, says, "the method of lunar distances which offers such advantages in finding the longitude at sea, rendered an accurate knowledge of the Moon's motion peculiarly desirable." He then enumerates and comments upon the lunar tables of Clairaut, D'Alembert, Eulers, Maclaurin, and finally upon those of Mayer, of which he says, "these tables were found to come within the limit of accuracy fixed by the Board of Longitude of this country; and a recompense of £3000 was in consequence awarded to the widow of Mayer." -- (Hist. of Phys. Ast., p. 46.)
Here again, it appears that the "gubernandi studium" has led not only to astronomical observation, but to the study of celestial mechanics. The observations which have now been continued systematically for more than a century at the Observatory of Greenwich hold the same fundamental relation to the complete development of the Newtonian theory of gravitation that the observations of Tycho Brahe did to the discoveries of Kepler; and the Greenwich collection, as has been already said, owes its origin and continuance to the demands of a maritime nation for improvements in navigation. This idea, which is succinctly expressed in the motto of the seal, is supposed to be conveyed by the figure of Urania ascending and reaching up with the globe in her outstretched hands, in which attitude she appears to be the suitable and emblematic guide, by whom the way to unite the sky and the ocean is pointed out. [It may be said, in passing, that this Observatory also owes its origin entirely to those wants and uses of the Navy that pertain to navigation.]
The seven stars not only symbolize the starry Heavens, but represent the seven planets of the ancients, and thus unite us with the very earliest periods of Chaldean Astronomy.
The mystical meaning of the number SEVEN which is supposed to be consecrated in nature, as it certainly is in Scripture, is not forgotten. It is assumed that there are seven principles of the mind; there are seven principal tones. Newton discovered seven primary colors. In the earliest systems of the world, the order of the planets, beginning with the most remote, is Saturn, Jupiter, Mars, the Sun, Venus, Mercury, and the Moon. At a later period, the received systems placed these seven luminaries in the seven spheres. The order in which the names of the planets are assigned to the days of the week, beginning with Saturday, is Saturn, the Moon, Mars, Mercury, Jupiter, Venus; and this period has gone on, without interruption or irregularity, from the earliest recorded times to our own days, traversing the extent of ages and the revolutions of empires.
La Place says of this period, which was in use among the Arabs, the Jews, the Assyrians, and throughout all the East, "Qu'elle est le plus ancien monument des connaissances astronomiques." [Précis de l'Histoire.]
In Scripture, the abstract idea of the number seven is completion, fullness, perfection. Arch-Bishop Trench says, "Even the most careless reader of the Apocalypse, must be struck with the manner in which almost everything there is ordered by sevens." -- (See Introduction I. 20.*). He explains the special significance, the sacredness, and peculiar dignity of seven, and of what it is the signature. "There is no doubt that it claims, throughout Scripture, to be considered as the covenant number, the sign and signature of God's covenant relation to mankind, and above all to that portion of mankind with which this relation is not potential merely, but actual-namely, the Church." He carries the evidences of this back to the very beginning of things.
It is not worth while to pursue the subject any further, except to show how aptly the motto and its context convey, in concise language, the idea that the study of navigation led up to the stars, and united the sea with the skies. This motto is taken from the Fourth Book of the Astronomica of Manilius, the subject of which is the influences of the Celestial Signs, or Signs of the Zodiac, upon the morals, affections, tastes, and pursuits, of those who are born under them; or elementary Judicial Astrology.
To those born under the sign Pisces, he ascribes a love of the sea, of ships, of nautical arts, of the physical geography of the sea, and of whatever relates to the practice of the pilot. In the course of this exposition, he introduces the following lines:
"Adde gvbernandi stvdivm: pervenit in Astra - Et Pontvm Caelo conivnxit."
It does not detract from the suitableness of the motto that it is found in an astrological work, written at a time when astrology was astronomy. The following translation supplies the context:
Those who are born beneath the Fishes twain,
Will love the deep, nor dread the dangerous main.
The ship they build, or shape the mast and oar,
And fit their tossing home with varied store.
Hence arts unnumbered, and the myriad throng
Of parts that to the humblest bark belong.
Then, too, the pilot's care: the stars are scaled,
And sky with ocean joined.
I am indebted to my friend, Professor Geo. M. Lane, of Harvard University, for the motto of the seal. The seal has been enlarged and engraved for a book label, as in the plate. It is partly inclosed in a wreath of wheaten blades and ears. This addition to the device is taken from the wheat ears in the hands of the Virgin, (Spica Virginis.) It derives a further interest from being employed as the type of peace and plenty on the national coin, and from Spica Virginis being a nautical star.
*Epistles to the Seven Churches by Arch-Bishop Trench (then Dean of Westminster) 1661.