One hardly knows where, in the history of science, to look for an
important movement that had its effective start in so pure and simple
an accident as that which led to the building of the great Washington
telescope, and went on to the discovery of the satellites of Mars.
Very different might have been a chapter of astronomical history,
but for the accident of Mr. Cyrus Field, of Atlantic cable fame,
having a small dinner party at the Arlington Hotel, Washington, in the
winter of 1870. Among the guests were Senators Hamlin and Casserly,
Mr. J. E. Hilgard of the Coast Survey, and a young son of Mr. Field,
who had spent the day in seeing the sights of Washington. Being
called upon for a recital of his experiences, the youth described his
visit to the observatory, and expressed his surprise at finding no
large telescope. The only instrument they could show him was much
smaller and more antiquated than that of Mr. Rutherfurd in New York.
The guests listened to this statement with incredulity, and applied to
Mr. Hilgard to know whether the visitor was not mistaken, through a
failure to find the great telescope of the observatory. Mr. Hilgard
replied that the statement was quite correct, the observatory having
been equipped at a time when the construction of great refracting
telescopes had not been commenced, and even their possibility was
doubted.
"This ought not to be," said one of the senators. "Why is it so?"
Mr. Hilgard mentioned the reluctance of Congress to appropriate
money for a telescope.
"It must be done," replied the senator. "You have the case properly
represented to Congress, and we will see that an appropriation goes
through the Senate at least."
It chanced that this suggestion had an official basis which was not
known to the guests. Although Mr. Alvan Clark had already risen into
prominence as a maker of telescopes, his genius in this direction
had not been recognized outside of a limited scientific circle.
The civil war had commenced just as he had completed the largest
refracting telescope ever made, and the excitement of the contest,
as well as the absorbing character of the questions growing out
of the reconstruction of the Union, did not leave our public men
much time to think about the making of telescopes. Mr. Clark had,
however, been engaged by Captain Gilliss only a year or two after the
latter had taken charge of the observatory, to come to Washington,
inspect our instruments, and regrind their glasses. The result
of his work was so striking to the observers using the instruments
before and after his work on them, that no doubt of his ability could
be felt. Accordingly, in preparing items for the annual reports of
the observatory for the years 1868 and 1869, I submitted one to the
superintendent setting forth the great deficiency of the observatory
in respect to the power of its telescope, and the ability of Mr. Clark
to make good that deficiency. These were embodied in the reports.
It was recommended that authority be given to order a telescope of
the largest size from Mr. Clark.
It happened, however, that Secretary Welles had announced in his
annual reports as his policy that he would recommend no estimates for
the enlargement and improvement of public works in his department,
but would leave all matters of this kind to be acted on by Congress
as the latter might deem best. As the telescope was thrown out of
the regular estimates by this rule, this subject had failed to be
considered by Congress.
Now, however, the fact of the recommendation appearing in the annual
report, furnished a basis of action. Mr. Hilgard did not lose a
day in setting the ball in motion.
He called upon me immediately, and I told him of the recommendations
in the last two reports of the superintendent of the observatory.
Together we went to see Admiral Sands, who of course took the warmest
interest in the movement, and earnestly promoted it on the official
side. Mr. Hilgard telegraphed immediately to some leading men of
science, who authorized their signatures to a petition. In this paper
attention was called to the wants of the observatory, as set forth
by the superintendent, and to the eminent ability of the celebrated
firm of the Clarks to supply them. The petition was printed and put
into the hands of Senator Hamlin for presentation to the Senate only
three or four days after the dinner party. The appropriation measure
was formally considered by the Committee on Naval Affairs and that on
Appropriations, and was adopted in the Senate as an amendment to the
naval appropriation bill without opposition. The question then was
to get the amendment concurred in by the House of Representatives.
The session was near its close, and there was no time to do much work.
Several members of the House Committee on Appropriations were
consulted, and the general feeling seemed to be favorable to
the amendment. Great, therefore, was our surprise to find the
committee recommending that the amendment be not concurred in.
To prevent a possible misapprehension, I may remark that the present
system of non-concurring in all amendments to an appropriation bill,
in order to bring the whole subject into conference, had not then
been introduced, so that this action showed a real opposition to the
movement. One of the most curious features of the case is that the
leader in the opposition was said to be Mr. Washburn, the chairman
of the committee, who, not many years later, founded the Washburn
Observatory of the University of Wisconsin. There is, I believe,
no doubt that his munificence in this direction arose from what he
learned about astronomy and telescopes in the present case.
It happened, most fortunately, that the joint committee of conference
included Drake of the Senate and Niblack of the House, both earnestly
in favor of the measure. The committee recommended concurrence,
and the clause authorizing the construction became a law. The price
was limited to $50,000, and a sum of $10,000 was appropriated for
the first payment.
No sooner were the Clarks consulted than difficulties were found
which, for a time, threatened to complicate matters, and perhaps delay
the construction. In the first place, our currency was then still
on a paper basis. Gold was at a premium of some ten or fifteen per
cent., and the Clarks were unwilling to take the contract on any but
a gold basis. This, of course, the Government could not do. But the
difficulty was obviated through the action of a second one, which
equally threatened delay. Mr. L. J. McCormick, of reaping-machine
fame, had conceived the idea of getting the largest telescope that
could be made. He had commenced negotiations with the firm of Alvan
Clark & Sons before we had moved, and entered into a contract while
the appropriation was still pending in Congress. If the making of
one great telescope was a tedious job, requiring many years for its
completion, how could two be made?
I was charged with the duty of negotiating the government contract
with the Clarks. I found that the fact of Mr. McCormick's
contract being on a gold basis made them willing to accept one
from the Government on a currency basis; still they considered that
Mr. McCormick had the right of way in the matter of construction,
and refused to give precedence to our instrument. On mature
consideration, however, the firm reached the conclusion that two
instruments could be made almost simultaneously, and Mr. McCormick
very generously waived any right he might have had to precedence in
the matter.
The question how large an instrument they would undertake was, of
course, one of the first to arise. Progress in the size of telescopes
had to be made step by step, because it could never be foreseen how
soon the limit might be met; and if an attempt were made to exceed it,
the result would be not only failure for the instrument, but loss
of labor and money by the constructors. The largest refracting
telescope which the Clarks had yet constructed was one for the
University of Mississippi, which, on the outbreak of the civil war,
had come into the possession of the Astronomical Society of Chicago.
This would have been the last step, beyond which the firm would not
have been willing to go to any great extent, had it not happened that,
at this very time, a great telescope had been mounted in England.
This was made by Thomas Cooke & Sons of York, for Mr. R. S. Newall of
Gateshead on Tyne, England. The Clarks could not, of course, allow
themselves to be surpassed or even equaled by a foreign constructor;
yet they were averse to going much beyond the Cooke telescope in size.
Twenty-six inches aperture was the largest they would undertake.
I contended as strongly as I could for a larger telescope than
Mr. McCormick's, but they would agree to nothing of the sort,--the
supposed right of that gentleman to an instrument of equal size being
guarded as completely as if he had been a party to the negotiations.
So the contract was duly made for a telescope of twenty-six inches
clear aperture.
At that time Cooke and Clark were the only two men who had ever
succeeded in making refracting telescopes of the largest size. But in
order to exercise their skill, an art equally rare and difficult
had to be perfected, that of the glassmaker. Ordinary glass,
even ordinary optical glass, would not answer the purpose at all.
The two disks, one of crown glass and the other of flint, must be not
only of perfect transparency, but absolutely homogeneous through and
through, to avoid inequality of refraction, and thus cause all rays
passing through them to meet in the same focus. It was only about the
beginning of the century that flint disks of more than two or three
inches diameter could be made. Even after that, the art was supposed
to be a secret in the hands of a Swiss named Guinand, and his family.
Looking over the field, the Clarks concluded that the only firm that
could be relied on to furnish the glass was that of Chance & Co., of
Birmingham, England. So, as soon as the contracts were completed,
one of the Clark firm visited England and arranged with Chance &
Co. to supply the glass for the two telescopes. The firm failed in
a number of trials, but by repeated efforts finally reached success
at the end of a year. The glasses were received in December,
1871, and tested in the following month. A year and a half more
was required to get the object glasses into perfect shape; then,
in the spring or summer of 1873, I visited Cambridge for the purpose
of testing the glasses. They were mounted in the yard of the Clark
establishment in a temporary tube, so arranged that the glass could
be directed to any part of the heavens.
I have had few duties which interested me more than this. The
astronomer, in pursuing his work, is not often filled with those
emotions which the layman feels when he hears of the wonderful power
of the telescope. Not to say anything so harsh as that "familiarity
breeds contempt," we must admit that when an operation of any sort
becomes a matter of daily business, the sentiments associated with
it necessarily become dulled. Now, however, I was filled with
the consciousness that I was looking at the stars through the most
powerful telescope that had ever been pointed at the heavens, and
wondered what mysteries might be unfolded. The night was of the
finest, and I remember, sweeping at random, I ran upon what seemed
to be a little cluster of stars, so small and faint that it could
scarcely have been seen in a smaller instrument, yet so distant
that the individual stars eluded even the power of this instrument.
What cluster it might have been it was impossible to determine,
because the telescope had not the circles and other appliances
necessary for fixing the exact location of an object. I could
not help the vain longing which one must sometimes feel under such
circumstances, to know what beings might live on planets belonging
to what, from an earthly point of view, seemed to be a little colony
on the border of creation itself.
In his report dated October 9, 1873, Admiral Sands reported
the telescope as "nearly completed." The volume of Washington
observations showed that the first serious observations made with it,
those on the satellites of Neptune, were commenced on November 10
of the same year. Thus, scarcely more than a month elapsed from
the time that the telescope was reported still incomplete in the
shop of its makers until it was in regular nightly use.
Associated with the early history of the instrument is a chapter
of astronomical history which may not only instruct and amuse the
public, but relieve the embarrassment of some astronomer of a future
generation who, reading the published records, will wonder what became
of an important discovery. If the faith of the public in the absolute
certainty of all astronomical investigation is thereby impaired,
what I have to say will be in the interest of truth; and I have no
fear that our science will not stand the shock of the revelation.
Of our leading astronomical observers of the present day--of such
men as Burnham and Barnard--it may be safely said that when they
see a thing it is there. But this cannot always be said of every
eminent observer, and here is a most striking example of this fact.
When the telescope was approaching completion I wrote to the head of
one of the greatest European observatories, possessing one of the best
telescopes of the time, that the first thing I should attempt with
the telescope would be the discovery of the companion of Procyon.
This first magnitude star, which may be well seen in the winter
evenings above Orion, had been found to move in an exceedingly small
orbit, one too small to be detected except through the most refined
observations of modern precision. The same thing had been found in
the case of Sirius, and had been traced to the action of a minute
companion revolving around it, which was discovered by the Clarks
a dozen years before. There could be no doubt that the motion of
Procyon was due to the same cause, but no one had ever seen the
planet that produced it, though its direction from the star at any
time could be estimated.
Now, it happened that my European friend, as was very natural, had
frequently looked for this object without seeing it. Whether my
letter set him to looking again, or whether he did not receive
it until a later day, I do not know. What is certain is that,
in the course of the summer, he published the discovery of the
long-looked-for companion, supplemented by an excellent series of
observations upon it, made in March and April.
Of course I was a little disappointed that the honor of first
finding this object did not belong to our own telescope. Still I was
naturally very curious to see it. So, on the very first night on
which the telescope could be used, I sat up until midnight to take
a look at Procyon, not doubting that, with the greater power of our
telescope, it would be seen at the first glance. To my great concern,
nothing of the sort was visible. But the night was far from good,
the air being somewhat thick with moisture, which gave objects seen
through it a blurred appearance; so I had to await a better night and
more favorable conditions. Better nights came and passed, and still
not a trace of the object could be seen. Supposing that the light
of the bright star might be too dazzling, I cut it off with a piece
of green glass in the focus. Still no companion showed itself.
Could it be that our instrument, in a more favorable location,
would fail to show what had been seen with one so much smaller?
This question I could not answer, but wrote to my European friend
of my unavailing attempts.
He replied expressing his perplexity and surprise at the occurrence,
which was all the greater that the object had again been seen and
measured in April, 1874. A fine-looking series of observations
was published, similar to those of the preceding year. What made
the matter all the more certain was that there was a change in the
direction of the object which corresponded very closely to the motion
as it had been predicted by Auwers. The latter published a revision
of his work, based on the new observations.
A year later, the parties that had been observing the transit of Venus
returned home. The head of one of them, Professor C. H. F. Peters
of Clinton, stopped a day or two at Washington. It happened that
a letter from my European friend arrived at the same time. I found
that Peters was somewhat skeptical as to the reality of the object.
Sitting before the fire in my room at the observatory, I read to
him and some others extracts from the letter, which cited much
new evidence to show the reality of the discovery. Not only had
several of his own observers seen the object, but it had been seen
and measured on several different nights by a certain Professor Blank,
with a telescope only ten or twelve inches aperture.
"What," said Peters, "has Blank seen it?"
"Yes, so the letter says."
"Then it is n't there!"
And it really was not there. The maker of the discovery took it
all back, and explained how he had been deceived. He found that the
telescope through which the observations were made seemed to show a
little companion of the same sort alongside of every very bright star.
Everything was explained by this discovery. Even the seeming motion
of the imaginary star during the twelve months was accounted for by
the fact that in 1873 Procyon was much nearer the horizon when the
observations were made than it was the year following. [1]
There is a sequel to the history, which may cause its revision by some
astronomer not many years hence. When the great telescope was mounted
at the Lick Observatory, it is understood that Burnham and Barnard,
whose eyes are of the keenest, looked in vain for the companion
of Procyon. Yet, in 1895, it was found with the same instrument
by Schaeberle, and has since been observed with the great Yerkes
telescope, as well as by the observers at Mount Hamilton, so that the
reality of the discovery is beyond a doubt. The explanation of the
failure of Burnham and Barnard to see it is very simple: the object
moves in an eccentric orbit, so that it is nearer the planet at some
points of its orbit than at others. It was therefore lost in the
rays of the bright star during the years 1887-94. Is it possible
that it could have been far enough away to be visible in 1873-74?
I need scarcely add that this question must be answered in the
negative, yet it may be worthy of consideration, when the exact
orbit of the body is worked out twenty or thirty years hence.
In my work with the telescope I had a more definite end in view
than merely the possession of a great instrument. The work of
reconstructing the tables of the planets, which I had long before
mapped out as the greatest one in which I should engage, required
as exact a knowledge as could be obtained of the masses of all
the planets. In the case of Uranus and Neptune, the two outer
planets, this knowledge could best be obtained by observations on
their satellites. To the latter my attention was therefore directed.
In the case of Neptune, which has only one satellite yet revealed
to human vision, and that one so close to the planet that the
observations are necessarily affected by some uncertainty, it was
very desirable that a more distant one should be found if it existed.
I therefore during the summer and autumn of 1874 made most careful
search under the most favorable conditions. But no second satellite
was found. I was not surprised to learn that the observers with
the great Lick telescope were equally unsuccessful. My observations
with the instrument during two years were worked up and published,
and I turned the instrument over to Professor Hall in 1875.
The discovery of the satellites of Mars was made two years later,
in August, 1877. As no statement that I took any interest in the
discovery has ever been made in any official publication, I venture,
with the discoverer's permission, to mention the part that I took
in verifying it.
One morning Professor Hall confidentially showed me his first
observations of an object near Mars, and asked me what I thought
of them. I remarked, "Why, that looks very much like a satellite."
Yet he seemed very incredulous on the subject; so incredulous
that I feared he might make no further attempt to see the object.
I afterward learned, however, that this was entirely a misapprehension
on my part. He had been making a careful search for some time,
and had no intention of abandoning it until the matter was cleared
up one way or the other.
The possibility of the object being an asteroid suggested itself.
I volunteered to test this question by looking at the ephemerides
of all the small planets in the neighborhood of Mars. A very little
searching disproved the possibility of the object belonging to this
class. One such object was in the neighborhood, but its motion was
incompatible with the measures.
Then I remarked that, if the object were really a satellite, the
measures already made upon it, and the approximately known mass of
the planet, would enable the motion of the satellite to be determined
for a day or two. Thus I found that on that night the satellite would
be hidden in the early evening by the planet, but would emerge after
midnight. I therefore suggested to Professor Hall that, if it was
not seen in the early evening, he should wait until after midnight.
The result was in accordance with the prediction,--the satellite
was not visible in the early evening, but came out after midnight.
No further doubt was possible, and the discovery was published.
The labor of searching and observing was so exhausting that Professor
Hall let me compute the preliminary orbit of the satellites from
his early observations.
My calculations and suggestions lost an importance they might
otherwise have claimed, for the reason that several clear nights
followed. Had cloudy weather intervened, a knowledge of when to
look for the object might have greatly facilitated its recognition.
It is still an open question, perhaps, whether a great refracting
telescope will last unimpaired for an indefinite length of time.
I am not aware that the twin instruments of Harvard and Pulkowa,
mounted in 1843, have suffered from age, nor am I aware that any
of Alvan Clark's instruments are less perfect to-day than when they
left the hands of their makers. But not long after the discovery of
the satellites of Mars, doubts began to spread in some quarters as to
whether the great Washington telescope had not suffered deterioration.
These doubts were strengthened in the following way: When hundreds of
curious objects were being discovered in the heavens here and there,
observers with small instruments naturally sought to find them.
The result was several discoveries belonging to the same class
as that of the satellite of Procyon. They were found with very
insignificant instruments, but could not be seen in the large ones.
Professor Hall published a letter in a European journal, remarking
upon the curious fact that several objects were being discovered
with very small instruments, which were invisible in the Washington
telescope. This met the eye of Professor Wolf, a professor at the
Sorbonne in Paris, as well as astronomer at the Paris Observatory.
In a public lecture, which he delivered shortly afterward, he lamented
the fact that the deterioration of the Washington telescope had gone
so far as that, and quoted Professor Hall as his authority.
The success of the Washington telescope excited such interest the
world over as to give a new impetus to the construction of such
instruments. Its glass showed not the slightest drawbacks from its
great size. It had been feared that, after a certain limit, the
slight bending of the glass under its own weight would be injurious
to its performance. Nothing of the kind being seen, the Clarks were
quite ready to undertake much larger instruments. A 30-inch telescope
for the Pulkova Observatory in Russia, the 36-inch telescope of the
Lick Observatory in California, and, finally, the 40-inch of the
Yerkes Observatory in Chicago, were the outcome of the movement.
Of most interest to us in the present connection is the history
of the 30-inch telescope of the Pulkova Observatory, the object
glass of which was made by Alvan Clark & Sons. It was, I think,
sometime in 1878 that I received a letter from Otto Struve, [2]
director of the Pulkova Observatory, stating that he was arranging
with his government for a grant of money to build one of the largest
refracting telescopes. In answering him I called his attention to
the ability of Alvan Clark & Sons to make at least the object glass,
the most delicate and difficult part of the instrument. The result
was that, after fruitless negotiations with European artists, Struve
himself came to America in the summer of 1879 to see what the American
firm could do. He first went to Washington and carefully examined
the telescope there. Then he proceeded to Cambridge and visited the
workshop of the Clarks. He expressed some surprise at its modest
dimensions and fittings generally, but was so well pleased with what
he saw that he decided to award them the contract for making the
object glass. He was the guest of the Pickerings at the Cambridge
Observatory, and invited me thither from where I was summering on
the coast of Massachusetts to assist in negotiating the contract.
He requested that, for simplicity in conference, the preliminary terms
should be made with but a single member of the firm to talk with.
George B. Clark, the eldest member, was sent up to represent the firm.
I was asked to take part in the negotiations as a mutual friend of
both parties, and suggested the main conditions of the contract.
A summary of these will be found in the publication to which I have
already referred.
There was one provision the outcome of which was characteristic
of Alvan Clark & Sons. Struve, in testing some object glasses
which they had constructed and placed in their temporary tube,
found so great physical exertion necessary in pointing so rough
an instrument at any heavenly body with sufficient exactness,
that he could not form a satisfactory opinion of the object glass.
As he was to come over again when the glass was done, in order to
test it preliminary to acceptance, he was determined that no such
difficulty should arise. He therefore made a special provision
that $1000 extra, to be repaid by him, should be expended in making
a rough equatorial mounting in which he could test the instrument.
George Clark demurred to this, on the ground that such a mounting as
was necessary for this purpose could not possibly cost so much money.
But Struve persistently maintained that one to cost $1000 should
be made. The other party had to consent, but failed to carry out
this provision. The tube was, indeed, made large enough to test not
only Struve's glass but the larger one of the Lick Observatory, which,
though not yet commenced, was expected to be ready not long afterward.
Yet, notwithstanding this increase of size, I think the extra cost
turned out to be much less than $1000, and the mounting was so rough
that when Struve came over in 1883 to test the glass, he suffered
much physical inconvenience and met, if my memory serves me aright,
with a slight accident, in his efforts to use the rough instrument.
In points like this I do not believe that another such business firm
as that of the Clarks ever existed in this country or any other.
Here is an example. Shortly before the time of Struve's visit,
I had arranged with them for the construction of a refined and
complicated piece of apparatus to measure the velocity of light.
As this apparatus was quite new in nearly all its details, it was
impossible to estimate in advance what it might cost; so, of course,
they desired that payment for it should be arranged on actual cost
after the work was done. I assured them that the government would
not enter into a contract on such terms. There must be some maximum
or fixed price. This they fixed at $2500. I then arranged with
them that this should be taken as a maximum and that, if it was
found to cost less, they should accept actual cost. The contract
was arranged on this basis. There were several extras, including
two most delicate reflecting mirrors which would look flat to the
eye, but were surfaces of a sphere of perhaps four miles diameter.
The entire cost of the apparatus, as figured up by them after it was
done, with these additions, was less than $1500, or about forty per
cent. below the contract limit.
No set of men were ever so averse to advertising themselves.
If anybody, in any part of the world, wanted them to make a telescope,
he must write to them to know the price, etc. They could never be
induced to prepare anything in the form of a price catalogue of the
instruments they were prepared to furnish. The history of their
early efforts and the indifference of our scientific public to their
skill forms a mortifying chapter in our history of the middle of the
century. When Mr. Clark had finished his first telescope, a small
one of four inches aperture, which was, I have no reason to doubt,
the best that human art could make, he took it to the Cambridge
Observatory to be tested by one of the astronomers. The latter
called his attention to a little tail which the glass showed as
an appendage of a star, and which was, of course, non-existent.
It was attributed to a defect in the glass, which was therefore
considered a failure. Mr. Clark was quite sure that the tail was
not shown when he had previously used the glass, but he could not
account for it at the time. He afterwards traced it to the warm air
collecting in the upper part of the tube and producing an irregular
refraction of the light. When this cause was corrected the defect
disappeared. But he got no further encouragement at home to pursue
his work. The first recognition of his genius came from England,
the agent being Rev. W. R. Dawes, an enthusiastic observer of double
stars, who was greatly interested in having the best of telescopes.
Mr. Clark wrote him a letter describing a number of objects which
he had seen with telescopes of his own make. From this description
Mr. Dawes saw that the instruments must be of great excellence, and
the outcome of the matter was that he ordered one or more telescopes
from the American maker. Not until then were the abilities of the
latter recognized in his own country.
I have often speculated as to what the result might have been had
Mr. Clark been a more enterprising man. If, when he first found
himself able to make a large telescope, he had come to Washington,
got permission to mount his instrument in the grounds of the capitol,
showed it to members of Congress, and asked for legislation to
promote this new industry, and, when he got it, advertised himself
and his work in every way he could, would the firm which he founded
have been so little known after the death of its members, as it
now unhappily is? This is, perhaps, a rather academic question,
yet not an unprofitable one to consider.
In recent years the firm was engaged only to make object glasses
of telescopes, because the only mountings they could be induced to
make were too rude to satisfy astronomers. The palm in this branch
of the work went to the firm of Warner & Swasey, whose mounting of
the great Yerkes telescope of the University of Chicago is the last
word of art in this direction.
During the period when the reputation of the Cambridge family was
at its zenith, I was slow to believe that any other artist could
come up to their standard. My impression was strengthened by a
curious circumstance. During a visit to the Strasburg Observatory
in 1883 I was given permission to look through its great telescope,
which was made by a renowned German artist. I was surprised to find
the object glass affected by so serious a defect that it could not be
expected to do any work of the first class. One could only wonder
that European art was so backward. But, several years afterward,
the astronomers discovered that, in putting the glasses together after
being cleaned, somebody had placed one of them in the wrong position,
the surface which should have been turned toward the star being now
turned toward the observer. When the glass was simply turned over
so as to have the right face outward, the defect disappeared.
[1] In justice to Mr. Blank, I must say that there seems to have been
some misunderstanding as to his observations. What he had really
seen and observed was a star long well known, much more distant from
Procyon than the companion in question.
[2] Otto Struve was a brother of the very popular Russian minister to
Washington during the years 1882-92. He retired from the direction
of the Pulkowa Observatory about 1894. The official history of
his negotiations and other proceedings for the construction of the
telescope will be found in a work published in 1889 in honor of the
jubilee of the observatory.