Longitude and the
Buenaventura River "JFC's recurring journal entries about his search for the fabled river...and his final conclusion that the river did not exist, seem almost like a deliberately introduced element to add to add continuity and suspense to the Report. It is hard to resist the suspicion that Jessie Benton Frémont's flair for the dramatic is somehow involved."
The [San]
Buenaventura River: For a complete history of the Buenaventure, read Cline, Gloria Griffin, Exploring the Great Basin, University of Oklahoma Press, Norman, 1963 (and University of Nevada Press reprint 1988). When the Bartelson-Bidwell Party headed west in 1841, they took carpentry tools so that they could build boats to sail down the Buenaventura. "An inteligent man with whom I boarded had a map which showed these rivers (one was the Buenaventura) to be large, and he advised me to take tools along to make canoes, so that...we could descend one of these rivers to the Pacific." John Bidwell On January 27, 1844, while scouting ahead with Tom Fitzpartick, Frémont encountered the West Fork of the Walker River flowing in a northerly direction through a canyon on the east side of the main chain of the Sierra Nevada Range. He commented in his Report; At the time, we supposed this to be the point into which they [the mountains at hand] were gathered between the two [Sacramento and San Joaquin] great rivers. Frémont had been looking for, and thought he had found, the Buenaventura River. He was quickly undecieved, but why, at that time, did he think this? A recent reading of Dava Sobel's best-selling Longitude got me thinking about lunars. In a check of the Astronomical Tables (pages 321-558) of Frémont's Report of The Exploring Expedition to the Rocky Mountains in the Year 1842, and to Oregon and North California in the Years 1843-'44, I found that he did attempt lunar observations on a few of occasions. These attempts, which were either complete failures or grossly in error, do, however, provide some answers to some previous puzzles.
 Frémont
carried the following instruments: a refracting telescope by
Frauenhofer; a reflecting circle by Gambey; two sextants by
Troughton; two pocket chronometers by Goffe and by
Brockbank; one syphon barometer by Bunten; one cistern
barometer by Freye & Shaw; six thermometers, a spyglass,
and a number of small compasses. The previous expedition to
the Rocky Mountains in 1842 had proved the superiority of
the pocket chronometer over the boxed and gimbaled
marine-type chronometer for rough traveling in extreme
conditions. The same was found by
Major W. H. Emory
1846:
"I saw then, and I now feel, the superiority of pocket over large chronometers for expeditions on foot or horseback." He had also purchased current editions of both American
and English Nautical Almanacs. These latter two contained
all the tables needed to reduce all his astronomical
observations to latitudes and longitudes. This equipment is
all listed in either the narrative of the Report, or
in the expense vouchers pertaining to the expedition.
He used several methods for obtaining longitude, but they
all but one required that he knew both his Local Time, which
could be determined by observation, and Greenwich Time,
which was carried along in his two chronometers. There were,
of course, no Standard Time Zones. Cities might set their
clocks to one time, but anywhere east or west of anywhere
else had a different Local Time. To monitor the rate of his
chronometers, he could calculate Greenwich time by using his
150X Frauenhofer telescope to make observations of
occultations (emersions and immersions) of the Jovian moons.
CLICK the image for more information. He would calculate Local Time by solar observation. It was not necessary that the chronometer displayed the exact time at Greenwich, or that it kept perfect time. It was only necessary that he knew how much ahead of or behind Greenwich Time the chronometer indicated, and how many seconds the chronometer gained or lost each day. These factors were used to adjust the reductions of the observations. It is analogous to factoring "index error" with an instrument like the sextant. But if his chronometers stopped, as they both did in January 1843, under the rigors of rough traveling over thousands of miles, and severity of climate, he could still attempt a longitude determination by a lunar observation using a sextant or the circle of horizons. But this was a difficult observation, involved may steps in the reduction, and there was much room for error. Longitude is time, and time is longitude. Sailors had been able to establish their north/south position with precision by the mid 16th century. [See DETERMINATION OF LATITUDE below]. But previous to the mid 18th century, one of the great scientific problems involving navigation and mapmaking was the lack of the means to find one's east/west position. Though from the time of Galileo, and his use of his telescope to time the orbits of the moons of Jupiter, longitude could be determined on land. For instance, Jupiter's brightest moons: Io, Europa, and Ganymede all have eccentricities at or near .000. For 250 years navigators used telescopes to spot easily observed configurations of these moons. Since these alignments occur at the same instant in time, no matter from where in the world the observation is made, a current Nautical Almanac told the navigator the Greenwich time. From that, with solar observations of local time, longitude could be calculated. Then, in the reign of Queen Anne, in 1714, the Longitude Act was passed, offering a reward of £20,000 to the one to discover the means of determining longitude at sea. The two competing methods for determining the longitude at sea became lunar observations and the chronometer. Newton, as President of The Royal Society, recognized that a a very accurate clock would enable these determinations to be made by comparing Local Time with Greenwich Time, but he doubted the possibility of building such a clock that would work on a ship at sea. Lunar observations (the measurement of an angle between the moon and the sun or planet or star) were possible; Newton himself had invented the quadrant of reflection (which later evolved into the sextant) to make such angular measurements, but did not build it . It was independently reinvented by two other astronomers (John Hadley in London and Thomas Godfrey in Philadelphia) in 1731. However, years of work would be needed by astronomers in the compiling of the necessary tables of Ephemerides -- the relative positions at Greenwich of the moon and each other useful celestial body needed to be calculated for any time for years ahead. By comparing the time that a particular angle between the moon and any of these other celestial objects occurred in Greenwich, and the Local Time of the observation, longitude could be calculated. But the calculation was tedious. But, in 1761, after forty years of development, John Harrison's H4 chronometer was undergoing successful trials at sea, and Longitude determinations were at hand. The ability to carry Greenwich time stored in the chronometer, and comparing that with Local Time, proved to make the determination of longitude much faster and simpler, and because of this, the results proved much more accurate. On the Second Expedition, as stated above, Frémont carried two "pocket chronometers"--by Goffe and by Brockbank--a survivor of the 1st Expedition. "Pocket chronometers," are not the same as the large cased and gimbaled "marine chronometer." Pocket chronometers are large, accurate pocket watches. They are chain-driven with a fusee, have maintaining power, with spring detant or roller lever escapement, and are regulated in at least two positions (stem up/face up, which is a compromise). Frémont had learned from his First Expedition experience, that the large cased chronometers could not withstand the rigors of the trail. After only 12 days on the trail, his large chronometer, by French, was already having problems. After working with it for a number of days, he finally left it behind at Fort Laramie and continued on with the Brockbank pocket chronometer. Cf. a similar finding by Major W. H. Emory, two years later: October 14, 1946: So, on the Second Expedition, he gave up something in potential accuracy in the interest of portability and reliability. But by making periodical celestial observations with his telescope, he would be able to monitor the rate-of-going of his watches. Below is an example of a determination made both by meridian transit of the sun and, later, by the observation of the time of the emersion of the first satellite of jupiter.
Watches require lubrication; the high summer temperatures encountered on the outward leg of of the expedition would thin the oil and allow it to migrate, and subfreezing winter temperatures in the high mountains would cause the lubricant to become highly viscous. In January, in the high deserts of the western Great Basin, his chronometers had stopped! Even if he could get one running, which he did, would it keep time--in any event, he had lost Greenwich Time. In describing the condition of the expedition party, Frémont recorded the following:
By the latitude, he knew that he is not much north of San Francisco Bay and Sutter's Fort. But, because he had been unable to make a determination of longitude, he was not sure just how far west he would have to go to reach it. He then spent days scouting about on the Truckee, Carson, and Walker rivers, searching for what could be an easier way out--the fabled Buenaventura River. The Buenaventura was shown on maps to flow from the Rocky Mountains, through the Sierra Nevada, to the Pacific. Men like Joseph Walker, Jedediah Smith, Zenas Leonard, Joseph Chiles, Ewing Young, and even Kit Carson, who had been on one side or both sides of the Sierra Nevada, knew that the Buenaventura was not there. The Calafornia [sic] mountain extends from the Columbia to the Colorado River..,but in no place is there a water course through the mountain. Zenas Leonard (with Walker), June 7, 1833 But, if they had missed it; if there was any chance at all, Frémont had the opportunity to either debunk the story, or, even better, become "The discoverer of the Buenaventura River" [the American equivalent of discovering The Northwest Passage] and save the expedition in the process. On November 18, 1843, at the beginning of the return leg of the journey, Frémont states: From this lake...[actually Klamath Marsh] It is important to remember that, though trappers had been on both sides of the Sierra, and the Bartelson-Bidwell party (including Joseph Chiles) crossed the Sierra at very near this point in 1841, there were NO reliable maps of the West based on surveys. These people had all traveled without even a compass. The only positions that Fremont had to work with were those of Pacific Coastal Surveys--some of the determinations going back to early Spanish times. In fact, Frémont discovered an error of nearly ten miles in the recently completed Coastal Survey by Captain Wilkes, and determined that the the position laid down for the port of Monterey in 1791 by Malaspina was, in contrast to the latter, nearly correct. But the rivers he finds all flow the wrong way. Until, near today's town of Bridgeport; January 26. The river is fifty or eighty feet wide, with a lively current, of very clear water. It forked a little above our camp, one of its branches coming directly from the south. At its head appeared to be a handsome pass; and from the neighboring heights we could see, beyond, a comparatively low and open country, which was supposed [he supposed] to form the valley of the Buenaventura. The next thing that Frémont needed to do was to find out how far west he had to travel to reach the Sacramento Valley. He had to discover his longitude. We must turn to the pages 321-558 of The Report--the tables of Astronomical Observations. These tables show the date and time of the observations, reductions, and determinations of time, latitude, and longitude. The last position (N42° 51' 26" / W121° 20' 42") that Frémont had been able to determine was on December 13th, 1843, some miles east of Klamath Marsh. Frémont had great confidence in this determination; it was based on the observation of an emersion of Jupiter's first satellite, and an observation made a few days earlier, on the 8th, of a lunar occultation of n Geminorium (in the constellation Gemini). A check of these determinations on modern maps show that his confidence was indeed warranted. He had since been traveling in a generally southerly direction, making "daily surveys with the compass." By December 16th, at latitude N42° 57' 22", he was having enough problems with the chronometer that he failed in two attempts at a determination of longitude. Between December 16th and January 24th, although his determinations of latitudes by double altitudes (he needed to use an artificial horizon on land) of polaris, were excellent, he failed in 21 attempts at determining longitude taking double altitudes of leonis, cygni, or procyon. For the latitudes determined by polaris, time is not so critical. A good determination can be made if you have the time within a few minutes. Time within fractions of seconds is necessary for accurate longitude: At Frémont's latitude a clock error of just one second would result in a longitude error of nearly a quarter of a mile!. By January 16th, the expedition had traveled four degrees south of his last determination of longitude. Then, between his encampment at Pyramid Lake on January 16 (N38° 51' 13") and his arrival at Bridgeport (N38° 18' 01") on January 25th, Frémont wandered around between the Truckee, Carson, and various forks of the Walker Rivers. He was making the last ditch effort for The Buenaventura. Why there? Frémont says, " I was not unmindful of of the disasters which Smith, and other travelers, had met with in this country, and therefore was equally vigilant in guarding against treachery and violence." He was therefore aware of Jedadiah Smith's journeys. And he was also aware that Joseph Walker had not traveled through the country as far north as Pyramid Lake. Carson had been up the western slope of the Sierra as far as the 38th parallel in 1829 with Ewing Young. If there was a river passage through the Sierra flowing to the Pacific, he would have seen it. If it existed, it had to be north of where Carson had been--it had to be right where he was. They scouted up streams looking for beaver sign, which Carson told him would indicate a river connected to the Pacific. No beaver sign was found, and all the rivers flowed the wrong way. Having determined himself that he cannot go through the mountains, he set out to go over them. But how far was he from the Sacramento Valley? Was there another reason? Years later, in an article in the April 1891 edition of Century Magazine, Frémont said, "A river, the 'Buenaventura,' indicated upon a map furnished me by the Hudson's Bay Company [on the recent visit] as breaking through the mountains, was found not to exist......." Peter Ogden, and the Hudson's Bay Company had to know better; was The Pathfinder being led around the bush?
1--In the early morning hours, using his Circle of
Horizons, he measured the distance for the first limb of the
Moon to Venus--he took a lunar. Lunar observations
often involve angles greater than the 120° (+10) on the
scale of the sextant. The circle of horizons can measure an
angle of 300°. Comparing his angle with his Lunar
Ephemerides, he determined that the time at Greenwich was
14hrs 57min 48.8sec. Comparing that with the Local Time he
had recorded at noon, he determined that his longitude was
121° 49' 52"--within a half a degree of longitude of
his last determination on a tributary to the Williamson
River (see page 479 of 1845 Senate edition below). If his
noon determination was correct, and if his chronometer was
keeping time between noon and evening, and if he had made no
errors in a complicated reduction, then his determination
should have been correct. If it was correct, he was very
near the confluence of the Sacramento and San Joaquin
Rivers. I don't believe that he was, even then, very
confident of his results, but it was enough to look into. So
the next day he and Fitzpatrick would have a look. 2--He attempted a longitude determination by the altitude of the sun. 3--He made a latitude determination by meridian transit at noon. Neither of these two yielded results, but they did allow him to determine his Local Time at noon as 0hr 28min 52sec -- this by his chronometer, as a check of the equation of time for the day, would have told him the the sun would be 12min 19sec late by the clock. He would need to adjust by the difference. 4--He measured the altitude of polaris and correctly found his latitude as 38° 18' 01". 5--He made a failed attempt at longitude by the altitude of procyon. It was doubtful that the chronometer was keeping time, after all. The result from the 26th is shown on the map at right and below.  It is easy to see why, as the result of the determination of longitude on January, 26th, as shown on the maps above, he recorded the following thought on the next day: January 27. Leaving the camp to follow slowly, with directions to Carson to encamp at the place agreed on, Mr. Fitzpatrick and myself continued the reconnoissance. Arriving at the head of the stream, we began to enter the pass--passing occasionally through open groves of large pine-trees, on the warm side of the defile, where the snow had melted away, occasionally exposing a large Indian trail. Continuing along a narrow meadow, we reached, in a few miles, the gate of the pass, where there was a narrow strip of prairie about 50 yards wide, between walls of granite rock. On either side rose the mountains, forming on the left a rugged mass, or nucleus, wholly covered with deep snow, presenting a glittering and icy surface. At the time, we supposed this to be the point into which they [the mountains at hand] were gathered between the two [Sacramento and San Joaquin] great rivers. If, indeed, he had been near the confluence of the Sacramento and San Joaquin Rivers, as his determination of longitude West 120° 50' indicated, then the route he had been following for the previous few days must have been taking him through the Sierra Nevada--the Buenaventura! This might have seemed reasonable to him at that time. His determined elevation near Bridgeport was 6,310' (nearly correct). He had now climbed to near 7,500'. He had already determined the elevation of the South Pass of the Rocky Mountains to be 7,490, and, as his later determination at Carson Pass shows, he had no expectation of finding the elevation of the Sierra Nevada in any way equal to the legendary loftiness of the Rockies. Ahead to February 20, 1844: Thus, at the extremity of the continent, and near the coast, the phenomenon was seen of a range of mountains still higher than the great Rocky Mountains themselves. In the next few hours he knew that this was not true. In the few days he refined his determination of time and longitude, but opportunities for lunars and observations of Jupiter don't come along all the time: January 28. To-night we did not succeed in getting the Howitzer into camp. This was the most laborious day we had yet passed through; the steep ascents and deep snow exhausting both men and animals. Our single chronometer had stopped during the day, and its error in time occasioned the loss of an eclipse of a satellite this evening. It had not preserved the rate with which we started from the Dalles, and this will account for the absence of longitudes along this interval of our journey. The determination of longitude made on January 26 was not included in the list of positions 0n pages 321-327 of The Report, nor did it make it into the narrative entry for the date other than the conjectures on the Buenaventura. It exists only on page 479. It is an example of the difficulties of lunars. The very brightness of the moon, when the bright limb is used, relative to the object brought to it, is part of the problem. But he did manage to make other observations to improve his time as he went along. The longitude determinations shown on the map above for the 14th and 24th of February are fairly good.
More important, in the ten days between these two observations and determinations, it is obvious that the chronometer was again maintaining its rate. Even though made under very difficult conditions, these determinations are as good as an average determination made at sea in that day. Remember, At Frémont's latitude a clock error of just one second would result in a longitude error of nearly a quarter of a mile! So, they are off enough that the 1845 Frémont/Preuss Map misconnected the headwaters with the lower reaches of many of the Sierra rivers.
The longitudes of 1845 Frémont/Preuss map were ultimately based on 18 stations: 4 by lunar occultation's of fixed stars and 14 by eclipses of the moons of Jupiter. Frémont corrected these longitudes the following year on the Third Expedition, and the rivers were were corrected on the 1848 Frémont/Preuss Map.
But the issue of the Buenaventura River was finally put to rest. Frémont recorded his own conclusion in the Report: January 29, 1844. Well, not quite. As the report of the Second Expedition was being prepared, and the maps were being engraved, Frémont, then 31 years old, was awarded a double brevet in rank from President Tyler--from Second Lieutenant to Captain. A few weeks later, after the change of administrations in Washington, Frémont, accompanied by his father in law Senator Thomas Hart Benton, arrived at the office of President Polk. During the interview, Frémont explained that the map of the West in the Library of Congress was in error in regard to the rivers of the Great Basin (Frémont coinage)--particularly in regard to the existence of three rivers, one of which was the Buenaventura River. Of the interview, Frémont wrote: The president seemed for the moment sceptical.....Like the Secretary [of the Navy] he found me "young," and said something of the "impulsiveness of young men," and was not at all satisfied in his own mind that those three rivers were not running there as laid down. The Great Basin: the concept and name
coined by Frémont. "This concept rightly belongs to Frémont,
though like many important ideas it had antecedents
that could lay partial claim to its achievement.
Galitan's map, the other one which rivals
Frémont's, was of value chiefly because it
incorporated Jedediah Smith's routes on it. But
this map, [like Bonneville's] was extremely
vague and amateurish. Based on thousands of careful
observations of latitude and longitude,
Frémont's map of 1845 [was] a
landmark in geographical knowledge." "Thus it came about that it was the fur trappers
and traderswho were destined to explore the
interior-drainage basin, although it was the leader
of another scientific expedition, John Charles
Frémont, who was to achieve a geological
understanding of the Great Basin. In 1844,
Frémont came to the reluctant conclusion
that the vast interior between the Wasatch and the
Sierra Nevada was indeed a great basin, and so
named it. The dream of a western road to Cathay,
set in motion by Columbus, finally came to rest in
this area when the last spike of a transcontinental
railroad was driven at Promontory Point, Utah, in
1869." Thanks to Jerry Dwyer,
of Castro
Valley,
for input and corrections as to
Frémont's location east of Klamath Marsh in the North
West. Jerry will soon have two articles on this part of the
expedition's travels posted on the Klamath County Genweb
site. When they are posted, there will be a link from this
site. Watch for them. A brief bibliography: Bowditch, Nathaniel, Ll. D., The New American Practical Navigator, E. and G. W. Blunt, New York, 23rd Edition, 1853. Bray, Martha Coleman, Joseph Nicollet and His Map, The American Philosophical Society, Philadelphia, 1980. Frémont, John Charles, Geographical Memoir Upon Upper California, [Ho. of Reps. 30th Congress, Misc. No. 5, 1849 Tippin & Streeper, Washington. Frémont, John Charles, Memoirs of My Life, Belford, Clark & Company, Chicago, 1887. Frémont, Brevet Captain J. C., Report of The Exploring Expedition to the Rocky Mountains in the Year 1842, and to Oregon and North California in the Years 1843-'44, Printed by order of the Senate of the United States, Gales and Seaton, Washington. 1845. Greely, Gen. A. W., American Weather, Dodd, Mead & Company, New York, 1888. Jackson, Donald, and Spence, Mary Lee, The Expeditions of John Charles Frémont, Vol. 1, University of Illinoise Press, 1970. Knight, Edward H., Knight, American Mechanical Dictionary, J. B. Ford and Company, New York, 1874-1879. Negretti & Zambra, A Treatise on Meteorological Instruments, London, 1864. Nicollet, J. N., Essay on Meteorological Observations, Printed by order of the War Department, Washington, 1839. Sobel, Dava, Longitude: The Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time, Walker Publishing Co., Inc., 1995. Williamson, R. S., On the Use of the Barometer on Surveys and Reconnaissances; part I, Meteorology in its Connection with Hypsometry; part II, Barometric Hypsometry; D. Van Nostrand, New York, 1868.
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January
27, 1844. At the time, we supposed this to be the
point into which they [the mountains at
hand] were gathered between the two great
rivers.
January
18. I rode out with Mr. Fitzpatrick and Carson to
reconnoitre the country...Examining into the condition of
the animals when I returned into the camp, I found their
feet so cut up by the rocks, and so many of them lame,
that it was evidently impossible that they could cross
the country to the Rocky Mountains...I therefore
determined to abandon my eastern course, and to cross the
Sierra Nevada into the valley of the Sacramento, wherever
a practicable pass could be found. My decision was heard
with joy by the people, and diffused new life throughout
the camp. Latitude by observation, 39° 24' 16".
Near
today's town of Bridgeport, the expedition took a day of
rest at a site now inundated by Bridgeport Reservoir. This
allowed for some reconnoitering and some celestial
observations. Frémont made six different
observations:
