The Origins and Early History of Earth Sciences at Yale

Excerpted from "Earth Sciences", by Karl K. Turekian and Barbara L. Narendra,in Science at Yale, edited by S. Altman, Yale University  2002

The purpose of this essay is to highlight several Yale faculty members over the past two hundred years who have been responsible for major contributions to the development of the earth sciences. Not all contributions have been identified, and there have been many over the years, but those included have clearly had a singular impact on the development of the earth sciences.

The Yale professors who are discussed in this essay are Benjamin Silliman, James Dwight Dana, Othniel C. Marsh, Joseph Barrell, Charles Schuchert, faculty members in earth science, and Elias Loomis, Josiah Willard Gibbs and Bertram Boltwood whose contributions to the earth sciences were significant although they were formally members of other science departments at Yale.

Benjamin Silliman (1779-1864): President Timothy Dwight had been interested in starting a program in the natural sciences and perhaps establishing a medical school at Yale. His interests led to identifying Benjamin Silliman, a lawyer by training and a dedicated alumnus of Yale College, as the person to begin the program of study of natural science at Yale. Silliman was appointed to this role in 1802. He began to explore the natural science scenery in Philadelphia and continued his education in Europe in the fields of chemistry, geology, and mineralogy.

In 1807 a meteorite fell with spectacular sound and light effects in Weston, Connecticut. This was the first documented fall of a meteorite in the New World--only 25 miles from New Haven. Silliman seized the opportunity to publish an analysis of the meteorite. The international attention his report received established a name for him and scientific fame for Yale. The meteorite was the first in the Yale collection of meteorites, now housed in the Peabody Museum (Narendra, 1978).

He founded the oldest continuing journal of natural science in the United States, the American Journal of Science, familiarly called "Silliman 's Journal", which continues to be published at Yale. Silliman was an excellent teacher and drew many students to Yale to study science and he was responsible for developing laboratory and field programs as well as starting the Yale cabinet of minerals. His inspired teaching gave rise to a group of scientists among whom was Amos Eaton, the educational innovator of the Rensselaer School (now the Rensselaer Polytechnic Institute). There is a direct connection between Amos Eaton and one of the most important geologists of the nineteenth century, James Dwight Dana.

James Dwight Dana (1813-1895): As a student at Utica (New York) High School, James Dwight Dana showed a strong interest and aptitude in science. He was encouraged by his science teacher who had attended Amos Eaton's school. When it came time for Dana to go to college it was almost inevitable that he would want to go to Yale to study with Benjamin Silliman. He arrived at Yale in 1830.

In August, 1838 he sailed with the United States Exploring Expedition under the command of Charles Wilkes. Two important things happened before Dana set sail that would affect his future life in science. First, he had a strong Christian enlightenment experience, and secondly, he had developed his system of mineralogy. The former affected his life in various ways including his resistance for many years to the theory of evolution, and the latter made sense of an unorganized field of mineral taxonomy. We still use Dana's "System of Mineralogy", now in its eighth edition (Gaines, et al., 1997) which is based on chemistry rather than morphology of crystals or associations.

Four years of exploration, mainly in the Pacific and the Pacific rim, provided Dana the background for much of his geologic thinking in the future. He came away from the experiences of the expedition with a large scale view of the development of geology. Much of geological exploration was regional at that time with careful mapping of strata or of ore deposits. It was Dana who viewed Earth as a whole. His unifying view was a contracting Earth which resulted in the mountains and broad troughs seen in such features as the Andes or the piles of sediments accumulated in eastern North America. His identification of the need for the broad depression of the Pacific sea floor to accommodate the upward growth of coral reefs to form the fringing reefs and atolls of the Pacific was a unique insight of Dana's and contributed to his grand view.

Dana did his work on the expedition as a natural scientist. He was a careful observer and collector. His work on the taxonomy of corals stands to this day.

While working on the reports of the Wilkes expedition, Dana looked for a job. At first there was nothing available at Yale but when Asa Gray at Harvard offered him a professorship there, private funds were forthcoming to keep Dana--already a famous scientist--in New Haven. A chair was established specifically for him, named for his father-in-law, Benjamin Silliman.

Dana was a correspondent with Charles Darwin since in many ways they had had similar experiences as shipboard scientists. Yet Dana did not accept Darwin's evolutionary ideas until the end of Dana's career. Perhaps it was his strong biblical training that deterred him for so long, but eventually he accepted evolution as the way in which a wondrous God did things.

Dana may also have been responsible for persuading a young Josiah Willard Gibbs from leaving Yale as we shall see later.

Othniel C. Marsh (1831-1899): When the time came for Othniel C. Marsh to go to college, his uncle, George Peabody, a man of means with a very strong sense of family and, ultimately civic responsibility, made sure he could attend Yale. This support of an uncle for his nephew would have consequences for the history of paleontology in the United States.

Marsh was committed to exploring the American west for fossils of extinct creatures. Indeed, many of the first exhumations and descriptions of the dinosaurs and early birds and mammals are due to him, his bands of Yale students, and his bone hunters digging in the hills of the western territories. His competitor was Edward D. Cope of Philadelphia and the Marsh-Cope fossil hunting "wars" are legendary.

Marsh became the first professor of paleontology in the United States. He played a pivotal role in establishing the fossil evidence for Darwin's evolutionary theory which was recognized as such by Thomas Huxley, the major proponent of Darwin's work. Huxley was impressed by Marsh's detailed fossil record of the evolution of the horse as well as his discovery of birds with teeth, presumed to be the link between dinosaurs and birds.

George Peabody, at his nephew's request, granted the money to build the initial Peabody Museum.

Elias Loomis (1811-1889): Although Elias Loomis was a professor of natural philosophy and not strictly a geologist, his contributions to atmospheric science and geomagnetism are important components in the development of the earth sciences (Newton, 1890). Indeed, Loomis's work was in the spirit of Dana's idea of the grand unity of the earth sciences.

Loomis encouraged the use of the growing national telegraph system in the 1850s, especially as used by the military, to record weather conditions around the United States. He was the first to use these synoptic data to map the air pressure differences across parts of the country. We are familiar with these maps today as showing isobars which define high pressure and low pressure areas. The pattern of isobars is our clue to the behavior of daily weather patterns. He was also an astronomer, bringing to Yale a field in which only amateur efforts existed in 18^th century Yale through the study of comets and meteors.

Loomis, in a sense, was the originator of experimental as well as observational meteorology. He noticed that when a tornado struck chickens were often stripped of their feathers. He conceived of a plan to determine the wind velocity in a tornado. He shot eight chickens from a cannon with different charges and therefore different muzzle velocities. The velocity that resulted in the plucking of the chicken's feathers therefore was a measure of the wind velocity in a tornado.

Terrestrial magnetism was an important part of Loomis's interests engendered in part because of his study of the aurora associated with solar activity.

Josiah Willard Gibbs (1839-1903): Gibbs also was not a geologist or paleontologist but rather he thought of himself as a mathematical physicist. He was the premier scientific intellect in the United States at the end of the nineteenth century. His importance to earth science is due to his formulation of the thermodynamics involved in heterogeneous equilibria. A rock clearly is an example of heterogeneous equilibrium. From Gibbs 's research came the concept of the phase rule. The number of degrees of freedom (things that must be determined independently) in a heterogeneous system is determined by the number of phases less the number of components plus temperature and pressure.

This idea developed in 1877 was first applied to rocks by the father of geochemistry, Victor M. Goldschmidt, in his thesis on the rocks of the Oslo (Norway) region. He applied Gibbs's phase rule to rocks and established the important idea of the "mineralogical" phase rule -- the number of minerals could not exceed the number of components.

The application of Gibbs's insights into thermodynamics revolutionized the entire treatment of the materials of the earth. Indeed one can argue that one of the most important contributions of Yale scientists to the study of the earth was Josiah Willard Gibbs's insights. When the newly founded elite Johns Hopkins University sought to acquire the best and the brightest minds they immediately sought out Gibbs. Luckily Gibbs did not leave Yale in part, probably, due to an important letter to him from the great James Dwight Dana dated April 26, 1880 in which Dana said:

"My dear Prof. Gibbs: I have only just now learned that there is danger of your leaving us. -- Your departure would be a very bad move for Yale. I have felt, of late, great anxiety for our University (using a name we are striving to deserve) because there seemed to be so little appreciation among our Graduates as to what we need, and so few benefactions in our favor; and now the idea of losing the leading man in one of our departments is really disheartening. I do not wonder that Johns Hopkins wants your name and services, or that you feel inclined to consider favorably their proposition, for nothing has been done toward endowing your professorship, and there are not here the means or signs of progress which tend to incite courage in Professors and multiply earnest students. But I hope nevertheless that you will stand by us, and that something will speedily be done by way of endowment to show you that your services are really valued. Johns Hopkins can get on vastly better without you than we can. We can not." (Wheeler, 1962).

Bertram Borden Boltwood (1870-1927): Although Boltwood was formally at first in the physics department and later in the chemistry department, the impact of his research on the development of geology was marked. Through his early interest in the rare earth elements he became entranced by the new field of radioactivity, particularly the establishment by Rutherford and Soddy in 1903 that the radioactive element really decayed away. It was probably the delivery of the Silliman Lectures by Rutherford in 1905 that propelled Boltwood into exploring this new field.

His biographer, Alois F. Kovarik, lists Boltwood's major accomplishments (Kovarik, 1929):

1. Discovery of a chemical element, ionium, the parent substance of radium.

2. Proving the genetic relation of uranium, ionium and radium.

3. Showing that certain elements have identical chemical properties -- the chemical inseparability of these elements -- a fact forming the starting point of many observations by many chemists and physicists which lead to isotopy.

4. Providing evidence that "lead" found in uranium minerals must be the final disintegration product of the uranium-radium series.

5. Devising a method for the calculation of the age of uranium minerals from their uranium and lead content.

6. Showing that actinium is in a genetic line of descent from uranium but not in the same line as radium.

We now know that ionium is really ²³⁰Th (with a half life of 75,000 years) and that the actinium he identified is in the ²³⁵U decay series chain.

Boltwood was the first person to use the U/Pb method of dating uranium-bearing minerals. He published these results in 1907. He gave ages from 535 million years for a uraninite from a pegmatite at Branchville, Connecticut to 2200 million years for a thorianite from Ceylon (now Sri Lanka). This unambiguously showed that the age of the earth had to be at least 2 billion years to the considerable relief of evolutionary biologists and most geologists.

Ionium (²³⁰Th), the parent of radium (actually ²²⁶Ra, since there are several isotopes of radium), is now widely used in dating corals, deep sea sediments, volcanic rocks and cave deposits that are 300,000 years old or younger. This dating technique has revolutionized our understanding of the large scale climatic and environmental changes of the ice ages. A great deal of work in this area has been done at Yale as part of the research program in the present geology and geophysics department.

The recognition of the importance of the discoveries of Boltwood applicable to geochronometry was not continued at Yale, however, for many years. Much like the transfer of the insights of Gibbs, it had to wait until the late 1950s before the exploitation of these Yale discoveries occurred at Yale.

Joseph Barrell (1869-1919): Although Joseph Barrell lived for only 50 years he contributed important concepts to our understanding of the way Earth was formed and changed (Schuchert, 1925). He started working initially on addressing mining problems, but he was transformed into a generalist with profound understanding of the way the Earth works after he came to Yale as a graduate student. Many of his insights came from reviewing and analyzing ideas presented by others. His understanding of the role of subaerial deposits in the geologic record made him aware of the importance of paleoclimate and paleogeography. He understood that producing the large conglomerate deposits of several hundred million years ago in the Appalachians required a very large mountain range to the east where only an ocean exists now. He did not accept our contemporary view of plate tectonics but he did realize that the oceans might have developed to separate continents as the result of volcanic eruptions and loading. Although the concept was properly challenged by others who indicated that to make his plan viable the continental material under the accumulating basalt would have to be removed, it was an important contribution to global tectonics.

Barrell also propounded the view that Earth accumulated hot as the result of gravitational heating during accumulation. The idea was directly opposite to the idea of the slow dust accumulation model espoused by most other planetologists. We now know that Barrell was right and that influences our fundamental ideas of planetary origin and history.

Barrell was a geologist who was essentially the transition scientist needed as new physical knowledge grew and revolutions in such matters as the discovery of radioactivity and the understanding of the operation of physical laws on a grand planetary scale were understood.

Charles Schuchert (1858-1942): Of all the scientists discussed in this essay only Charles Schuchert did not receive his education at Yale. Indeed his formal education stopped when he was 13 years old because of family needs. Everything that he learned about the field in which his fame was to be made, paleontology, was self learned through diligent collection and observation. So skilled had he become in his chosen field that he was appointed a Yale professor in 1904 and curator of geological collections at Peabody Museum at Yale (the museum founded under the regime of Othniel C. Marsh).

Aside from being an invertebrate paleontologist of great renown, especially for his study of brachiopods, he was also the developer of the field of paleogeography. He and Barrell, colleagues and close friends, were responsible for reconstructing the past terranes using physical and fossil stratigraphic evidence. For Schuchert the development of the field of paleogeography was the result of an attempt to make order of the myriad of fossil data that had been collected by him and the other paleontologists. Interestingly this approach provided some of the best evidence for what was to develop into the theory of continental drift and its present expression as plate tectonics. Schuchert, however, did not believe in continental drift as he saw it violating the cherished principle of uniformitarianism. The importance of his contribution to the development of the field was taking the debate seriously despite rejecting it. Also the painstaking synthesis of fossil data to form the paleogeography base of our knowledge of past continental connections was ultimately to be used by the proponents of continental drift as some of the strongest evidence (Oreskes, 1999).

Yale's role in educating Americans in the fundamentals of geology through books is one of its principal contributions to this day. Although James Dwight Dana wrote several texts addressing the major problems of geology in the nineteenth century, not until the twentieth century was the primacy of Yale as the tutor to the nation in geology established. In l915 Charles Schuchert together with his Yale colleague, L.V. Pirsson, wrote "A Text-book of Geology" (New York, John Wiley & Sons). This book was the first in a series with successive authors from the Yale faculty that taught many generations of Americans all about geology. The original textbook consisted of two volumes, one called physical geology, the other historical geology, which subsequently took on separate lives of their own. When the senior author came to Yale in 1956 the physical geology text was written by Chester Longwell, Adolph Knopf, and Richard Foster Flint. The historical geology text was being transformed from being written by Charles Schuchert and Carl O. Dunbar to sole authorship by Dunbar since Schuchert had died many years earlier. These classic texts in geology were called the Yale geology books and virtually monopolized the market. There are now so many books on the expanding field of the earth sciences that it is hard to imagine the dominance that the Yale texts had in the education of several generations of students.

References:

Gaines, R. V., Skinner, H. C. W., Foord, E. E., Mason, B., and Rosenzweig, 1997, Dana's new mineralogy: The system of mineralogy of James Dwight Dana and Edward Salisbury Dana, eighth edition. New York, John Wiley & Sons.

Kovarik, A. F., 1929, Bertram Borden Boltwood, 1870-1927. National Academy of Sciences, Biographical memoirs, vol. 14, third memoir.

Narendra, B. L., 1978, The Peabody Museum meteorite collection: a historic account. Discovery vol. 13, no.1, p. 10-23 (Peabody Museum of Natural History, Yale University).

Newton, H. A., 1890, Professor Elias Loomis. American Journal of Science, third series, vol. 39, no. 234, p. 427-455.

Oreskes, N., 1999, The rejection of continental drift: theory and method in American earth science. New York, Oxford University Press.

Schuchert, C., 1925, Joseph Barrell, 1869-1919. National Academy of Sciences, Biographical memoirs, vol. 12, first memoir.

Skinner, B. J., and Narendra, B. L., 1985, Rummaging through the attic, or, A brief history of the geological sciences at Yale. Geological Society of America, Centennial special volume 1, p. 355-376.

Wheeler, L. P., 1962, Josiah Willard Gibbs: the history of a great mind. New Haven, Yale University Press, p. 91-92.