HENDERSON, THOMAS,
Professor of Practical Astronomy, Edinburgh.—This distinguished
astronomer was born at Dundee, on the 28th of December, 1798. His
father, who was a respectable tradesman, after giving him the best
education which his native town could furnish, apprenticed Thomas, at
the age of fifteen, to Mr. Small, a writer or attorney, in whose office
his elder brother was then a partner. Here he served a term of six years
with great diligence; and on the expiration of this period he removed to
Edinburgh, to perfect himself in the study of law, as his future
profession. Having obtained a situation in the office of a writer to the
signet, his abilities and diligence attracted the notice of Sir James
Gibson Craig, by whose recommendation he was appointed secretary or
advocate’s clerk to the talented and eccentric John Clerk, afterwards
raised to the bench under the title of Lord Eldin. On the retirement of
the latter into private life, Mr. Henderson obtained the situation of
private secretary to the Earl of Lauderdale, which he afterwards quitted
for the more lucrative appointment of secretary to Francis Jeffrey, then
Lord Advocate, in which office he continued till 1831.
All this was nothing more
than the successful career of a diligent young lawyer, devoted to his
profession, and making it the means of advancement in life; and as such,
his biography would not have been worth mentioning. But simultaneous
with his application to the law, another course of study had been going
on, from which he was to derive his future distinction. It often enough
--too often—happens, that dry legal studies send the young mind with a
violent recoil into the opposite extreme; and thus many a young Hopeful
of a family is
—"Foredoom’d his father’s soul to
cross,
Who pens a stanza when he should engross."
Henderson, however, chose
more wisely, for his favourite by-study was that of astronomy, which he
commenced so early as during the period of his apprenticeship—which he
prosecuted so as not to retard his professional pursuits—and to which he
did not wholly resign himself, until he found that he could do it with
safety and advantage. In Dundee he applied to astronomical
investigations during the leisure hours of his apprenticeship, and
continued in like manner to prosecute them after his arrival in
Edinburgh, where his proficiency in the science gradually introduced him
to the acquaintanceship of Professors Leslie and Wallace, Captain Basil
Hall, and other distinguished scientific men of the northern capital. At
this time it was fortunate for him that an observatory had been erected
upon the Calton Hill, which, though poorly furnished with the necessary
apparatus, had yet enough to satisfy the wants of ordinary inquirers. Of
this establishment Professor Wallace had charge; and finding that he
could intrust Mr. Henderson, though a stranger, with free access and
full use of the instruments, the latter gladly availed himself of the
opportunity, by which he improved himself largely in the practical
departments of astronomical science, in addition to the theoretical and
historical knowledge of it which he had already acquired. These studies
upon the Calton Hill were the more commendable, when we take into
account his weak health, his tendency to a disorder in his eyes, and his
diligence in the duties of his laborious profession, which he had too
much wisdom and self-denial to neglect.
It was not till 1824 that
Mr. Henderson presented himself to notice as an astronomer, which he did
by communicating with Dr. Thomas Young, at that time superintending the
"Nautical Almanac." To him he imparted his method of computing an
observed occultation of a fixed star by the moon, which Young published
as an improvement upon his own, in the "Nautical Almanac" for 1827, and
the four following years, to which Henderson added a recent method and
several calculations. These methods were also announced to the
scientific world by being published in the "London Quarterly Journal of
Science," while Mr. Henderson received for them the thanks of the Board
of Longitude. In 1827 he communicated a paper to the Royal Society of
London, "On the Difference of Meridians of the Royal Observatories of
London and Paris," which the society published in its "Transactions."
Mr. Henderson’s reputation, as a scientific and practical astronomer,
was now established, while his communications to Dr. Young were about to
change his public career in life for one more congenial to his favourite
pursuits. The latter, who held the important office of secretary to the
Board of Longitude, died, and after this event a memorandum was found in
his hand-writing, which he had deposited with Professor Rigaud, desiring
that, on the event of his death, the Admiralty should be informed that
no one was so competent, in his opinion, to succeed him as Mr.
Henderson. The Admiralty were pleased to think otherwise, and appointed
Mr. Pond, the Astronomer-Royal, to the charge. Soon after another
important vacancy occurred by the death of Mr. Fallows, who had charge
of the observatory at the Cape of Good Hope; and on the Admiralty
offering it to Mr. Henderson, he closed with the proposal, and repaired
to the Cape in 1832, although it was to sojourn among strangers, and
with a disease of the heart, which, he knew, might at any time prove
fatal. His scientific exertions during his short residence at the Cape
of Good Hope, attested his self-devoted zeal in behalf of astronomy;
for, independently of his official duties, the mass of observations and
calculations which he had stored up, would have sufficed for the
lifetime of a less earnest astronomer. Such incessant labour proved too
much for his constitution, and in little more than a year he was obliged
to return home, where, fixing his residence in Edinburgh, he devoted
himself to the task of arranging the large mass of valuable materials
which he had collected at the Cape. While he was thus employed, an
agreement was entered into, in 1834, between the government and the
Astronomical Institution of Edinburgh, by which the Institution agreed
to give up the use of their observatory on the Calton Hill to the
University, while the government engaged to convert it into a public
institution, furnish it with suitable instruments, and provide for an
observer and assistant. This movement made it necessary to fill up the
professorship of practical astronomy, which had been vacant sixteen
years; and on Lord Melbourne applying to the Astronomical Society of
London for advice upon the subject, Mr. Henderson was recommended to the
chair, to which he was appointed, with the honorary office of
Astronomer-Royal for Scotland, being the first that had held it. Having
thus obtained a situation that realized the beau ideal of his
ambition for scientific distinction, opportunities of study, and means
of comfort, he, in 1836, married Miss Adie, eldest daughter of Mr. Adie,
the talented inventor of the sympiesometer.
Hitherto we have scarcely
alluded to Professor Henderson’s astronomical writings, upon which his
fame depends. A list of these, however, amounting to upwards of seventy
communications, has been published in the "Annual Report of the
Astronomical Society for 1845." To these also must be added his five
volumes of observations from the Calton Hill, which were made between
the years 1834 and 1839, as well as the selections from them which were
given to the world after his death. To all this labour, the exactness,
and, in many cases, the originality of which is more wonderful than the
amount, great as it was for so short a life, he brought that methodical
diligence and application which he had acquired in youth at the desk of
a writer, and through which he became a prosperous lawyer. It was not
merely in astronomical calculation that he excelled; the different
departments of natural science also had occupied his studies, so that at
different periods he was enabled to supply the places of the professors
of mathematics and natural philosophy in the University of Edinburgh.
His death, which was sudden, and occasioned by that disease of the heart
under which he had laboured for years, occurred on the 23d of November,
1844. |