In resuming consecutively the story of the half-century’s progress of
Harvard College Observatory, which was interrupted in the preceding
number to give place to a biographical notice of Prof. W. C. Bond, it
may be remarked that the period of his official term, which covered 19
years, was fruitful in great discoveries and events in the astronomical
department of science. Harvard Observatory contributed its full share,
though the greatest of all was that which gave fame to Le Verrier, the
French astronomer, the discovery of the planet Neptune. In September,
1844, the observatory building on Summer House hill had been completed
to the extent proposed at that time, and the instruments were
transferred from the Dana house.
A new transit instrument, imported by the United States government
for the use of the Northeastern Boundary Commission, was set up in
December, and used during the winter in observations for ascertaining
the latitude, as previously described in the quotation from Prof.
Peirce. The results were collated and discussed by Prof. Peirce in
the memoirs of the American Academy. These were the first notable
observations of precision at the new observatory. The longitude was
also determined by the most accurate method then known, observation of
occultations and moon culminations and comparison of a considerable
number of chronometers transported to and from Greenwich by ocean
steamers. In the ultimate determination the record made by several
hundred chronometers thus sent to and fro, and observations of
occultations, etc., in Dorchester, Cambridge, Brooklyn, Philadelphia
and Washington, ranging through many years, were brought into the
account. The earliest were observations made in Philadelphia in 1769.
After the laying of the Atlantic cable still closer comparisons with
the zero of Greenwich were possible. The position of the observatory as
finally determined and now officially of record is: Longitude, 71° 7′
44.85″, west; latitude, 42° 22′ 47.6″, north. As showing the error of
the best attainable results by use of chronometers it may be remarked
that by that method the central tower of the observatory was located at
a point on the lawn half way between the front door of the director’s
dwelling house and Garden street. The discrepancy is about 320 feet.
About the time of the first determination Commodore Owen of the British
Navy was making an official survey of the coast of New Brunswick and
Nova Scotia. Having confidence in what had been done at Cambridge
he took that station for his zero in preparing his official report,
ultimate reference being made to Greenwich. The first importation
of chronometers appears to have been made jointly by Prof. Bond and
Commodore Owen. When the report was submitted it was challenged by some
of the British Board of Admiralty, who believed that the longitude of
Halifax was better known. In due course Prof. Bond was inquired of, and
his letter addressed to the board of admiralty, in explanation of the
technicalities, proved convincing and its conclusions were cordially
accepted, with thanks by Admiral Beaufort on behalf of the board.
The officers-in-chief of the United States Coast Survey, and of the
exploring expedition severally adopted the Cambridge meridian as the
zero in preparing their official reports.
A new instrument purchased by the observatory, a 2¾-inch equatorial,
permitted accurate observations to be made of the solar eclipses of
1845 and 1846, the comets of the same years, the transit of Mercury in
1845 and of the newly discovered planet Neptune.
The 15-inch equatorial was set up on June 23 and 24, 1847. Certain
nebulæ and the planet Saturn were the first subjects of study.
Discoveries of importance were made in each field of investigation. The
report of the visiting committee for 1848 notes the discovery by Prof.
Bond on Sept. 19 of that year of the eighth satellite of Saturn, and
speaks of it as “the only addition to the solar system ever made on the
continent of America.”
The few years immediately following the date of the great telescope may
be called the romantic period in the history of the observatory. There
was no instrument on this continent to be compared to it, and it had
but one equal in Europe.
While the director of the observatory kept cool enough to utilize it to
the utmost, he manifestly shared in the enthusiasm. One of the earliest
to inquire what could be seen by it was Edward Everett, president of
the college from 1846. Prof. Bond responded by letter on July 26,
1847, named several matters and ended by saying: “But I must recollect
that you require of me only a brief account of our telescope. The
objects revealed to us by this excellent instrument are so numerous
and interesting that it is difficult to know where to stop.” On Sept.
22 following Prof. Bond wrote to the president: “You will rejoice with
me that the great nebula in Orion has yielded to the powers of our
incomparable telescope.”
He explains the reason for his rejoicing by saying that this nebula and
that of Andromeda had hitherto been the strongholds of the “nebular
theory,” or the theory that the nebulæ are masses of matter in process
of condensation into systems.
Now, the mass in Orion which, he said, had defied the telescopes
of both the Herschels, and, at first, that of Lord Rosse, had been
resolved into innumerable distinct points of light, or separate stars,
by the Cambridge refractor, whose only competitor in the search was
Lord Rosse’s instrument, “the largest reflector in the world.”
The phrase “incomparable telescope” was warranted. Nor does the
didactic suggestion of the proverb about the new broom apply; for
more than 30 years afterwards the present director of the observatory
had occasion to say: “In 1877 besides the photometric measures of the
satellites of Mars, a series of measures for their positions was also
made. The number of these observations was second only to that obtained
with the great telescope at Washington.” Of the work done two years
later, he says: “Of the satellites of Mars 1348 measurements were made,
Deimos being last seen at this observatory as it gradually receded
from the earth. This is remarkable, as our telescope has entered into
competition with the largest telescopes of the world, some of which
admitted two or three times as much light.”
On Nov. 7, 1848, a transit circle was set up and it completed the set
of new instruments at first proposed for the observatory. Previous
to this date two new “comet seekers” had been received, the gifts
respectively of President Quincy and Mr. J. I. Bowditch. With these
in the six years beginning with 1845 the original discovery of ten
comets was made by Mr. G. P. Bond. In his report for 1846 Prof. Bond
says that during that year stellar and lunar observations had been made
in co-operation with like work done by observers of the United States
Coast Survey at West Point, Philadelphia and Nantucket, to determine
longitudes for the purposes of the coast survey.
[Illustration: W. C. BOND’S OBSERVATORY CHAIR.]
But visions of the sky were not the only matters of interest at the
observatory in this early period. The great telescope was poised
at a height of 13 feet from the floor of the dome, and its sweep was
from three degrees beyond the zenith to as many below the horizon.
The visual end of the instrument therefore might need to be set at
any point along an arc of 90 degrees, and an observer would have to
be something of an acrobat in successfully using it unless a suitable
chair could be obtained. There was none in the world that filled all
the requirements, and Prof. Bond invented and made one. It is in use,
unchanged, to this day, and by means of its ingeniously combined
wheels, cogs and pulleys the observer can quickly and easily place
himself anywhere along the vertical quarter circle and horizontal full
circle traversed by the eye-piece of the telescope.
Prior to 1845 a transfer of 12 chronometers to and from Greenwich,
Eng., had been made by Prof. Bond and Commodore Owen, for the
determination of the longitude of the observatory. Other chronometer
expeditions were conducted subsequently in co-operation with the United
States Coast Survey, the final one being in 1855. In the summing up of
results, 723 independent chronometer records were used. The magnitude
of this undertaking, as a whole, surpassed anything ever attempted in
any other country.
In his report, reviewing the year 1848, the director says; “Some
experiments made with the daguerreotype and talbotype processes for
obtaining impressions of the sun’s image formed by the telescope have
not been attended with complete success; however, we do not despair of
ultimate success.”
In the report for 1850 he is able to say: “With the assistance of Mr.
J. A. Whipple, daguerreotypist, we have obtained several impressions
of the star Vega. We have reason to believe this to be the first
successful experiment ever made either in this country or abroad. From
the facility with which these were executed with the aid of the great
equatorial, we were encouraged to hope for further progress.” In the
report of the following year he speaks of pictures of the moon and
stars obtained by this process, and adds with reference to his son’s
official visit to Europe that year: “Some of these daguerreotypes taken
by the aid of our great object glass excited the admiration of eminent
men in Europe, to whom Mr. G. P. Bond gave specimens.” In an official
letter he says of his son’s visit to Paris: “He attended in May a
meeting of the French Academy, and there presented a daguerreotype of
the moon taken with our large telescope.” Other specimens were placed
in the great exhibition of London, or World’s fair, of that year, and a
council medal was awarded for them.
This tour in Europe by the younger Mr. Bond makes an interesting
episode in the general record. He was everywhere cordially received
by men of science, a fact attributable in part, no doubt, to his own
reputation, but more especially to his being the representative of the
new observatory, already of fame, established in the distant West.
On arriving at Cronstadt he was surprised at meeting an officer of
the Russian government who had instructions to conduct him to the
imperial observatory at Pulkova, where, during his stay in Russia, he
was made the guest of the director of the observatory and given all
possible attentions and facilities, including the “great privilege” of
practically manipulating the instruments. Among these was the great
telescope, the rival of the Harvard equatorial. During the tour he
visited Sweden and saw a total eclipse of the sun. Among those from
whom he had friendly receptions were Baron Humboldt, Sir John Herschel,
Sir David Brewster, Sir G. B. Airy, Le Verrier, Biot Argelander, Gauss
and Hansen; also Lord Rosse, whose great telescope he had opportunity
to use.
In July, 1848, the wires of the magnetic telegraph were connected with
the observatory at the expense of the coast survey, for determining by
instant communication the longitude of certain principal cities in the
United States. There are suggestions of both the modern and the antique
world in the statement that in this first experience the electrical
apparatus of a department of the institution founded by John Harvard,
was connected with like apparatus in an observatory in the garden of
Peter Stuyvesant in New York city. These electrical experiments of
the coast survey were begun as early as 1844, between Washington and
Baltimore.
Various improvements of method had been made, and that most approved
was followed on this first occasion at Cambridge. The coast survey
officer in charge had for his assistants Prof. Bond at Cambridge and
Prof. Loomis in New York. An official letter of the electrician of the
Coast Survey Department says: “During these experiments Prof. Bond
conceived the idea of using an automatic circuit interrupter.”
Some question of priority as to this suggestion arose in later years.
It was doubtless a spontaneous and original thought with Prof. Bond,
though the suggestion appears to have been made earlier elsewhere,
but it had not been acted upon “from apprehension of injury to the
performance of an astronomical clock which must be used for the
purpose.” Experience proved eventually the apprehension to have been
groundless; but Prof. Bond’s suggestion avoided any liability of the
kind by proposing that an astronomical clock be made for the purpose.
In August, 1848, he received authority to have such a clock made at the
expense of the coast survey. Reverting to the matter in a subsequent
annual report, Prof. Bond says: “I caused such a clock to be made,
and it is found to answer perfectly the intended purpose. But another
and far more serious difficulty presented itself in the accurate
registry of the beats of the clock after being transmitted by the
galvanic circuit; and it was at this point that further progress in the
application of this method to astronomical observing was arrested.”
[Illustration: DAVID SEARS. The First Donor to the Observatory.]
Experimenters were busy at Philadelphia, Cincinnati, and elsewhere,
during the two years’ interval in attempts to solve this concomitant
problem, and with very considerable success. That none of these devices
quite filled the requirements is manifest by the fact that they did
not go into general use. But the perfected apparatus submitted to the
officer of the coast survey by Prof. Bond, April 12, 1850, did go into
such use. This instrument Prof. Bond stated to be the joint invention
of himself and his two sons, George P. and Richard F. Bond. It was
named at first from one of its peculiar parts, the “spring-governor,”
but the more comprehensive title of “chronograph” was later applied to
it.
While as a piece of mechanism, it was distinct from the “circuit
interrupter,” the two were used conjointly, and thus acting in
combination their operation in recording became known soon afterwards
in England as “the American method.” By this method the errors
suggested by the term “personal equation” are greatly diminished, and a
definiteness of record is attained, which permits the recording sheet
to be read by the eye to tenths and by scale and lens to hundredths of
a second. The successive sheets are the primary official record, and
being bound into volumes, become a part of the permanent archives.
The apparatus was at once put to use in the several telegraphic
stations of the coast survey; and one of the circumstances which made
Mr. G. P. Bond’s tour in Europe a notable one was its exhibition for
the first time there. It was shown in operation and explained in a
lecture by him before the Royal Astronomical Society, and also at
the annual meeting of the British Association for the Advancement of
Science. Through the urgency of Sir David Brewster and others it was
set up in the great exhibition at London in 1851, where a medal was
awarded for it. It had the highest award of the Massachusetts Mechanic
Association, a gold medal. It was adopted at the Greenwich observatory
soon after Mr. Bond’s exhibition of his model, and speedily throughout
Europe.
Soon after the electrical experiments of 1848 at the observatory the
wire was put into use to transmit to Boston and different railway
points, signals giving the true local time, these signals being
electrically responsive to the movement of an astronomical clock in
the observatory, the method of transmission being that of the “circuit
interrupter.” This system was at once adopted in England, wire
connections being made with a clock in Greenwich Observatory. This
time service of the Harvard Observatory, though continued during the
intermediate period, was not organized as at present until 1872.
In 1852 the officers of Harvard Observatory co-operated with Captain
Charles Wilkes in experiments for ascertaining the velocity of sound
under different atmospheric conditions. In these tests cannon were
fired near the observatory, at the arsenal in Watertown, at the
navy yard in Charlestown and at Fort Independence in the harbor,
the central observing point being the cupola of the State House in
Boston, where Captain Wilkes took his station. These experiments had
immediate reference to a reduction into proper form of data obtained
by the exploring expedition, wherein Captain Wilkes had caused surveys
of islands and groups in remote seas to be made by sound. In these
surveys, distances between points whence angles were projected were
determined by the firing of cannon at those points.
In 1855 an endowment of $10,000 was made by ex-President Quincy as a
memorial of his father, Josiah Quincy, a patriot of the revolution.
This fund was specifically applied to the publication of annals of the
observatory. The first volume was issued in 1856 and comprised a review
of the work of the preceding years, so that the series of which it is
the initial number makes a continuous record from the beginning. The
series now numbers nearly 25 volumes. The decease of Prof. W. C. Bond
occurred Jan. 29, 1859.