Popular Science Monthly/Volume 31/July 1887/Sketch of Isaac Lea
|SKETCH OF ISAAC LEA.|
FEW naturalists have enjoyed a longer working-life, or been able to make it more fruitful in finished achievement, than Isaac Lea. His first paper, being a simple account of the minerals then known to exist in the vicinity of Philadelphia, was published in 1818. Additions to this contribution were made but slowly for a few years, but as the list swelled they become frequent, giving evidence of indefatigable industry in research; and the last paper, standing as No. 279 on the catalogue, is dated 1876, closing a record of fifty-eight years of productive activity. During most of this time Dr. Lea was associated in the conduct of a large publishing-house, and was only able to give his hours of leisure to science.
Isaac Lea was born in Wilmington, Delaware, March 4, 1792. He was descended from ancestors who came over from Gloucestershire, England, with William Penn, and were described as "a couple of noted and valued preachers." He was the fifth son of James Lea, a wholesale merchant, and was at first put in a course of classical instruction at the academy in Wilmington, in preparation for the medical profession. This purpose was afterward given up, and, when he was fifteen years old, Isaac was sent to Philadelphia to engage in mercantile business in association with his brother. He had inherited a strong taste for Nature from his mother, and found a congenial spirit in Professor Vanuxem, then also a youth, with whom he formed the habit of making collecting excursions around the city. The two companions were soon led, by what they found and observed, to inquiry into the composition and structure of the rocks; they had to pursue it at first without any guidance, but in a short time became acquainted with the mineralogical collection of Dr. Adam Seybert. A diversion to their pursuits was given by the occurrence of the war with Great Britain in 1812. They joined a volunteer rifle company, which offered its services to the Governor. Although the company was disbanded without being called into service, young Lea had, by joining it, engaged enough in war to violate the principles of the Society of Friends, and he lost his birthright in it. Among the excursions which the two youths made was one to the coal-mines near Wilkesbarre, where they found slates containing mollusca, which Lea described forty years afterward in the "Journal of the Academy of Natural Sciences." They walked back, over the Pocono Mountain through the Wind-Gap, where Lea found the first trilobite they had ever seen, and down the Delaware River. In 1815 they were both elected members of the Philadelphia Academy of Natural Sciences, and began to take active parts in its proceedings; and in this society Mr. Lea read his first paper, already referred to, embodying the results of many years of close observation which the friends had made upon the rocks during their excursions.
On the publication, in 1818, of Professor Silliman's prospectus of the "American Journal of Science," Mr. Lea procured the names of fourteen subscribers to the journal—an act which Professor Silliman afterward declared "was the turning-point of the scheme"; for, receiving such encouragement from a person with whom he had no personal acquaintance, he was sure the journal would be successful. Mr. Lea contributed several papers to the early numbers of this journal, at the editor's request; but the article of this period which is perhaps most worthy of special mention, is one that he published in 1828 in the "American Quarterly Review," on the Northwest Passage, in which he expressed the opinion that, if the passage were ever made, it must be, as was indicated by the direction of the currents, from west to east. This hypothesis was verified in 1852 by Captain McClure's making the passage in the direction described.
As Mr. Lea advanced in his geological studies, he found that it was necessary to know something of shells. In order to study their genera as described by Lamarck, he imported a large collection of shells from China. He soon became interested in this branch of the science, and ultimately made it the leading object of his researches. A collection of several species of Unio, including some beautiful and rare specimens, was sent to the Academy of Natural Sciences, in 1825, by Major Long, of the Engineer Corps, who had obtained them in dredging the channel of the Ohio River below Louisville. At about the same time, Mr. Lea's brother Thomas, having engaged to look after the shells in the vicinity of Cincinnati, where he was living, shipped a barrel of shells of rare beauty, including six new species. The description of these specimens—"Description of Six New Specimens of the Genus Unio"—presented to the American Philosphical Society in 1827, formed the first of that long series of papers on the Unio and allied shells which constitute the chief of Mr. Lea's works. Yet, at the time he presented it, he had no thought that he should ever have another word to say on the subject, for at that time no one conceived the infinite variety of species of the family which American waters are now known to contain. As a side-result of Mr. Lea's interest in the Unios may be mentioned the conversion of his brother from an indifferent barreler of shells for another to an enthusiastic student of land-shells and botany, and to be the author of a monograph on "The Plants of Cincinnati."
Dr. Lea spent the traveling season of 1832 in Europe, where the journal of his excursions is a record of successive introductions to famous scientific men, and interesting conversations with them, in which he was never the only one who received information. In London he attended a meeting of the Geological Society, and met most of the leading geologists of Great Britain. At Oxford, he attended the second meeting of the British Association, over which Dr. Buckland presided. Meeting Dr. Buckland afterward in London, the conversation turned upon the quantity of coal in the United States. Dr. Buckland thought we had very little coal. Dr. Lea pointed out on a map the coal-fields of the United States as they were then known. After several hours spent in the examination of the matter, Dr. Buckland taking notes all the time, the distinguished geologist remarked, as he took his leave to meet an engagement, that England had enough coal to supply the United States when its supply should fail. Dr. Lea replied that the quantity of anthracite and bituminous coal was almost unlimited in North America, and promised to send him maps and sections that would satisfy him upon the subject. He fulfilled his promise after he returned home, and, upon the evidence thus afforded, Dr. Buckland presented a paper to the next meeting of the British Association on the extent of our coal-supply. At the British Museum, by the request of Dr. Gray, Dr. Lea went over the collection of the Unionidæ, arranged and named them correctly, and added some new species from the United States. He called, in Paris, on Baron Ferussac, the eminent student of terrestrial and fluviatile mollusca, who was then engaged in preparing his great work on the Unionidæ. During the conversation the baron "complimented Dr. Lea by saying that he could not go on with his work until he (Dr. Lea) had finished his memoirs." Dr. Lea afterward spent several hours in going over the baron's collections, which contained Unionidæ from Brazil, Syria, Turkey, and Egypt, and rearranging it, cutting down the species and forming numerous synonyms. Afterward, he met Blainville, Ferussac, and others at the Jardin des Plantes, to arrange and name all the Unionidæ of the collection there, to which he added fourteen species. From Studer, the elder, in Berne, he received the last copy in the author's possession of his work on the land and fresh-water shells of Switzerland, and compliments on the papers he had himself written. At Paris, again, he examined the Unionidæ in the Duc de Rivoli's collection, which contained all those of Lamarck, and was thereby able to identify all of Lamarck's species in his subsequent memoir. Calling on M. Gay by invitation, he was shown all the mollusca which that naturalist had collected in his travels, and was invited to select a specimen of each. Thus he found the most eminent naturalists everywhere, on the strength of the few papers he had published on American mollusca, ready to welcome him as one of themselves, and to receive instruction from him. Their general message to him was to go on with the investigations he had begun, with the assurance that no naturalist in America or Europe had the advantages that he possessed.
On returning home in November, 1832, he found that he had been anticipated in a work he should have done on the Tertiary shells of Alabama, but, having specimens of the species in his cabinet, he prepared a paper, "Contributions to Geology," which he presented to the Academy of Natural Sciences in August, 1833. It contained two hundred and twenty-one species. His "Synopsis of the Family Naïades," published in 1836, and afterward supplemented and expanded, is said to have settled satisfactorily to most conchologists the synonymy of the species. On receiving it, Prince Charles Bonaparte expressed a desire to see all parts of zoölogy treated in the same manner. In 1849 Dr. Lea presented a paper on the foot-marks of the reptile Sauropus primævus, found by him in the red shales at Pottsville, Pennsylvania, seventeen hundred feet below the conglomerate, which was of interest on account of the discussion it excited as to the age of the fossil. The foot-prints were assigned to the old red sandstone, while Professor Agassiz had declared that he did not believe that any air-breathing animals had existed before the new red sandstone. The discussion was kept up for several years, in the course of which Dr. Lea reiterated and maintained his position that the fossil was what he represented it, and that the formation in which it was found was the one indicated by Rogers as No. XI. Its interest has since been diminished by the discovery and authentication of fossils of air-breathers in still older formations. Another series of papers of peculiar interest was that concerning the fossil saurian of the new red sandstone (Clepsysaurus Pennsylvanicus).
Having retired from business in 1851, Dr. Lea made another visit to Europe in 1852. Many of the incidents of his previous visit were substantially repeated, but in large part with naturalists of another generation than those whom he had met before. At Paris he arranged and named the Unionidæ in the cabinets of the eminent conchologists Boivin and Petit. He called upon Dr. Chenu to look for the original specimen of Mulleria of Ferussac, which had never been figured, but simply described as being in Lamarck's collection. "He told Dr. Chenu that he thought it must have been mixed with the Etheria, of which the collection had many specimens. Dr. Chenu declared this could not be so, or he would have seen it. As soon as he pulled out the drawer, Dr. Lea saw at a glance the identical specimen which Ferussac had described. He took it up and declared this to be it. Both the naturalists were surprised and delighted. ... Thus Dr. Lea's theory of the genus Acostea, of D'Orbigny, was complete—it was a Mulleria." At Vienna he showed the Austrian naturalists some features in their species and specimens which had escaped their eyes. At Berlin he found Humboldt and other distinguished men of science much interested in what was going on in geology in the United States. At a dinner with the Philosophical Club in London, Sir Charles Lyell gave him credit for being the first and only one who had yet observed an air-breathing animal in so ancient a rock as that in which the Sauropus primævus occurred, and added that the Clepsysaurus Pennsylvanicus was the first discovery of bones in the new red sandstone, although a jaw of a similar animal had since been found. Colonel Sabine exhibited a bottle which he supposed had come through Behring Strait from Japan, which Dr. Lea was able to claim as a verification of his theory of a west-to-east Arctic current.
On his return home in November, 1853, Dr. Lea found an accumulation of correspondence and specimens awaiting his attention that hardly diminished, so incessant were the fresh arrivals, during the remainder of his active life, or for twenty-five years. Among his new Southern and Southwestern correspondents was Bishop Elliott, of Georgia, who became greatly interested in the mollusca of that State, and engaged others in interest in the subject and in collecting shells. The scientific researches of Dr. Lea were continued, with constant publications, until 1877, when a sudden illness which came upon him in Southern California disabled him from further vigorous work. He still, however, continued to add to his collections and perform such work upon them as his strength would allow. He gave much attention to the microscopic examination of quartz-crystals, with drawings and descriptions of the inclusions and markings of each, so that Professor H. Rosenbusch, in his work on the subject, mentioned him as having been the first in America to enter into microscopic mineralogy. He had engaged, since his return from Europe, in other branches of natural history than conchology. The elephant folio edition of the account of the fossil foot-marks near Pottsville elicited warm commendation for the beauty of its execution and illustration. In 1858 appeared a memoir on the embryology of the Unionidæ, giving descriptions and figures of thirty-eight species. In all of his papers he described eighteen hundred and seventy-two species of mollusks of various kinds, most of which were from the United States. The series was embodied in a private edition of thirteen volumes, with three indexes, which the author distributed among men of science and learned societies. Richard Owen, acknowledging the receipt of one of the volumes, said, "They represent a kind or class of labors the most genuine and important and lasting, in the hard endeavor to gain a knowledge of Nature." Professor Haidinger, of Vienna, said, on a similar occasion, that his work would "last as long as natural science shall be cultivated by mankind. The more it is compared and studied, the more appears your power of observation, your efforts in pursuing your object, your steadiness and perseverance." M. A. Boivin wrote, "You render a great service to science in devoting your time to the classification and description of the Unio." About ten thousand individuals were displayed in Dr. Lea's cabinet of Unionidæ, so arranged that each could be separately examined, and, in many instances, with a sequence from the youngest to the oldest, so as to exhibit the aspects of growth. His other cabinets contained nearly a thousand specimens of quartz-crystals, nearly five hundred of corundum, thirty-five drawers of the mica group, and several hundred sections of lamina prepared for the microscope.
In his ninety-fourth year Dr. Lea continued in good health, with his mental and physical faculties unimpaired; and in 1884 he was able to receive and entertain about two hundred members of the British Association at his cottage at Long Branch. He was President of the Academy of Natural Sciences in Philadelphia from 1853 to 1858, and was President of the American Association in 1860. The list given in his "Bibliography" of the society honors conferred upon him numbers twenty-eight titles, and concludes with an etc. A correspondent who maintained most intimate and confidential relations with Dr. Lea for more than twenty years, furnishes a sketch of his personal character and social life, from which we quote the following words:
"Possessing a mind of great vigor and culture, he was a most genial companion to those whose tastes and sympathies accorded with his own. He was an ardent admirer of the works of Nature; and his cultivated mind enabled him to perceive many qualities and properties in them, the beauties of which are not comprehended by a less gifted observer. Few objects escaped his notice. He possessed, in an eminent degree, a prompt and keen appreciation of the sublime and of the grotesque; and a speedy judgment in detecting merit or fraud, affectation or sincerity.
"Dr. Lea habitually, during a period of nearly half a century, spent many hours of the night in his studies and his writings, seldom relinquishing them before midnight. These night studies were continued, with little intermission, until he was nearly eighty years old; and they were gradually and finally abandoned only in compliance with the warnings of his medical adviser. Until Dr. Lea became enfeebled with age, at a late period in his life, it was a source of great delight to him to collect mineral specimens in Chester and Delaware Counties in Pennsylvania. His most frequent companions, on such occasions, were Mr. William W. Jefferis, formerly of West Chester, and the writer. No ardent school-boy manifested more enthusiasm in digging than he, when a fair prospect was afforded for obtaining specimens; and his well-trained eye quickly recognized a specimen, though covered with soil. He never permitted any person to clean his specimens excepting himself; and that operation he performed with great patience, in the most complete manner, in order to display all the beauties which the minerals possessed. He was familiar with nearly all the mineral localities in Eastern Pennsylvania. Many years ago the writer described a locality for minerals in Delaware County, which he supposed would be new to Dr. Lea, and received the following reply from him: 'I have crawled all over that locality, on my hands and knees, a half-dozen times, with good results every time.'
"Dr. Lea was a strong admirer of gems, and his familiarity with precious stones was so great that he was considered to be one of the best judges of them in this country. He devoted more time than any other mineralogist to the microscopic examination of the precious stones; the results from which were published, at various times, in the proceedings of the Academy of Natural Sciences. He possessed a large collection of precious stones from all the important localities in the world; and copious notes, in his own writing, are still attached to all the specimens.
"During the last few years of Dr. Lea's life, after he relinquished much of the active work in his mineral cabinet, his time was usually spent in his library, in the happy enjoyment of life, surrounded by his books referring to his favorite studies, mineralogy, geology, and conchology. He enjoyed especially the company of his scientific friends, and his interest in discussing scientific subjects was maintained until his final illness."
Another friend of Dr. Lea's expresses surprise that, in all the published notices of him, "no one has spoken of his wonderful powers of observation of Nature even in her minutest forms. You will pardon me if I say that I consider it one of his highest qualifications as a man of science. Nothing ever escaped his quick eye in the field or by the road-side when driving. Every tree, shrub, and flower, was full of interest to him, from which he ever imparted knowledge to his friends. In observing crystalline forms I believe he excelled others."
Another friend regards him from a different point of view, and says: "Something of his great-heartedness was revealed to even the casual observer. It found expression in form, and feature, and voice. Yet it was by those who knew him intimately that the social, affectional qualities of his nature were best perceived and most admired. Inheriting a loving spirit, and receiving the gentle impressions of a Christian home, he never lost his priceless dower. The demands of successful, enlarging business, the fondness for scientific study, the passion for scientific discovery, the allurements of fame, were wholly insufficient to make him other than amiable and self-forgetful. His home was the source and center of his delight. He gratefully acknowledged his indebtedness to those on whom he lavished his regard. During all the years in which he used even the night-watches for his investiations, the early hours of evening were spent, with free and joyous mind, in the midst of his family. He ever took more from himself than from others. Hospitality was the very genius of his house. With gentlest, heartiest courtesy his friends were welcomed to his fireside and his board. To those of scientific turn his rare and extensive scientific collections were opened with genuine delight. For those whose choice was in other directions, provision was made with equal care and gladness. Toward little children, and the young in general, his sympathies went forth with spontaneous freedom. He delighted to show to childish eyes, and to explain to childish comprehension, the beauties and marvels of Nature. Especially did he rejoice in giving encouragement to those who were struggling upward against great odds. The sight of such aspiration always awakened his enthusiastic interest. Not a few who to-day occupy positions of honor and usefulness owe their success to his appreciative, generous help. To envy his heart was wholly a stranger, and thus his friendships with men of science, both young and old, and with men great in other walks, were peculiarly tender and strong.
"In truth, his kindly interest included whatever affected the welfare of the race. He took pleasure in all honest effort. He exulted in all honorable achievement. He felt that he was personally indebted to whosoever made man better or more wise. In all social problems he took profound, unflagging interest. He sought to hold in view the progress of humanity in every land. In the alliance between religion and philanthropy and science he was a firm believer. He was confident that truth and right would triumph at last. To his perception the laws of Nature were the constancy of God's action, and Nature itself a transcript of the Eternal Mind."