1825

Philosophy of Systematic Scientific Observations and Elimination of Error

"Absolute mathematical accuracy exists only in the mind of man. All practical applications are mere approximations, more or less successful. And when all has been done that science and art can unite in practice, the supposition of some defects in the instruments will always be prudent. It becomes therefore the duty of an observer to combine and invent, upon theoretical principals, methods of systematical observations, by which the influence of any error of his instruments may be neutralised, either by direct means, or more generally by compensation.”

In the Principal Documents (1825) by Ferdinand Hassler, Founder of the United States Survey of the Coast, Published by New Series, Philadelphia. p.390.

1839

On Dredging the Depths of the Ocean

"Song of the Dredge”, presented by Edward Forbes to the British Association at its annual meeting in 1839.

Hurrah for the dredge, with its iron edge, And its mystical triangle. And its hided net with meshes set Odd fishes to entangle! The ship may move thro’ the waves above, ‘Mid scenes exciting wonder, But braver sights the dredge delights As it roves the waters under.

Chorus:
Then a-dredging we will go wise boys
A-dredging we will go!
A-dredging we will go, a-dredging we will go,
A-dredging we will go, wise boys,
A-dredging we will go!

Down in the deep, where the merman sleep,
Our gallant dredge is sinking;
Each finny shape in a precious scrape
Will find itself in a twinkling!
They may twirl and twist, and writhe as they wist
And break themselves into sections,
But up they all, at the dredge’s call,
Must come to fill collections.

Chorus:
The creatures strange the sea that range,
Though mighty in their stations,
To the dredge must yield the briny field
Of their loves and depredations.
The crab so bold, like a knight of old,
In scaly armour plated,
And the slimy snail, with a shell on his tail,
And the star-fish ----- radiated!

As quoted by Sir William Herdman in: Founders of Oceanography and Their Work. 1923. London, Edward Arnold & Co. P. 17-18.

1854

Benjamin Peirce and the Ultimate Limits of Accuracy

As powerful as the method of “least squares” is, under certain conditions its most probable estimation of truth may in fact be quite misleading. Superintendent Bache’s good friend, Harvard mathematician Benjamin Peirce, pointed this out in a treatise appended to the Coast Survey report for 1854 under the unlikely name “Report upon the Determination of Longitude by Moon Culminations.” Although meant as an argument in favor of his thesis that longitude determinations by moon culminations of the Pleiades had the potential to be the most accurate possible, this document is memorable for its lucid discussion of the various types of observational errors as well as for its understanding of the ultimate attainable limits of accuracy. As such, Peirce’s major points are applicable to most types of scientific observation and the paper could be considered a landmark in American scientific thought.

Peirce began with the supposition that with only one observation of a physical quantity that observation must be adopted as the true value of the constant. However, “A second observation gives a second determination, which is always found to differ from the first. The difference of the observations is an indication of the accuracy of each, while the mean of the two determinations is a new determination which may be regarded as more accurate than either.”

As more and more observations are acquired, "The comparison of the mean with the individual determinations has shown, in all cases in which such comparison has been instituted, that the errors of lunar observation [or most species of scientific observation are subject to law, and are not distributed in an arbitrary and capricious manner. They are the symmetrical and concentrated groupings of a skillful marksman aiming at a target, and not the random scatterings of a blind man, nor even the designed irregularities of the stars in the firmament. This law of human error is the more remarkable, and worthy of philosophic examination, that it is precisely that which is required to render the arithmetical mean of observations the most probable approach to the exact result. It has been made the foundation of the method of least squares, and its introduction into astronomy by the illustrious Gauss is the last great era of this science. ”

Peirce continued: “If the law of error embodied in the method of least squares were the sole law to which human error is subject, it would happen that by a sufficient accumulation of observations any imagined degree of accuracy would be attainable in the determination of a constant; and the evanescent influence of minute increments of error would have the effect of exalting man’s power of exact observation to an unlimited extent. I believe that the careful examination of observations reveals another law of error, which is involved in the popular statement that ‘man cannot measure what he cannot see.’ The small errors which are beyond the limits of human perception, are not distributed according to the mode recognised by the method of least squares, but either with the uniformity which is the ordinary characteristic of matters of chance, or more frequently in some arbitrary form dependent upon individual peculiarities -- such, for instance, as an habitual inclination to the use of certain numbers. On this account it is in vain to attempt the comparison of the distribution of errors with the law of least squares to too great a degree of minuteness; and on this account there is in every species of observation an ultimate limit of accuracy beyond which no mass of accumulated observations can ever penetrate."

"A wise observer, when he perceives that he is approaching this limit, will apply his powers to improving the methods, rather than to increasing the number of observations. This principle will thus serve to stimulate, and not to paralyze effort; and its vivifying influence will prevent science from stagnating into mere mechanical drudgery....”

In Annual Report of the Superintendent of the Coast Survey for 1854 (1855). Appendix 36 “Report upon the Determination of Longitude by Moon Culminations.” Printed by A.O.P. Nicholson, Public Printer. pp. 108-120.

Benjamin Pierce, third Superintendent of the Coast Survey, was a Harvard mathematician and astronomer. (Courtesy of NOAA Photo Library.) Download larger version (jpg, 78 KB).

1858-1

Deep-Sea Sounding Difficulties

"The explorations of the Gulf Stream by officers of our navy, in connection with the survey of the coast, first gave rise to systematic efforts to determine sections of the bottom of the sea along lines of great depth; afterwards the extensive system of deep-sea soundings executed under the direction of the Navy Department, through the exertions of Lieut. Maury, furnished most useful experience and results, and more recently the soundings along the line of the proposed Atlantic telegraph, first by Lieut. Comg. Berryman, United States navy, and again by Lieut. Comg. Joseph Dayman, R.N., have shown that to reach the bottom of the sea is not beyond the power of human effort."

"Notwithstanding so much has been done to overcome the practical difficulties which formerly embarrassed and discouraged any attempts to sound at great depths, it is undeniable that much uncertainty exists in the determinations that have been made even when the depth is not greater than 2,000 fathoms; while below 2,000 or 2,500 fathoms, the errors and uncertainties amount to failures; and a limit has been reached beyond which it seems difficult to pass."

"When the subject is viewed as a mechanical problem it seems hardly possible, however, that insurmountable obstacles can exist to its practical solution. The facility with which an observer can place himself over any point, the distance of which below the plane on which he rests it is his object to determine, and from which he is separated by a medium freely and almost equally penetrable at all depths, the laws of which are well known, would seem to offer greater hopes of our being able ultimately, to determine the depressions of the bottom of the ocean by a greater number of observations, and with greater accuracy, than the elevations of the continents."

"The solution of the question requires that the difficulties which have been found to exist in the present methods of sounding, should be clearly determined and overcome, and when these methods fail, that they should be improved, if possible, or new ones substituted..." In "Investigation of the laws of motion governing the descent of the weight and line in deep-sea soundings"

(1859) by Prof. W.P. Trowbridge, Assistant in the Coast Survey. Published in Report of the Superintendent of the Coast Survey Showing the Progress of the Survey During the Year 1858. Appendix No. 37, published by William A. Harris, Washington. pp. 228-239.

1858-2

Need for Improved Modes of Sounding

"The idea of a ‘plateau’ existing between Newfoundland and Ireland is not warranted, it seems to me, by any observations that have yet been made. The range of errors may be as great as 500 fathoms, which would admit of the existence of a submarine mountain on this line half as high as Mount Washington. A true section of the Atlantic can only be determined by improved modes of sounding, since, from the preceding discussion, we may be warranted in the conclusion that it is practically impossible to determine the greatest depths of the ocean by the methods now in use.”

In "Investigation of the laws of motion governing the descent of the weight and line in deep-sea soundings" (1858) by Prof. W.P. Trowbridge, Assistant in the Coast Survey. Published in Report of the Superintendent of the Coast Survey Showing the Progress of the Survey During the Year 1858 Appendix No. 37, published by William A. Harris, Washington. pp. 228-239. Written at the Coast Survey office, Washington, D.C., May 31, 1858.

1880-1

American Pride

"Without specifying the great results obtained from this continuous research, I may be pardoned in referring with some gratification to the fact that in the small steamer ‘Blake,’ of only three hundred and fifty tons burthen, N.M., under the energetic and skillful commands of Lieutenant-Commander Sigsbee and Commander Bartlett, with a full complement of forty-five including officers and crew, more rapid work was done than had been accomplished with the old methods and appliances by the Challenger, a vessel of over 2,000 tons burthen, with a complement of twenty-nine naval and civil officers and a correspondingly large crew.”

Carlile Patterson in introduction to “Deep Sea Sounding and Dredging: A Description and Discussion of the Methods and Appliances Used on Board the Coast and Geodetic Survey Steamer, Blake,” by Charles D. Sigsbee, 1880. Published by Government Printing Office, Washington. p. 5.

A steam winch with steel wire was first used for deepsea dredging on the Coast Survey Steamer Blake. Source: Deep Sea Sounding and Dredging (1880) by C. Sigsbee. (Courtesy of NOAA Photo Library.) Download larger version (jpg, 105 KB).

1880-2

Early Advances on the Blake

"Moreover it is becoming the Britons, whether scientific or unscientific, who boast at all fitting occasions of their aptitude to rule the waves, should know something of the population of their saline empire, especially of those parts of it immediately in contact with their terrestrial domain, and the coasts of the Continent to which our United Kingdom appertains.”

In The Natural History of the European Seas (1859) by E. Forbes, posthumously. Published by John Van Voorst, London. p. 3.

1880-3

Care in Navigating the Blake

"Our navigation-record was comprehensive, and adapted to future revision or verification.”

In Deep Sea Sounding and Dredging: A Description and Discussion of the Methods and Appliances Used on Board the Coast and Geodetic Survey Steamer, Blake (1880) by C. D. Sigsbee. Published by Government Printing Office, Washington. p. 12.

1880-4

Working on the Blake

"The longest continuous run that we ever made on sounding-lines occupied eleven days, although that length of time was nearly equaled on several occasions. These long runs were sometimes executed under such trying circumstances of wind, weather, sea, and current as to impose much mental strain on the officers and to call forth all the endurance of the crew. At sea, everything had to give way to the work in hand. If the vessel did not look pretty, we concluded that we could not help it, and complacently looked forward to a higher standard on our arrival in port. It was generally understood and appreciated by all on board that mistakes through carelessness ought not to be tolerated, and that strictness should rule always in matters immediately connected with the special purpose of our party. In port, on the contrary, the fullest liberty of action, not at variance with good order and the interests of the work, was allowed.”

In Deep Sea Sounding and Dredging: A Description and Discussion of the Methods and Appliances Used on Board the Coast and Geodetic Survey Steamer, Blake (1880) by C. D. Sigsbee. Published by Government Printing Office, Washington. p. 12.

A steam winch with steel wire was first used for deepsea dredging on the Coast Survey Steamer Blake. Source: Deep Sea Sounding and Dredging (1880) by C. Sigsbee. (Courtesy of NOAA Photo Library.) Click image for larger view.

1888-1

Alexander Agassiz on the First Use of Steel Cable by an Oceanographic Ship

"My familiarity with the successful use of very long steel ropes for mining purposes naturally suggested their adaptation to the new purpose of deep sea work.”

In Three Cruises of the Blake (1888) by A. Agassiz. Published by Houghton, Mifflin, and Company, Boston. p.28.

All dredging cruises previous to the first cruise of the Blake had used hemp rope for dredging.

1888-2

Alexander Agassiz on Ocean Temperatures

"A great objection to the use of Miller-Casella [a maximum - minimum recording thermometer] for obtaining deep-sea temperatures is found in the fact that they will register only the lowest temperatures observed.....When, however, we seek to ascertain the temperatures of the Gulf Stream, or to work in the Arctic regions, where the coldest water may be nearest the surface, we are unable, of course, to determine the position of the coldest or warmest intermediate layers of water. The only perfect method of taking serial temperatures is one which records them continuously on deck during the descent of the thermometer. Such an apparatus has been devised by Sir William Siemens. In the Bakerian Lecture for 1871, he showed that the principle of the variation with the temperature of the electrical resistance of a conductor might be applied to the construction of a thermometer, which would be in use in cases where a mercurial thermometer was not available. The instrument he described has since been largely used as a pyrometer for determining the temperatures of hot blasts and smelting furnaces; and it has been found that its indications agree very closely with those of an air-thermometer. He devised a similar instrument for measuring temperatures where a much greater degree of accuracy is required, as in the case of deep sea observations; and during the autumn of 1881, this deep-sea electric thermometer was subjected to a series of tests on board the Blake by Commander Bartlett.”

In Three Cruises of the Blake (1888) by A. Agassiz. Volume I. Published by Houghton, Mifflin, and Company, Boston, pp. 16-17.

1888-3

The Working Atmosphere on the Blake

"It is pleasant to notice that the harmony between the naturalists and officers of the “Blake” was not for an instant disturbed during the time they were working in common. Everything in the way of naval routine was sacrificed for the time to the objects of the cruise, and the appearance of the deck and bow of the Blake was often more that of a mud-scow than of a vessel in the service of the United States.”

In Three Cruises of the Blake (1888) by A. Agassiz, Volume I, p. 50.

1921

The Role of Echo Sounding in Exploring the Sea I: A Supplementary Device

Depth determinations by means of reflected sound from the bottom are reported to be feasible; andthough it may never supplant the standard method of sounding, there is a possibility of it becoming a valuable supplementary device.”

In “Mapping the Pacific - Survey of Shoreline and Coastal Waters” by Commander J.T. Watkins, U. S. Coast and Geodetic Survey. Published in The Proceedings of the First Pan-Pacific Scientific Conference, August 2-20, 1920 (1921). Special Publication Number 7, Part 1, 1921 by the Bernice P. Bishop Museum.

One of the earliest diagrams of echo-sounding in a published work. Source: In Die Meteor-Fahrt Forschungen, The Meteor Expedition (1928) by F. Speiss.
Citation: In Die Meteor-Fahrt Forschungen, The Meteor Expedition (1928) by F. Speiss. Fahrt Forschungen und Erlebnisse der Deutschen Atlantischen Expedition, 1925-1927. D. Reimer, Berlin. (Courtesy of NOAA Photo Library.) Download larger version (jpg, 43 KB).

1926

The Contribution of Steam Power to Oceanography

"Before steam came in to enable the mariner to keep his ship over one spot it was quite impossible to take an accurate sounding over 100 fathoms. The Challenger had moderate steam power, but was not fitted with the excellent sounding engines and wire line of the present day. She used Italian hemp, which, as it carried air down in its interstices, went slower and slower and marked the great depths badly....”

"The weights on the hemp line were so heavy that they were slipped each time and left at the bottom, and it is possible that in future geological ages they will be recorded as meteorites that have come from other worlds or from cosmic space.”

In Nature Notes for Ocean Voyagers (1926) by A. Carpenter and D. W. Barker, 2nd edition. Published by Charles Griffin, London. p. 4.

1932-1

Sailing by the Wind

"Walking aft a few feet we stand at the steering gear of the ship. There is no cozy; wheel-house on the bridge for the quartermaster of a sailing ship! He must stand at the very stern, with an unobstructed view of the sails. When sailing “by the wind” his eye is glued to the weather-side of the uppermost sail; he keeps it drawing a trace of wind, but never lets it fill.”

In The Last Cruise of the Carnegie (1932) by J. H. Paul. Published by The Williams and Wilkins Co., Baltimore. p. 36.

1932-2

Storms and Too Much Equipment

".... On the next day we had the worst storm of the passage. We were forced to heave to and ride it out. Several of the bronze fittings in the rigging were carried away. However, damage was not so serious that emergency repairs could not be made. The vessel was having a bad time of it. Time and again seas swept the quarter-deck, something which rarely occurred on previous cruises. This was probably due to the load carried aft. The new winch, generators, batteries, and so on, used for our oceanographic work, weighed several tons.”

In The Last Cruise of the Carnegie (1932) by J. H. Paul. Published by The Williams and Wilkins Co., Baltimore. p. 77-78.

1932-3

Hypothesis vs. Reality

"There was one great surprise in the results. All of those who discussed the project in its early stages questioned whether radio acoustic work would be successful on the northwest Pacific Coast of the United States on account of heavy surf noise interfering with the signals and the difficulties of installing shore stations and cables, while it was taken for granted that no difficulty would be encountered on the Atlantic Coast. The exact opposite proved the case and it is only recently in the course of the Georges Bank work that use under Atlantic Coast conditions has proven practicable.”

In “Beginnings of Acoustic Work in the Coast and Geodetic Survey” by N.H. Heck, in “Association of Field Engineers U. S. Coast & Geodetic Survey Bulletin,” June 1932, No. 5, p. 48.

1939-1

Progress in Mapping the Seafloor

"Surveys of water areas, usually called hydrographic surveys, have one large handicap not encountered in land surveying -- namely, the sea, lake, or river bed is usually invisible to the surveyor. This is, perhaps, the main reason why hydrographic surveys are so fascinating. In addition to the interesting problems connected with routine tasks - seamanship, handling of observations, and computations - there is always the anticipation of finding some new and unsuspected feature of the sea bottom. In conducting echo sounding surveys there is the additional attraction of being able to observe the continuous variations in ocean bed topography as the surveying vessel steams along on the sea surface sometimes a thousand fathoms or more above the land being mapped. “To a casual observer on a modern surveying ship that is obtaining echo soundings, and is being controlled in position by radio-acoustic ranging, the whole process might appear remarkably simple. But to the engineers, both hydrographic and electrical, and the crews who have contributed to the development and perfection of some of these methods and applied them to the surveyors’ needs, it still seems almost incredible that a system has been devised that is so practical as it is, a procedure that permits the rapid accumulation of thousands of accurate soundings and accurate positions of soundings in darkness, fog, or out of sight of visual control. We look back on this development sometimes and wonder that it has been made to work so well and realize that many of the most serious difficulties have not been those of physics and engineering, but those involving skill and experience in seamanship, and the knowledge and ability that come only after long experience in dealing with the ever uncertain quantities -- weather and waves. To the men of the crews, therefore, of the vessels of the Survey must be given a large share of the credit for success in the “sea going” use of methods and instruments usually not found outside a physics laboratory.”

In "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley” by (1939) A.C. Veatch and P. A. Smith. Published by Geological Society of America (Special Papers Number 7). pp. 53-54.

1939-2

Methods, Errors, and Accuracy

"... It is of the utmost importance in any study of these data to have a thorough knowledge of the methods used, what probable errors to expect, and the changing relative accuracy as certain improvements increase the accuracy of the results from year to year; that is to say, one must acquire at least a speaking acquaintance with many technical details that are second nature to an experienced hydrographer.”

In "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley” by (1939) A.C. Veatch and P. A. Smith. Published by Geological Society of America (Special Papers Number 7). p. 55.

1939-3

The Potential of the Self-Renewing ResourcesThe Role of Echo Sounding in Exploring the Sea of the Sea

"Echo sounding has, indeed, opened an almost unlimited field in geology and related earth sciences. Through it we shall be able to achieve extensive and intensive exploration of the vast submerged areas of our planet that hold so much of geologic history hidden under thousands of fathoms of sea.”

In "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley” by (1939) A.C. Veatch and P. A. Smith. Published by Geological Society of America (Special Papers Number 7). p. 61.

1939-4

New Systems - New Needs

"And thus we advance; what is adequate today may be inadequate tomorrow, and, as better methods and equipment are perfected and demands for new facts and knowledge are made, resurveys are periodically necessary. Surveys of tomorrow doubtless will make those of today seem quite inadequate.”

In "Atlantic Submarine Valleys of the United States and the Congo Submarine Valley” by (1939) A.C. Veatch and P. A. Smith. Published by Geological Society of America (Special Papers Number 7). p. 69.

1955

The Pioneer Survey II

"The Survey had developed a very effective radio navigation system which could be installed along the coast to provide precise (within a hundred feet) position information out to distances of a few hundred miles. Existence of this system is basically what made the entire resulting operation, both topographic and magnetic mapping, possible.” This quote refers to the Pioneer survey which was funded by the Navy for determining offshore bathymetry on the west coast. The Scripps Institution of Oceanography funded using the first shipboard towed magnetometer from the Pioneer. This convergence of interests led to the discovery of magnetic striping on the sea floor, a key element in formulating the theory of Plate Tectonics.

In “Some Origins and Perspectives in Deep-ocean Instrumentation Development” (1980) by F. N. Spiess. Published in Oceanography the Past (1980) edited by M. Sears and D. Merriman. Published by Springer-Verlag, New York. p. 230.

1969-1

The Need for Accurate Navigation

"One of the problems that has plagued oceanography from its beginning is the difficulty of establishing position above, on, and beneath the ocean surface. The requirements for position accuracy differ from place to place and from problem to problem. In the case of geophysical measurements on the continental shelf, a precision of a few feet may be required, whereas for certain biological measurements in the open ocean, an uncertainty of several miles is acceptable. There are also studies, such as the measurement of surface currents, where high relative precision, where the order of tens of yards, is required, but where accurate knowledge of the absolute position is unnecessary. Certain geophysical studies, such as gravity measurements, also require precise navigation in order to determine the Eotvos correction....”

In An Ocean Quest - The International Decade of Ocean Exploration (1969) National Academy of Sciences. p. 92.

1969-2

A Global Satellite Navigation System

".... An ideal [navigation] system would include the following characteristics: global coverage, common geodetic datum, constant availability, unambiguity, absolute accuracy of at least 200 m, capability of random access, self-monitoring, relative simplicity at the sensor, capability of providing different ranges of accuracy, and availability to infinite numbers of users. “....It would be a synchronous satellite -based system. With ground-tracking stations located on a common geodetic datum, the spatial positioning of the satellite could be well determined and monitored. The system should be global ....”

In An Ocean Quest - The International Decade of Ocean Exploration (1969) National Academy of Sciences. p. 93.

1980

Wisdom in Using What Works

"... when the opportunity arises one should take whatever proven techniques he has and go to sea. Waiting for the ultimate system to be available can lead to indefinite delays and no new science – the better system can always be used on the next expedition.”

In “Some Origins and Perspectives in Deep-ocean Instrumentation Development” (1980) by F. N. Spiess. Published in Oceanography the Past (1980) edited by M. Sears and D. Merriman. Published by Springer-Verlag, New York. p. 230.