George Everest.

A series of letters : addressed to His Royal Highness the Duke of Sussex, as president of the Royal Society, remonstrating against the conduct of that learned body. online

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Online LibraryGeorge EverestA series of letters : addressed to His Royal Highness the Duke of Sussex, as president of the Royal Society, remonstrating against the conduct of that learned body. → online text (page 12 of 13)
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necessary to see the method tried it is necessary to see the
whole results, as they stand registered in the old books of the
day, to judge of the accuracy of this opinion : I have done so,
and satisfied myself; but in the present instance, the only
method that appears feasible to me is, to take the results, either
published or in manuscript, as far as Colonel Lambton's part of
the arc is concerned, and those published in my book, pp. 121
to 124, as far as mine are in question.

The former will be found in the manuscript copy of the volume
of the General Report which I forwarded to the India House
from Calcutta, in 1832: as to the latter, though in 1824-5 I
followed precisely in the steps of my predecessor, because I
could not at the time devise a better method, yet I have since
taken the only feasible mode of applying a remedy, by re-
measuring the Sironj base with the compensation bars, and
intend to treat the Beder base in like manner, which is one of
the reasons of my present detention in India.

Thus the arc between Sironj, in latitude 24 7', and Dehra
Dun, in latitude 30 15', already stands quite independent of the
former unit, as also does the longitudinal series originating from
the Sironj base, and terminated by the Calcutta base ; and if I



134

live to fulfil my intentions above alluded to, the arc between
Beder and Sironj will be in a like predicament, whereby all work
executed by me or under my orders will stand entirely free from
the doubtful unit of former days. The work to the south of
Beder, and between it and Cape Comorin, was all performed by
Colonel Lambton before I joined the department in 1818, and
I am in no wise concerned in it : it may be rendered independent
of the rusty accident, by considering the line divided into two
sections, one beginning at Beder and terminating at Doda-
goonta, the other beginning at Dodagoonta and ending at
Pallamcotta, for the latest of these bases is dated 1809, or
about four years prior to the occurrence ; but then Ramsden's
bar must be referred to, and Ramsden's accuracy taken as
infallible. Moreover, there is another source of embarrassment.
I have caused the whole of the angles of principal triangles
between Beder and Sironj to be remeasured with the instru-
ments which I brought out with me to India, because the others
were not so accurate as I liked ; and it appears that every
vestige of Colonel Lambton's Beder base has been erased by the
wilful inhabitants, so that the old and new units will still con-
flict; and though genius may, for aught I can say, devise some
wonder-working method to meet the occasion, yet it surpasses
me to think of any other mode of reconciling the incongruity,
than the simple one of measuring the Dodagoonta and Pallam-
cotta bases over again with compensation bars.

This I decidedly have no intention of doing. I have long been
convinced of how ill personal sacrifices are appreciated, and I
make no more ; therefore in the course of instructions to which
the learned Quartette subject Major Jervis, I beg to point out as
one item the necessity of learning how to measure base lines
with compensation bars, and how to practise that operation in
India.

That part of the subject relating to the old unit may now, I
presume, be considered as disposed of; and it will be clearly
seen that I intend to extricate all operations with which I am in



135

any wise concerned from connexion with that dubious element,
and how ; we may therefore proceed, without apprehension of
confusion, to the unit of reference introduced since 1830.

Compensation-bars and microscopes are, as is well known, the
invention of Colonel Colby. I learned the use of them from my
friends Captain Drummond and the late Captain Murphy, of
the Royal Engineers, to whose kindness I am more indebted
than I can express for the very obliging manner in which they
came to assist me through my difficulties, and point out the
details of the operation, when I was engaged in trying those
made for the E. I. Company, in Lord's Cricket Ground, St.
John's Wood Road.

This apparatus, then of but recent introduction, was copied
from that of the Irish Survey ; and gentlemen who desire more
precise information regarding that placed by the E. I. Company
at my disposal, are referred to the last printed volume of the
Researches of the Asiatic Society of Calcutta, 1831, wherein
will be found the substance of a lecture which I delivered to
that Society on the subject.

That lecture will explain the nature of the whole apparatus as
it stood before use, and shortly after its arrival in India. It has
since been used on four different occasions in the field, an
account of which will appear in my next work, if I live long
enough to complete and publish it, wherein will be described
divers little convenient additions which experience has showed
to be suited to the localities of India.

The principle, however, is quite unaltered ; and Sir John
Herschell need not, I presume, be informed by me that it
involves two scales, each requiring reference to the unit of
measure.

First: The iron standard of ten feet, to which the distance
between the dots marked on the tongues is referred.

Second : The brass scale of six inches, to which the compound
microscopes are referred ; and if any precaution has really been
omitted in establishing these two corrections, let us proceed to
examine to whom the blame of such neglect is attributable.



136

The Court of Directors, at my recommendation, had two iron
standard bars of ten feet, marked A. and B., as also two six inch
brass scales, similarly characterized, constructed by Messrs.
Troughton and Simms. These were just ready at the time I
was making my preparations to leave the land of my birth, when
I had to revise the sheets of my book then in the press, to attend
to the trial measurement, to superintend the construction and
dispatch of invoice upon invoice of new pattern instruments,
recently made for my department, and to give directions about
the supply of such later additions and improvements as were
necessary to make my base-line apparatus on a par with Colonel
Colby's.

This list may almost compare in length with, and was quite as
distracting as r that of the projects contained in the Address
signed by the thirty-eight learned Fellows ; and as there is a
point beyond which human endurance cannot be taxed, therefore
it so happened that from absolute want of time, I could not
compare my standards with those of Colonel Colby, which would
have been the more difficult, as (unless my recollection fails me)
the latter were at Dublin at the time.

I mentioned these facts to the Chairman, my excellent friend
Mr. Loch, and obtained his sanction to leave the standards B
of both the iron bar and brass scale in England ; wherefore, under
the full assurance from Captains Drummond and Murphy, and
Mr. Simms, that they would take prompt and decisive measures
to effect the necessary comparisons previous to the early dispatch
of those duplicates to Calcutta, I deposited one of each, marked
B, in the workshop of Messrs. Troughton and Simms, and
caused only the two marked A to accompany me to India. I
left England in June 1 830, and it was not until the fall of the
year 1834 that the standards B came to my Head Quarters in
Upper India, whither they were dispatched immediately on land-
ing. I have repeatedly made this a subject whereto to draw the
attention of the Government of India, my only legal channel of
correspondence with the India House; and there cannot be a



137

doubt that if in this period of more than three years any shadow
of the interest now so vehemently expressed had actuated the
learned Baronet, he might, on application to Mr. Simms, have
attained the end in view, or if my assumption be groundless, and
that learned gentleman really had in that long period a pure
and disinterested wish to promote the branch of science which
he now has led the world to believe that he so earnestly desires
to patronize, one word from a person of his high fame, addressed
to Dr. Wilkins, Captain Horsburg, Colonel Salmond, Mr. Loch,
or Mr. Edmonstone, would certainly have sufficed to obtain for
him access to those documents which contained the expressions
of my regret at the delay, and my instances pointing to the
urgency of the comparison.

I submit to your Royal Highness that it is really too much,
after having neglected so fair an occasion (if indeed it has really
been neglected, which I now see reason to fear is but too true),
to call on the Court of Directors to send their standards on a
second voyage across the sea for comparison ; for what hope can
be rationally entertained, that if this second opportunity were so
complaisantly afforded, it would be availed of more than the first
long interval, during which my department has been kept in
suspense, and I have been buoyed up with the fallacious hope
that all was in train to completion ?

That all which depended on me has been faithfully effected
will be made very plain if my work should ever see the light, for
then not only the various parts of the process will be identically
noted, but the modes of comparison, and the diverse arrange-
ments and details of the apparatus will be fully explained, which
I venture to surmise will then be pronounced by all persons
competent to judge, as equally perfect in theory, and unobjec-
tionable in the application ; but as I do not desire to anticipate
more than is necessary upon that work, which it is not usual to
require of any person, I shall briefly state such particulars as are
indispensable to substantiate what I here advance :

First : Iron standard bars B and A were compared by me
and Captain Wilcox, 1834-5, by a numerous set of trials.



138

Second : Brass standard scales B and A were compared
under my own eye, by competent persons of my instructing by
a sufficiently numerous set of trials in 1835.

Third : The standard and measuring chains containing all that
is known and all that is dubious of the old unit, as also many
other chains, were compared in 1832 with ten lengths of the ten
feet iron standard A, by Captain Wilcox and myself by a
numerous set of trials.

I submit to your Royal Highness that the ground may now
be considered clear of the subject of the unit of measure ; that
it is no longer to be questioned that all which lay in the power
of the Court of Directors or me, their humble agent, has been
attended to ; and that it is unfair, most unfair, in the thirty-eight
learned Fellows, and particularly in Sir John Herschell, to give
to the world an Address which, though it does not deal in direct
accusation, tacitly implies a censure of omission. What, if I left
such an insinuation undenied, must my scientific brethren in
foreign lands, or even my own countrymen who chance to read
the Address, think of me, but that my work, which has cost me
so much pains, is hollow to the core ? What must be the first
impression on the minds of the Court of Directors, in face of the
recorded opinion of so many gentlemen so celebrated for their
learning, but that I have neglected my business, and made a
bad return for their confidence ?

These impressions never could for a moment have been en-
gendered if I had been present to speak for myself: to my
absence therefore they owe their origin ; and since when, I
pray your Royal Highness, has it become an English fashion of
thinking, that absence is a sufficient plea for a multitude to
combine to injure one ?

We may proceed to the next point of the learned Baronet's
recommendation, which relates to the thermometers ; and here
we shall find but little difference from what has preceded in my
remarks on the comparisons of standards, for, with the exception
of leaving the standard B in England, which was not done, and



139

fortunately not, as there is no reason to suppose that the measure
would have been more profitable than on the occasion of the
former, both cases are precisely similar.

Though it had not been the practice of my predecessor or
myself prior to 1825 to compare our thermometers with any
standard, yet when I returned to England in 1826 I found the
necessity for such comparison was a generally received truth ;
and indeed, considering the intimacy between myself and Capt.
Kater, Mr. Babbage and Mr. Troughton, and the frequent
opportunities which I had of comparing notes with the well
informed gentlemen with whom I have so often sat in the Council
of the Royal Astronomical Society, it is hardly to be imagined
that, wide-awake as I have always been, and disposed silently to
treasure up all valuable hints, I should have been so insensible,
as Sir John Herschell is pleased to suppose me, to what was
passing, and what was for the benefit of my future operations.

To whom I originally owe the conviction of this necessity I
would not take upon myself to say, for I do not remember ; but
this I can distinctly and positively state, unless my recollection
misleads me most strangely, that I do not owe an idea on that or
any other subject connected with my professional pursuits to Sir
John Herschell.

However, it will be satisfactory to your Royal Highness to
know that there were two standard thermometers, A and B, con-
structed by Messrs. Troughton and Simms in 1830, with which,
since October of that year, all others, prior to use in the Great
Trigonometrical Survey of India, have been compared, by sus-
pending them side by side in a room closed during the night and
opened in the morning for the purpose of having them read off;
and if there be any more certain mode, it might have been more
nationally honourable to have communicated it to me than to
await the period when the portions of the work which most need
delicacy were at an end, and the mischief arising from a faulty
method had become irremediable. What are the learned Ba-
ronet's words in the Address? " To fix the zero errors of division



140

of all the thermometers used in every part of the process under
Major Jervis's direction ;" and is it not a legitimate conclusion,
that herein all which Col. Lambton or myself had accomplished
is destined to be swept off as rubbish, and as infinitely inferior
in importance and accuracy to the wonders which Major Jervis is
to bring to pass ? It is manifest that to render my comparisons
as complete as they can ever be it is necessary to compare my
standards A and B with others in England can Mr. Simms
supply those data ? Learned gentlemen who can go to Somerset
House, can, it may be presumed, go to Fleeet-street and as-
certain.

The only point in which Sir John Herschell speaks in this
Address with a semblance of common respect for the accuracy of
the Great Trigonometrical Survey of India, and the wakefulness
of those who conduct it, is that wherein he advises that an arc of
longitude comparable to Lambton's meridional arc should be
measured trigonometrically ; for therein he does, by using the
words " if it has not already been done," admit the possibility
that something may have been accomplished of which he is not
aware, from the mere unaided mother-wit of those who rule
India, and the humble instruments they employ.

This at least is condescension, such as it is ; and considering
the quarter whence it emanates, is deserving of encouragement ;
wherefore I solicit the favour of your Royal Highness to allow
me to acquaint Sir John Herschell that a Longitudinal Series,
originating in the Sironj base, and terminated at Calcutta, was
carried on during my absence in England by Mr. Olliver, an
uncovenanted servant of the E. I. Company, then principal Sub-
Assistant, and now chief Civil Assistant of the Great Trigonome-
trical Survey of India, under certain instructions which I drew
up to meet the wishes of my superiors in authority before sailing
for England in 1825:

That another Longitudinal Series, diverging from the side
Burgapali to Baktapur, two stations just above the Beder base,
(formerly written Boorgapilly and Baukthapoor,) was commenced



141

by me in October 1822, as it is notified would happen in the
extract from Col. Lambton's report of that year, and has since
been completed in very superior style by Lieut. Jacob, of the
Bombay Engineers; a gentleman, who though seemingly un-
known to Sir John Herschell, is highly esteemed for his talents
practical as well as theoretical in my department, into which it
is a high source of pride to me that I was instrumental to his
introduction.

There is also a Longitudinal Series originating from Madras,
which crosses the Great Arc Series, and unites the eastern and
western coasts of the Peninsula, which was executed entirely by
Col. Lambton some years before I joined the Great Trigonome-
trical Survey of India.

Of these, as far as bases are concerned, the first mentioned
already depends on two bases measured with compensation bars,
and is entirely disentangled from all connexion with the old
unit; the second will, if I live to fulfil my intention, be also free
from that dubious element, because, when the compensation bars
shall have been employed in the measurement of a new base-
line in the Beder Valley, the line Burgapali to Baktapur, being
common to the series of the Great Arc and the Western Longi-
tudinal Series, will also depend on the unit of reference of that
apparatus; but then there will still remain another source of
distraction ; for the base of verification of this Longitudinal Series
was measured with a steel chain by Dollond, in the Karleh
plains, under the auspices of Capt. Shortrede and Major Jopp,
whilst I was still in England, and unable to prevent the mischief
taking place ; and though I subsequently caused that chain to
be sent round to Calcutta, and there compared it with my iron
standard A in terms of which it is as well known as a chain can
be, (so at least I think I have made it appear in the book which
I have for some time been engaged in writing,) yet as I am one
of those who think the steel chain a very uncertain implement of
measurement, it will not be matter of surprise that I should for
that and other causes look on the remediation of this as another



142

of the advantages likely to be derived from the course of instruc-
tion of Major Jervis by the learned Quartette having compen-
sation-bar measurements as one of its components.

As to the Longitudinal Series third in the order above enume-
rated, it obviously depends for its cure on the unit of former days ;
and as the learned Quartetto and Sir John Herschell in chief
have displayed so ardent a desire to undertake the management
of the affairs of the Great Trigonometrical Survey of India, it is
most gratifying to me to be able to say, that I shall leave the
ground quite free for them and their pupil to operate on, and
that many of my present assistants will most probably see the
prudence of following the same course.

Though I have sufficient sample of what little weight will be
attached to any opinion of mine, yet it is but justice that I should
state that, of the three Longitudinal Series, I am disposed to
think those portions executed by Lieut. Jacob are by far the best
that Officer is an excellent observer, and distinguished for his
facility of applying what he knows, which is of a high order,
and of no small extent; and as the instrument which he has used
(by Dollond) is a good one for its size, furnished with three mi-
croscopic micrometers to the horizontal circle, he has had greater
advantages than were at the command of those who conducted
the other parts of these three Longitudinal Series.

After the discussions respecting operations of this nature in
Bouguer's work Sur la Figure de la Terre, and many others, but
chiefly the later operations on the Parallele Moyen, it might, one
would think, have been supposed, more especially as the measure-
ment of arcs of longitude by the instantaneous extinction of blue
lights is so palpably pointed out by Col. Lambton in the Asiatic
Researches, and the experiments made by Capt. Drummond
on the obscuration of his magnificent lights with this object in
view, of which I was a spectator, it might, I submit to your Royal
Highness, have been imagined that we were not all so fast sunk
in somnolency and oblivion in India as to need having rockets
pointed out to us as a possible scheme.



143

If originality of idea be claimed by Sir John Herschell in this
case, I am truly sorry to be necessitated to disturb so pleasing a
dream by holding a taper to the eyes of the dreamer, but in
truth this is one of the subjects which was frequently discussed
by Col. Lambton and myself; and rockets, mortars, explosion
of powder, or fire balloons held by stay ropes, sudden extinction
of blue lights, were too familiar to our thoughts to need being
pointed out by the learned Baronet.

The most superficial examination will show immediately that,
except in clear weather, rockets cannot be seen at twenty miles
off with the naked eye,' that their flight is much more unsteady
and uncertain than that of a shell fired perpendicularly from a
mortar would be, and therefore they are more peculiarly liable to
the objection which arises from the utter impossibility of bringing
them at their instant of explosion into the field of a telescope
of sufficient power, an advantage, therefore, which is clearly all
on the side of the explosion of powder, and the sudden extinction
of a blue light, or, what is better, a Drummond's light standing
in a fixed position on the Earth's surface.

Now the only weather in which we can at all calculate on
meeting with very clear nights fit for observing terrestrial objects
with the naked eye is the rainy season, which may be tried by
those who choose in spite of experience to martyrize themselves ;
but the utter impossibility of succeeding in the unhealthy tract
where the Northernmost or Calcutta Longitudinal Series runs,
ought I think in common humanity to preclude that Series from
any such abortive attempt, especially seeing that the firmament
is at this season I speak of almost always obscured by clouds,
which would frustrate all efforts to ensure accuracy of time,
the very element most essential to make the result at all worth
seeking.

Neither the Bombay nor Madras Longitudinal Series seems so
objectionable on the score of unhealthiness as that of Calcutta ;
besides which, generally speaking, they both furnish longer dis-
tances; here therefore is an ample field; and when I have finished



144

my present business which detains me in India, and it is deci-
dedly settled by experiment what method furnishes the best
prospect of success, I shall watch the result with great interest,
and only hope that sufficient precaution will be taken to avoid in-
accuracy of registry, and jumping at conclusions, without which
all the expense of money, labour, and human life will have been
incurred in vain.

I remark, please you Royal Highness, that the learned Ba-
ronet proposes a sector as the fittest instrument for observing
latitudes on these occasions ; but it seems to have escaped his
recollection, if indeed it was ever deemed worthy of his conde-
scending regard, that the Court of Directors have had two three
feet verticle circles constructed to supply the place of the zenith
sector formerly used by Col. Lambton and myself. This is the
less to be expected, as the subject is particularly adverted to in
p. 3 of the Introductory remarks to my book, but it only fur-
nishes one more instance in proof of what I have so often ad-
vanced, that it is quite useless to expect Learned Gentlemen will
take the trouble to search for facts when their high fame enables
them to dispense with such needless reference.

Now, at any rate, at each of the extremities of the total arc
between which the difference of longitude is to be determined by
observation of the phenomenon, the time must be known with
extreme accuracy, which cannot be done without a transit in-
strument well sheltered ; hence two transit instruments and a
zenith sector are necessary appendages to the learned Baronet's
scheme, besides two astronomical clocks.

The three feet circle answers the double purpose of observing
transits and vertical arcs in the plane of the meridian for lati-
tudes, so that by the use of these, one instrument, and that not
the least cumbersome, would be eliminated. Thus, a reference
to my book, p. 3, would have saved the learned Baronet from
recommending an unnecessarily complicated and expensive ma-
chinery ; for it is yet to be shown that complexity is an advan-
tage ; and perhaps if he will be so condescending as to look into


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Online LibraryGeorge EverestA series of letters : addressed to His Royal Highness the Duke of Sussex, as president of the Royal Society, remonstrating against the conduct of that learned body. → online text (page 12 of 13)