broken. In order to be ready for work as soon as it should be repaired,
Lieut. Com. Green proceeded to Bahia with the ship and established a
station there, Lieut. Com. Davis with his party remaining in Rio. After
waiting a month, and there still seeming to be no prospect of the
repair of the cable, the expedition finally sailed for home, arriving
at Norfolk, Va., after a pleasant and uneventful voyage of forty-five
days. Repairs to the cable were not completed until several months
afterward. In May of the next year, the party was again sent out, to
complete the measurement on the Brazilian Coast, and also to measure
from Greenwich to Lisbon, the French Bureau of Longitudes having failed
to carry out its promise to measure from Paris. There being no ship
available for the purpose the traveling was done by mail steamer. Upon
arrival in England, an interview was had with the Astronomer Royal, who
readily agreed to assist in the work. Lieut. Com. Green accordingly
established his observatory at the landing place of the cable at
Porthcurnow in Cornwall, and Lieut. Com. Davis proceeded to Lisbon and
occupied the station used there the year before. Owing to the foggy and
rainy weather prevalent in England at that season, it was found
impossible to make any astronomical observations at the Porthcurnow
observatory. The work was therefore done in this way:--Observations
were made at Greenwich and at Lisbon, and Porthcurnow and Carcavellos
were used as transmitting stations. The chronometer at Porthcurnow was
compared automatically with the clock at Greenwich, and by cable with
the chronometer at Carcavellos. The latter was compared automatically
with that at Lisbon, before and after the cable exchange. At this time
there were made at Carcavellos, some experiments with a view to making
the receipt of the time signals over the cable automatic, thus doing
away with the personal equation of the receiver. The instrument in use
for the regular business of the cable was what is known as the siphon
recorder, also the invention of Sir Wm. Thompson. In this a small coil
of fine wire is suspended by a fibre of silk, between the poles of a
powerful permanent magnet. The currents from the cable pass through
this coil and the action is to deflect it to the right or left, just as
the mirror is deflected in the instrument already described. Attached
to this coil is a siphon made of a capillary glass tube. One end of the
siphon dips into a reservoir of aniline ink, and the other hangs
immediately over the centre of a fillet of paper, which is unwound by
clock-work. If the siphon touched the paper, the feeble currents sent
through the cable would be powerless to move it, on account of the
friction, and in order to produce a mark some means must be found of
forcing the ink through the capillary tube. This is accomplished by
electrifying the ink positively and the paper negatively, by means of a
small inductive machine, driven by an electric motor. The effort of the
two electricities to unite, forces the ink through the tube and it
appears on the paper as a succession of small dots. When the paper is
in motion and the coil at rest, a straight line is formed along the
middle of the fillet by these dots, but as soon as a current is sent
through the coil the siphon moves to the right or left making an offset
to this line. These offsets on one side or the other are used as the
dots and dashes of the Morse alphabet. A time signal sent over the
cable while this instrument was in circuit, appeared as a single offset
on the paper, and it was only necessary to graduate the paper into
seconds spaces by the local chronometer, in order to have the automatic
record required. The ordinary chronometer circuit could not be put
through the coil directly, as it would then charge the cable and
interfere with the signals, and besides, the current, unless by the
introduction of a high resistance it was reduced in strength, would
infallibly give such a violent motion to the coil as to break the
siphon, if it did no other damage. The result was obtained in this way;
an ordinary telegraph relay was put in the chronometer circuit and the
armature of course moved with the beats. To this armature was fastened
one end of a fine thread. The other end was attached to a slender piece
of elastic brass which was fixed at one end to the framework supporting
the paper, in such a way that the other end touched the metallic vessel
holding the ink, except when the thread was drawn tight enough to pull
it away. This the armature of the relay did while the circuit through
the chronometer was complete, but as soon as it was broken at the
beginning of a second, the tension of the thread was relaxed and the
brass sprung back against the ink well, allowing the positive and
negative electricities to unite independently of the siphon. The ink
then ceased to flow, until the spring was drawn away, thus leaving a
small blank space in the line of dots and forming a very good
chronographic record. This was liable to a small error due to the
length of time that elapsed between the release of the spring by the
armature and its impact on the ink well. Had there been time for more
extensive experiment this difficulty might have been overcome. Or if
the same method had been adopted at both stations, the result would
have been affected by only the difference between the times of movement
of the brass spring which would have been minute. Lack of time for
experiment, and the fact that the observers were averse to introducing
untested methods into a chain of measurements most of the links of
which were already completed, prevented any use being made of this
achievement. The measurement between Greenwich and Lisbon being
satisfactorily completed, Lieut. Com. Green by order of the Navy
Department returned to the United States, and the links between Rio and
Pernambuco and between the latter place and Para, were measured by
Lieut. Com. Davis and the writer, completing the work of the
expedition, after which the party returned to Washington.
The computation of this work, showed the somewhat surprising fact that
the heretofore accepted position in longitude of Lisbon, differed from
the true one by about two miles. The longitude of Rio Janeiro had
always been more or less in doubt, various determinations had differed
by as much as nine miles, but the position finally decided upon by the
best authorities agreed very closely with that obtained by telegraph.
The next expedition was sent out by the Bureau of Navigation to China,
Japan and the East Indies, Lieut. Com. Green being still in charge. The
officers composing the party sailed from San Francisco by mail steamer
in April, 1881, for Yokohama, where they joined the U. S. Steamer
Palos. From Hong Kong north to Vladivostok in Eastern Siberia the
cables were owned by a Danish company. From Hong Kong to the south and
west they were the property of English companies. Beginning at
Vladivostok observations were made at all stations on the Asiatic coast
except Penang, as far as Madras, India. It was intended to try and make
some use of the automatic method of receiving time signals, on this
work, but on arriving in Japan it was found that the recording
instrument used by the Danish company was entirely different from that
used by the English lines. It consisted of a series of electro-magnets
acting on a single armature, which carried a siphon made of silver. The
signals consisted of long and short movements, to one side of the
middle line, instead of equal deflections on both sides as in the
Thompson recorder. An attempt was made to convert this instrument into
a relay, by causing the siphon to make and break a circuit, but it was
not successful. The movements of the siphon were not regular enough,
and the contact was not firm. Consequently the mirror method of
exchanging signals was still adhered to.
The longitude of the position occupied in Vladivostok, had been
determined telegraphically from Pulkova, by the Russians, using the
land lines across Siberia. The English had also determined the position
at Madras, using the cables through the Mediterranean and Red Seas. The
work of the United States Expedition joined these two positions,
completing a chain of measurements extending over many thousand miles,
made by observers of different nationalities in various climates. It
was to be expected that considerable discrepancy would be found in the
final result, but taking the longitude of Vladivostok as brought from
Madras, and comparing it with that determined by the Russians, the
difference was only 0^{s}.39. Taking everything into consideration,
this result was gratifyingly close. Upon the conclusion of this series
of determinations, the connection of Lieut. Commander Green with the
work was severed, he receiving his promotion to the rank of Commander.
The next work was under the charge of Lieut. Com. Davis, and consisted
in the determination in 1883-84, of positions in Mexico, Central
America and the west coast of South America. Cables had just been
completed, extending from Galveston, Texas, to Vera Cruz, thence across
Mexico to the Pacific and down that coast to Lima, Peru, where
connection was made with another system extending to Valparaiso.
Galveston was a point determined by the Coast Survey, and the
measurement thence to Vera Cruz was the first one made. It was
completed in May '83, and in the Autumn of the same year the party
proceeded to the South American coast, and stations were established
and observations made at various points from Valparaiso to Panama, and
at one point, La Libertad, in Central America. It was at first the
intention to extend the series across the Isthmus of Tehuantepec and
connect with Vera Cruz, but lack of time prevented this, and as the
station at Panama determined nearly ten years before, afforded a
convenient starting point, the idea was abandoned. From Valparaiso, a
measurement was made with the coöperation of Dr. Gould to his
observatory at Cordova, using the line across the Andes, and exchanging
signals automatically. These measurements constituted the final links
in a long chain, extending from the prime meridian Greenwich across the
Atlantic to the United States, thence via the West Indies to Panama,
down the west coast of South America to Valparaiso, across the Andes to
Cordova and Buenos Ayres, up the east coast to Pernambuco, across the
Atlantic to Lisbon, and thence to Greenwich, altogether a distance of
eighteen to twenty thousand miles. The two longitudes of Cordova, as
brought from Greenwich by the two routes, differed from each other by
only 0^{s}.048, a result which speaks well for the accuracy of the
methods employed. When preparations were being made for this
expedition, it was determined to accomplish if possible something in
the way of getting rid of the personal equation in exchanging signals.
An idea which had been suggested by work done by Major Campbell, R. E.
in the measurement between Bombay and Aden, seemed to promise well. It
was to be used with the siphon or other form of recorder. The ordinary
double current cable key with two levers, was arranged with an
additional lever in such a manner that while in ordinary use in the
telegraph office, it could also be put in circuit with the chronometer
and chronograph in the observatory, and a signal sent through the cable
would have its time of sending registered on the chronograph.
Ordinarily in speaking over a cable line, connection is made in such a
way that the current sent does not pass through the recorder at the
sending station, as a violent movement of the siphon would result. By
means of a shunt, however, it is possible to control this movement
somewhat. Suppose now, that the connections at each station are made in
such a way, by means of this key and the shunt, that a signal sent from
one, is registered on both recorders and on the sender's chronograph.
The observers leaving their assistants to take care of the
chronographs, go to the respective telegraph offices, and all being
ready, the observer A taps his key. This sends an impulse through the
cable, which appears on A's recorder, as a violent jump or kick of the
siphon. On B's recorder it is registered as a deflection like the
ordinary dot or dash, at the same instant is recorded on A's
chronograph the time of sending. As soon as B sees the signal on his
recorder, he taps his key also registering the signals on both
recorders and on his chronograph. A, seeing B's signal again taps his
key, and so on, as long as desired. The result is that each observer
has a record on his siphon fillet of all signals sent and received,
while the times of those he sent are recorded on his chronograph. By
the use of the diagonal scale and the Rule of Three, he can without
difficulty find the times of the signals received. The siphon recorders
are well made, and the paper moves with great regularity. This system
was used in the measurement between Galveston and Vera Cruz with great
success. It was intended to employ the same method throughout the
measurement on the west coast of America, but on arriving at Lima, it
was found that the company owning the lines south of that point still
used the mirror galvanometer, and it was of course necessary to return
to the old method. The improved key was used however, which eliminated
the error in sending signals.
After this work was completed and the results published in 1885,
nothing was done in this line by the Bureau of Navigation for some
years. Upon the return of the writer in the spring of 1888, from a
cruise in the South Pacific, he found that the subject of sending an
expedition to complete the measurements in Mexico and Central America
was under consideration in the Bureau of Navigation and the
Hydrographic office. It was finally decided that the work should be
done, and the writer was placed in charge. The instruments were brought
out of their retirement, and by the aid of the Hydrographic Office a
very complete outfit was furnished, and in November of last year a
start was made from New York, the expedition proceeding by mail steamer
to Vera Cruz. Here the spot occupied by Lieut. Com. Davis in '83 was
found, his transit pier, which was still standing was repaired, and
instruments mounted. Lieut. Charles Laird, U. S. N., who had been
identified with the longitude work since the China expedition in 1881,
was left in charge of the observatory at Vera Cruz, and the writer
proceeded with his party to the small town of Coatzacoalcos, at the
mouth of the river of the same name. This point is about one hundred
and twenty miles southeast of Vera Cruz, and is the landing place of
the cable. A land line extends from this point to Salina Cruz on the
Pacific coast, a distance of about two hundred miles. In exchanging
time signals between Vera Cruz and Coatzacoalcos, the automatic method
was employed, the cable being short. The old wooden observatories were
used at these points, but as they were too heavy for transportation
across the Isthmus, tents made especially for astronomical purposes
were substituted for them in the observations made on the Pacific
coast. The journey across the Isthmus was slow, about two weeks being
employed in traveling two hundred miles, though as the route was
devious, the actual distance was nearer three hundred. Some of the
instruments were heavy, and after being taken in canoes a hundred miles
up the Coatzacoalcos river, against a rapid current, they were loaded
on a train of pack mules, and carried the rest of the way by land.
While the first party was crossing the Isthmus, the other was on its
way from Vera Cruz, and being ready at about the same time, a
successful measurement was made between Coatzacoalcos and Salina Cruz,
exchanging signals automatically. The Coatzacoalcos party then crossed
to Salina Cruz, while the other proceeded to La Libertad in Salvador,
where the station established in the Spring of '84, was again occupied.
The measurement between these places being completed, the Libertad
party went on to San Juan del Sur, in Nicaragua, near the terminus of
the proposed interoceanic canal. In the measurement between this point
and Salina Cruz, as well as in the one preceding, the exchange was
effected by mirror signals. This completed the season's work, and the
two parties made the best of their way home via Panama, arriving in
Washington in April and May respectively. The computation of the
observations is not yet complete though well advanced; it was the
intention to publish preliminary results this Fall, but owing to lack
of time that can not be done.
Another piece of work is laid out for the same party for the coming
winter, which is the measurement from Santiago de Cuba, through Hayti
and San Domingo to La Guayra in Venezuela, over the cables of a French
company, which have just been completed. This work will consume about
six months, and the expedition which is to start almost immediately
will probably return in April or May next. The determination of the
longitude of La Guayra will give a point from which many other
measurements may be made along the north coast of South America,
furnishing material for extensive corrections of the charts of that
region.
* * * * *
Having presented an outline of the work done so far, as well as that
proposed for the near future, I will now mention some of the trials and
tribulations, as well as the pleasures experienced in carrying out the
object desired in an expedition of this kind. The greatest politeness
and kindness have always been experienced from the officials and
employees of the various telegraph companies over whose lines work has
been carried on. The government officials of the foreign countries
visited, have also invariably shown the utmost politeness, but
sometimes this politeness has been visibly tinged with suspicion. The
measurements in Peru and Chili were made amid the closing scenes of the
war between the countries. Upon the arrival of the expedition in Lima,
an interview was had with the Chilian Commander-in-Chief who had
possession of the city, and permission was requested and readily
granted to occupy a station in Arica. Upon arriving at the latter place
some days after, the Chilian governor in charge was found to have
instructions to facilitate the work, and readily granted permission to
establish the observatory in a convenient locality, but flatly refused
to allow a wire to be extended to the telegraph office, and also
refused to forward to his immediate superior, a request that it might
be allowed. He evidently supposed the party were emissaries of the
United States, sent to treat secretly with conquered Peru, but how he
expected this was to be done remains a secret. By a vigorous use of the
telegraph in communicating with the U. S. Ministers to both Chili and
Peru, his objections were silenced, and the wire was put up. The
observatory at Arica was erected on the side of a hill to the windward
of the town, because it afforded a clear view, and was less dirty than
other eligible sites. It also was a safe position in case of a possible
earthquake or tidal wave, by which Arica had already been twice visited
with disastrous effect. In digging for a foundation for the transit
pier, several mummies of the ancient Peruvians were unearthed at a
depth of a foot. They had evidently belonged to the poorer class of
people, as their wrappings were composed of coarse mats, instead of the
fine cloth with which the wealthier people were usually interred. One
was the body of a female with long hair, which had been turned to a
reddish yellow color by the alkali in the soil. The whole coast of Peru
is barren and desolate, except in the river valleys, it being seldom
visited by rain, while it is nearly always overhung with heavy clouds
and fog banks, which render astronomical work exceedingly difficult.
Even when partially clear in the day time, it generally becomes cloudy
at night. Many times the observer would be at his place before sunset
ready to seize the first suitable star revealed by the darkness, only
to be baffled by thick banks of cloud which would cover the entire sky
in from five to ten minutes.
In northern Peru, with a latitude of about five degrees south, is the
town of Paita. It is an assemblage of mud-colored houses, at the foot
of high, mud colored bluffs. On top of these bluffs is a perfectly
barren table land extending inland and up and down the coast for many
miles. Before visiting it the observers were informed that its one good
point was the perfect astronomical weather which always prevailed.
Clouds were unknown, and such a thing as rain had never been heard of.
The extreme dryness of the atmosphere was so favorable to health that
no one ever died, and when a consumptive invalid was imported by the
inhabitants in the hope of starting a cemetery, he blasted their
expectations by recovering. Judge then of their feeling, when upon
arriving at this delightful place, they were met with the information
that while it was true that the sky was, in general, perfectly clear
both by night and day, yet about once in seven years, rain could be
expected, and that the year then present was the rainy one. And sure
enough it did rain. The usually dusty streets became rivers and
quagmires, the rocky valleys in the vicinity were transformed into
roaring torrents, and the table land usually an arid desert became a
swamp with a rank growth of vegetation. However by using every
opportunity and snatching stars between clouds and showers the work was
finally completed.
Upon arriving in Panama shortly after this experience, the party was
met with the pleasant intelligence that yellow fever was prevalent, and
that the foreigners were dying like sheep. Nearly every day of the
party's stay, some one died of sufficient importance to have the church
bells tolled for his funeral, while of the ordinary people little
notice was taken. Every morning, the writer remembers passing a
carpenter's shop where nothing was made but coffins, and the supply was
evidently not equal to the demand, for finally the proprietor began to
import them, apparently by the ship load. The weather however was
delightful, and the nights were the most perfect, astronomically
speaking, that could be desired.
The observers who went from Japan to Vladivostok were obliged to wait
several weeks at Nagasaki, before an opportunity offered for proceeding
to their destination, and when they finally arrived, the getting away
again was a problem. Communication with the outside world by water was
only open during the summer months, and even then it was more
accidental than otherwise. The party established the observatory
however, and settled down to work, letting the future take care of
itself. In the early part of the work, rather an amusing incident
occurred. As the community was full of all sorts and conditions of men,
Koreans, Chinamen and Russian exiles, the last not political but
criminal offenders; it was thought wise to have a sentry stationed at
the observatory to guard against any possible harm to the instruments.
So the Governor of the town was asked to furnish a soldier for that
purpose, which request was readily granted, and one night the sentry
was posted with orders to let no one touch the observatory. These
orders he construed literally, and when the observers appeared to
commence their night's work, he kept them off at the point of the
bayonet. His only language being Russian with which the observers were
not familiar, it was impossible to explain the true state of affairs,
and it was only after hunting up an interpreter and communicating with
his commanding officer that an entry was finally effected. A good deal
of bad weather was experienced at this place, but at the end of six
weeks enough observations had been made for the required purpose, and
the party was fortunate enough to secure passage to Nagasaki, in a
small steamer that had brought a load of coal out from Germany.
In the expedition to the Asiatic coast one of the most interesting
experiences was the trip to Manila in the Philippine Islands. This is
quite a large town when intact, but a great portion of it is usually in
the condition of being shaken down by an earthquake or blown over by a
typhoon. The inhabitants are full of energy, however, and find time
between downfalls to build up again. The cable from Hong Kong lands at
a point about one hundred and twenty miles from Manila, and the writer
was directed to proceed thither, with a chronometer and chronograph for
the purpose of transmitting time signals. The first part of the journey
was made in a small coasting steamer uncommonly dirty, and occupied
about thirty-six hours. At the end of that time the village of Sual in
the Gulf of Lingayen was reached. This was distant from the cable
station about thirty miles, and the remainder of the journey was made
in a native boat, with mat sails, and bamboo outriggers, part of the
time through channels between numerous small islands and for some
distance in the open sea. The progress was slow, but it was a pleasant
way of traveling, except for the sleeping accommodations which were
primitive; consisting of a palm leaf mat thrown over a platform made of
split bamboo, in which all the knots had been carefully preserved.
About three days, including stoppages, were consumed in this thirty
mile voyage, and the traveler finally reached his destination to be
received with the greatest hospitality by the staff at the telegraph
station, and just in time to allay the fears of the observers at Hong
Kong and Manila who had begun to think him lost. About three weeks were
spent here, and as the work only occupied a short time at night, the
days were pleasantly passed in exploring the surrounding country,
making friends with the natives, shooting and photographing the
scenery. The return to Manila was by the same route and occupied nearly
the same length of time.
The measurement from Singapore to Madras was over one of the longest
lines of cable ever used for this purpose, the distance being about
1600 nautical miles. The Atlantic cables used by Dr. Gould in 1866 were
a little more than 1,850 miles in length. There was an intermediate
station at Penang about 400 miles from Singapore, where all the work of
the line was repeated. For the longitude measurement however the cables
were connected through to form an unbroken line. The mirror was the
only instrument that could be used and even with this the signals were
feeble and much affected by earth currents.