Popular Science Monthly/Volume 35/July 1889/Sketch of Henry Carvill Lewis
ALTHOUGH Prof. Lewis died at an age when men usually have hardly more than begun to produce matured work, his name had already become associated with the solution of a most important geological question, and he was recognized as one who had led the science another step forward.
Henry Carvill Lewis was born in Philadelphia, November 16, 1853, and died in Manchester, England, July 21, 1888. He was descended from an ancient patrician family, the Ludewigs, of the free imperial city of Hall, in Swabia, who are mentioned as having occupied as early as the fourteenth century responsible positions as military and civil officers in their city and in the Holy Roman Empire. In the beginning of the eighteenth century, the sons of his ancestor, Johann Peter Ludewig, appear as distinguished in arms and letters. One of them, Johann Peter von Ludewig, besides having other dignities, was a learned jurist and historiographer and poet laureate of the empire, and the author of many historical and legal works. His own ancestor of this generation, Johann David Ludewig, was connected with military and court life. His great-grandfather removed to America in 1784 and anglicized his name to Lewis. His grandfather, John F. Lewis, and his father, F. Mortimer Lewis, were engaged in the East India trade. The latter, since retiring from business, has been actively engaged in various philanthropies in connection with hospitals and benevolent institutions, and is now President of the Pennsylvania Institution for the Deaf and Dumb and of the Children's Hospital of Philadelphia. An incident that occurred when Henry Lewis was little more than an infant is mentioned by his biographer as showing an early inclination toward geological studies. He was found, while on a visit to the country, digging in the gravel-walk with a spoon, and, when asked why he was doing it, replied that he "wanted to see what was underneath." This may have been only a manifestation of childish activity which under other circumstances might not have been noticed and have passed without influence upon his career; but his father and his maternal grandfather, Mr. Henry Carvill, were quick to observe the direction of the dawning intelligence of the boy, and to cultivate whatever profitable tastes he might show. The generous interest taken by his father in fostering the bent of his son's mind toward research deserves, in fact, special recognition and acknowledgment. As soon as his son displayed earnest leanings in this direction, Mr. Lewis provided every facility for helping him in his favorite studies. Instead of attempting, as too many parents might mistakenly have done, to divert him from this to a more "practical" line of pursuits, he fitted up for him a well-furnished chemical laboratory and workshop; and this laboratory was through all his life a favorite retreat of Carvill Lewis's, to which it was his delight to introduce his scientific friends. His interest in mineralogy and geology assumed a more definite and controlling shape when he was about twelve years old, when Dr. Isaac Lea gave him some specimens as the foundation of a collection, and stimulated him to go on studying them. A year later he and some playmates formed a scientific society, which continued in existence and of which he remained a member till 1875, when it disbanded. Having been graduated from the University of Pennsylvania in 1873 with the highest honors in the classical course, he took a post-graduate course of three years in the natural sciences. For several years after his graduation he divided his time almost equally between geology and astronomy. Twenty-nine communications by him are recorded in the "Proceedings of the Mineralogical and Geological Section of the Academy of Natural Sciences of Philadelphia," from 1877 to 1879. He gave to the American Association in 1877 a description of an aurora and of the zodiacal light as observed by him in May of that year, and notes by him on the zodiacal light were published in the "Proceedings of the American Association" and in the "American Journal of Science" in 1880. In 1879 he joined the Geological Survey of Pennsylvania as a volunteer member, and continued associated with it till 1884. In connection with this work he investigated the surface geology of the southern part of the State, and began the tracing of the great terminal glacial moraine with which his name is most closely associated, determining its course through the northern part of Pennsylvania. In all these researches, as well as his studies in mineralogy and petrology—notably in those relating to the diamond and to the archæan rocks—he was moved by an earnest spirit of independent inquiry, and afforded a living illustration of the force and application of his motto, "Truth for authority, not authority for truth." The controlling force of this principle in his life-work is emphasized in the simple record on his tombstone in Walmsley church-yard, Bolton, "He loved the truth."
In 1880 Mr. Lewis was elected Professor of Mineralogy in the Academy of Natural Sciences, Philadelphia; and in 1883, Professor of Geology in Haverford College. He held both of these positions at the time of his death. From 1885 to 1887 he was occupied during the Winters in petrologic studies in Heidelberg with Prof. Rosenbusch, and during the summers in field-work on the glacial geology [of England, Wales, Ireland, Switzerland, and northern Germany. The winter and spring of 1887-'88 were spent in this country, partly in visiting the places in the Southern States where diamonds have been found, in continuance of his investigations on the origin of that gem. He had read papers on the subject at the meetings of the British Association in 1886 and 1887, and was planning to present his further results at the next meeting of that body; after which he hoped to carry on his glacial studies in Norway and other parts of Europe.
He sailed, with Mrs. Lewis, for Europe, on the 3d of July, 1888. He was affected during the latter part of his voyage with symptoms of illness, which developed, after he reached Manchester, England, into typhoid fever. From this he died on the 21st of July. Prof. G. F. Wright, author of "The Ice Age in North America" (New York, D. Appleton & Co., 1889), who was associated with him in the investigation of the terminal glacial moraine, has furnished the estimate which follows, of the general value of his work. The more particularized review of his glacial investigations with which this paper continues, has been furnished us by Mr. Warren Upham, who was also the author of a sketch of Lewis in the "American Geologist."
"It is impossible," says Prof. Wright, "to overestimate the value to the world of such a career as Lewis set before him, and already at his early death had largely realized. His vigor of body and mind, pleasing address, liberal education, high social position, and abundant means, insured to him flattering success in almost any direction. He could easily have attained eminence in the politics of his State and nation. He could have entered upon a business career with fair prospect of becoming a millionaire. Or he could have settled down, as the majority of those thus situated do, to the seductive pleasures of society, and have been one of its chief ornaments. Instead of this, he threw all the resources of his nature and of his position into the most laudable work of enlarging the stock of the world's knowledge.
"The leisure hours of his boyhood were spent in his laboratory and in roaming over the hills in the vicinity of Philadelphia in search of facts to explain their origin. After graduating from the university, he offered himself as an assistant to the Geological Survey of the State, and for one or two seasons accompanied the surveyors in the dull routine of their work. He afterward was commissioned to prosecute independently investigations into the nature of the gravel deposits of the rivers entering the Atlantic between New York and Norfolk, Va. It was with the results of these youthful investigations that he came to the meeting of the American Association for the Advancement of Science at Boston, in 1880, with two or three papers which at once attracted the attention both of that body and of the wider audience reached by the printed reports. Lewis was specially delighted on that occasion by the approval of his work which was given by the venerable Prof. W. B. Rogers, then at the head of the Massachusetts Institute of Technology, and for so long a time connected with the Geological Survey of Pennsylvania and the adjoining Appalachian region.
"During all his earnest search for the truths of Nature, Lewis was stimulated by the thought that man does not live by bread alone, but that he who ministers to the mental wants of the race by discovering truth and bringing it within reach of the general apprehension is as truly a philanthropist as he who ministers to their bodily comfort. In all these aims it is gratifying to know that his wife most heartily coincided. A great truth of Nature, like the wonderful history of the Glacial period, when it finds its way into the school-books of the children and into works of general literature, is of incalculable utility in the intellectual development of mankind."
"Prof. Lewis first became specially interested," writes Mr. Upham, "in the glacial drift and its terminal moraine during the latter part of the year 1880, when, in company with Prof. G. F. Wright, he studied the remarkable osars of Andover, Mass., the gravel of Trenton, N. J., containing palæolithic implements, the drift deposits of the vicinity of New Haven, Conn., under the guidance of Prof. Dana, and finally the terminal moraine in eastern Pennsylvania between the Delaware and Lehigh Rivers. The following year Profs. Lewis and Wright traversed together the southern border of the drift through Pennsylvania from Belvidere, on the Delaware, west-northwesterly more than two hundred miles across the ridges of the Alleghanies, to Little Valley, near Salamanca, N. Y., and thence southwesterly one hundred and thirty miles to the line dividing Pennsylvania and Ohio, which it crosses about fifteen miles north of the Ohio River. The report of this survey of the terminal moraine was published in 1884, forming Volume 2 of the reports of progress of the Second Geological Survey of Pennsylvania.
"With the similar exploration of other portions of this great moraine done a few years earlier by Prof. Chamberlin in Wisconsin, Profs. Cook and Smock in New Jersey, and Mr. Warren Upham in Long Island, thence eastward to Nantucket and Cape Cod, and also in Minnesota, it completed the demonstration of the formation of the North American drift by the agency of land-ice.
"The observations of the moraine in Pennsylvania, detailed in this volume, are summarized by Prof. Lewis as follows: 'The line separating the glaciated from the non-glaciated regions is defined by a remarkable accumulation of unstratified drift material and bowlders, which, heaped up into irregular hills and hollows over a strip of ground nearly a mile in width, forms a continuous line of drift-hills (more or less marked) extending completely across the State. These hills vary in height from a few feet up to one hundred or two hundred feet, and, while in some places they are marked merely by an unusual collection of large transported bowlders, at other places an immense accumulation forms a noteworthy feature of the landscape. When typically developed this accumulation is characterized by peculiar contours of its own—a series of hummocks, or low, conical hills, alternate short, straight ridges, and inclosed shallow basin-shaped depressions, which, like inverted hummocks in shape, are known as kettle-holes. Large bowlders are scattered over the surface, and the unstratified till which composes the deposit is filled with glacier-scratched bowlders and fragments of all sizes and shapes.'
"From its lowest point in Pennsylvania, where it crosses the Delaware, 250 feet above the sea-level, this terminal moraine extends indiscriminately across hills, mountains, and valleys, rising over 2,000 feet above the sea in crossing the Alleghanies, and attaining the maximum of 2,580 feet on the high table-land farther west, being there 'finely shown at an elevation higher than anywhere else in the United States.'
"Preliminary outlines of Prof. Lewis's work on the glacial drift of England, Wales, and Ireland are given by his papers in the reports of the British Association for 1886 and 1887; and the first of these also appeared in the 'American Naturalist' for November, and the 'American Journal of Science' for December, 1886. Their most important new contribution to knowledge consists in the recognition of the terminal moraines formed by the British ice-sheet, which Lewis traced across southern Ireland from Tralee on the west to the Wicklow Mountains and Bray Head, southeast of Dublin; through the western, southern, and southeastern portions of Wales; northward by Manchester and along the Pennine chain to the southeast edge of Westmoreland; thence southeast to York, and again northward nearly to the mouth of the Tees; and thence southeastward along the high coast of the North Sea to Flamborough Head and the mouth of the Humber. It is a just cause for national pride that two geologists of the United States—Lewis in Great Britain in 1886, and Salisbury the next year in Germany—have been the first to discover the terminal moraines of the ice-sheets of Europe. Like the great moraines of the interior of the United States, those of both England and Germany lie far north of the southern limit of the drift.
"Another very important announcement by Prof. Lewis relates to the marine shells, mostly in fragments and often worn and striated, found in morainic deposits and associated kames 1,100 to 1,350 feet above the sea, on Three Rock Mountain, near Dublin, on Moel Tryfan in northern Wales, and near Macclesfield in Cheshire, which have been generally considered by British geologists as proof of marine submergence to the depth of at least 1,350 feet. These shells and fragments of shells, as Lewis has shown, were transported to their present position by the currents of the confluent ice-sheet, which flowed southward from Scotland and northern Ireland, passing over the bottom of the Irish Sea, there plowing up its marine deposits and shells, and carrying them upward as glacial drift to these elevations, so that they afford no testimony of the former subsidence of the land. The ample descriptions of the shelly drift of these and other localities of high level, and of the lowlands of Cheshire and Lancashire, recorded by English geologists, agree perfectly with the explanation given by Lewis, which indeed had been before suggested, so long ago as in 1874, by Belt and Goodchild. This removes one of the most perplexing questions which geologists have encountered, for nowhere else in the British Isles is there proof of any such submergence during or since the Glacial period, the maximum known being 510 feet, near Airdrie, in Lanarkshire, Scotland. At the same time the submergence on the southern coast of England was only from ten to sixty feet, while no traces of raised beaches or of Pleistocene marine formations above the present sea-level are found in the Orkney and Shetland Islands. The work and writings of Prof. Lewis emphasize the principle that glacially transported marine shells and fragments of shells, which occur in both the till or bowlder-clay and the modified drift in various parts of Great Britain, are not to be confounded with shells imbedded where they were living, or in raised beaches, for only these prove the former presence of the sea.
"The drift deposits of England south of the terminal moraines traced by Lewis were regarded by him as due to floating ice upon a great fresh-water lake, held on the north by the barrier of the ice-sheet which covered Scotland, northern England, and the area of the North Sea, and on the southeast by a land-barrier where the Strait of Dover has since been eroded. Under this view he attributed the formation of the Chalky bowlder-clay in East Anglia and of the purple and Hessle bowlder-clays in Lincolnshire and much of Yorkshire to lacustrine deposition, and believed that there was only one advance and recession of the ice-sheet. But shortly after the British Association meeting in 1887 his observations on Frankley Hill in Worcestershire and thence westward led him to accept the conclusion, so thoroughly worked out by other glacialists both in America and Great Britain, that there were two principal epochs of glaciation, divided by an interglacial epoch when the ice-sheet was mostly melted away. There can be little doubt that the continuation of Lewis's study of the drift in England, if he had lived, would have soon convinced him of the correctness of the opinions of Searles V. Wood, Jr., Mr. Skertchly, and James Geikie, that land-ice during the earlier Glacial epoch overspread all the area of the Chalky bowlder-clay, extending south to the Thames. Small portions of northern England, however, escaped glaciation both then and during the later cold epoch when the terminal moraines mapped by Lewis were accumulated; and these tracts of the high moorlands in eastern Yorkshire and of the eastern flank of the Pennine chain are similar to the driftless area of southwestern Wisconsin.
"Comparison of the drift in the United States and Great Britain enabled Prof. Lewis to refer the British modified drift, both that often intercalated between deposits of till and that spread upon the surface in knolly and hilly kames and more evenly in plains and along valleys, to deposition from streams supplied by the glacial melting, the material being washed out of the ice-sheet. These beds, however, are to be carefully distinguished from those of interglacial and post-glacial age. It is greatly to be regretted that this sagacious observer was not spared for the fulfillment of his plan of yet more extended study of European glacial deposits in the light of his wide knowledge of the terminal moraine and other drift formations in this country."
Prof. Lewis was a member of the American and the British Associations; of the American Philosophical Society, the Academy of Natural Sciences, and the Franklin Institute, in Philadelphia; of the Geological Society of Liverpool; and a Fellow of the Geological Societies of London and Germany.
He was married in 1883 to a daughter of the late William Parker Foulke, of Philadelphia, who, with a daughter, survives him, and will transfer his unfinished papers, for completion, to the distinguished geologists who have generously offered their assistance. He possessed a strong Christian faith, and was an active member of St. Michael's Protestant Episcopal Church, Philadelphia, of whose Sunday school he was for many years a teacher, and for a long time superintendent. He had the happy faculty of imparting knowledge to those whom he taught, and in making his instructions interesting and agreeable. With a high character, a pure standard of manhood, fine mental and physical powers, a wide range of scholarship, a happy, genial, and enthusiastic temperament, rare perseverance and industry, and a lofty devotion to the interest not only of science but of mankind, his life seemed to promise the widest usefulness and honor.
The following list of Prof. Lewis's published papers is abbreviated from the "American Geologist":
1876. "On Strontianite and Associated Minerals in Miffin County, Pennsylvania."