Extract from beginning of chapter: Looking back over forty years of petrographical work, from 1879 to 1919, in what might be called the first half-century of modern petrography, the writer [Iddings] has been interested to recall the dominant impressions made upon his mind by personal intercourse with many workers who took an active part in the development of the science during this period, and by the reading and study of their writings which bore directly upon his own particular lines of research. The framework of such reminiscences may well be constructed of the published results of his own research efforts and speculations. That is, the attempt by the writer to narrate the purpose or occasion, as well as the essential ideas, in several publications on petrographical and related subjects properly involves a consideration of the part played by his colleagues, directly or indirectly, in the formation of ideas or hypotheses held by the writer, and recognition of the extent to which his colleagues may have been responsible for the taking up of some particular problem. It is interesting to note to what extent one may be indebted to others for suggestions both of petrographical conceptions and of lines of research, suggestions which may have been consciously or unconsciously conveyed by one's colleagues, and which may also have been consciously or only subconsciously accepted as such by the recipient. In many instances ideas are obtained through conversation or reading of others' writings, which are not definite at the time but develop and take shape subsequently.

Extract from beginning of chapter: GRADUATE STUDY AT YALE My first vivid impression of petrography as a definite study in itself was gotten by watching George Hawes 1 working with a microscope over thin sections of granite from New Hampshire. His enthusiasm, his radiant smile, the glow of his blushing cheeks, and the merry twinkle of his bright eyes as he turned from the microscope to explain its uses in determining the minerals, brilliantly illuminated like bits of stained glass in a church window, were my introduction to what seemed to me a most interesting subject. This was in 1878 when I was a graduate student in the Sheffield Scientific School 2 at Yale, and Hawes, an instructor in blowpipe analysis, was studying in one corner of his laboratory in the Peabody Museum the rocks of New Hampshire for Professor Charles H. Hitchcock. 3 Up to that time, my acquaintance with rocks was confined to definitions in Manual of Geology (J.D. Dana, 1874) and to collections of hand specimens and such material as one sees in buildings and monuments. As a boy I became familiar with the red sandstone and trap rocks of Orange, New Jersey, and encountered the same in the vicinity of New Haven, Connecticut. 4 Besides these I had seen the gneisses and schists of Manhattan Island, 5 and the garnet-bearing mica-schists along the Patuxent River in Montgomery County, Maryland. At this period, geology and mineralogy were for me merely a means to an end, namely, the profession of a mining engineer and the acquisition of a

Extract from beginning of chapter: EUREKA, NEVADA During May and June [1880], I worked as a temporary assistant to Hague on the United States Geological Survey, and on the first of July, I received my appointment as assistant geologist and felt duly elated. It had been King's plan that Hague should have charge of the Division of the Pacific Coast with headquarters in San Francisco, and that he should study the volcanoes of that region beginning with Lassen Peak. But it seemed advisable that his first work should be of a more utilitarian character, so he was commissioned to investigate the geology of the Eureka Mining District in central Nevada. 1 Leaving New York on the evening of the 16 th of July, we were joined in Utica, New York, by a tall, slender, red-whiskered young man who was said to be a promising paleontologist, who had already made a reputation out of his studies of Trenton trilobites, and who had spent the previous season in the Grand Canyon of the Colorado [River]. The next morning, I made the acquaintance of Charles D. Walcott 2 and commenced a lifelong friendship full of interesting experiences and pleasant memories. At the end of the sixth day, we reached Eureka, after a journey, which, for a young geologist, became more and more fascinating and instructive as it proceeded. Nowhere can one see geological structures on a grander scale or in more easily comprehended exposures than in the barren ranges of the Great Basin desert! Its simplicity as well as its nakedness

Extract from beginning of chapter: WASHOE AND THE RELATION OF ROCK NAMES TO GEOLOGIC AGE As previously mentioned, my frequent interviews with Becker over his collection of Washoe rocks impressed me with the close resemblance between rocks that he called pre-Tertiary and those he considered Tertiary, and led me to suspect the correctness of his distinctions and geological deductions. It seemed to me there were gradual transitions from one extreme of crystallization to the other, so I asked him to let me study the collection after he was through with it, which he willingly did. Arranging the rock specimens on a large table to conform to their position on his field map, it appeared at once that the boundary lines between what had been called different rocks did not separate specimens that were megascopically distinguishable from one another. Arranging the thin sections of rocks of various kinds according to the extent to which their groundmasses had crystallized, those with glass at one end of the series and the coarsest-grained ones at the other, it was found that there were transitions throughout each series and that the greater part of the so-called pre-Tertiary rocks had their exact equivalent among the Tertiary ones, some of the former being the coarsest-grained varieties, and some of the Tertiary ones being glassy. The age distinction had been based partly on the fact that some rocks were coarser grained than Tertiary rocks were supposed to be at that time and partly on the fact of more advanced alteration.

Extract from beginning of chapter: INTRODUCTION TO YELLOWSTONE The summer of 1883 found Mr. Hague and a large party of assistants entering upon the geological survey of Yellowstone National Park, a work that was to occupy them for years to come. For geological assistants there was Walter H. Weed, 1 a graduate of the Columbia School of Mines and a student of Professor Newberry. 2 Weed was selected as the most likely to become a geologist of the candidates, two of whom were Banks and Mudd. There were also George M. Wright, who had seen service under I.C. Russell 3 in the Great Basin, and myself whose previous fieldwork had been in Eureka, Nevada. William Hallock 4 was physicist with a mission to take the temperatures of the hot waters and study the action of geysers and hot springs. Frank A. Gooch, 5 who had been a chemist with Pumpelly's 6 Northern Transcontinental Survey, 7 was commissioned to study the thermal waters and spring deposits. Roland Holt acted in the capacity of assistant to the geological assistants, and C.D. Davis was secretary and disbursing agent to the geologist-in-charge. W.H. Jackson 8 was photographer and, as I was given a camera for the first time, proved a source of valuable instruction in the art and method of landscape photography. A man of excellent taste and judgment, he generously gave the beginner the benefit of his experience. After some time in Bozeman, Montana, purchasing mules, completing camp outfit, and laying in supplies, the party started for the park with animals and wagons so heavily laden

Extract from beginning of chapter: VOLCANIC CORES The discovery of this center of volcanic eruption, the core of what has since been called the dissected volcano of Crandall Basin (Iddings, 1893b), was one of those delightful experiences which happen occasionally in the lifetime of an explorer in any field of research. It was more delightful than the finding of the volcano core at Electric Peak had been two years before, because that had been anticipated in a measure by the discovery of a specimen of diorite in Wright's collection with its suggestion of what was to follow. The finding of the Crandall core was the outcome of several days' exploration of the volcanic ridges south, where dikes of andesite-porphyry and basalt were observed trending from various places toward one spot beyond a narrow steep ridge on the south side of Crandall Creek. On the crest of this narrow ridge dikes were very numerous and the focus of their directions very definite, so that we had great hopes that there might be a core of coarse-grained rocks exposed to view at no great distance. Camp was accordingly moved across the narrow ridge into the deep valley of Crandall Creek. The descent into the valley was a scramble for horses and pack mules, down the steep slope through small timber, and it was necessary to locate camp up the valley for grass and level ground. Not until the next morning could I explore the lower, narrow valley for the expected coarse-grained rocks. They appeared where they were

Extract from beginning of chapter: THE PROBLEM OF ROCK CLASSIFICATION The most debatable subject in petrology is that of rock classification, for it is not a matter of facts, but a question of their arrangement and systematic presentation. It is a matter of opinion as to the relative importance of various characters and relationships of rocks, and depends upon the objects or purposes for which any particular arrangement of petrographical facts is designed. The facts to be taken into consideration increase in number and complexity with the advancement of petrological knowledge, and the purposes of classifications vary according to the uses to which a classification is to be put, or according to what its users expect to get out of it. It is to be expected then that, in so new a branch of science as petrography, the classification of igneous rocks must be an unsettled and constantly shifting problem, not only because of improvements in petrological conceptions but on account of changing purposes on the part of petrologists. Starting with a classification that had been handed to me ex cathedra, I was not greatly concerned at first as to its construction and was occupied with problems of mineral identification; the composition, texture, and variability of igneous rocks; the existence of series; and the absence of distinctions referable to geological age. One of my first arguments on the subject of rock classification seems to have been with James D. Dana regarding quartz as a mineralogical factor in rock definitions. In a letter from him, Dana

Extract from beginning of chapter: Anyone who is studying dissected volcanoes and ancient lavas and breccia should have some acquaintance with active volcanoes and regions of modern volcanism. So I decided to visit Vesuvius and the Sicilian region, incidentally make the acquaintance of some of the British petrographers, and pay my respects to Rosenbusch in Heidelberg. By the end of February 1890, I was able to leave Washington for a two-month trip, going directly from New York to London via Southampton. Although I had never met Judd or Teall, they were hospitable enough, when they learned of my intention to stop in London on my way to the Continent, to invite me to come directly to their homes upon my arrival. Judd's note reached me before I left Washington, and Teall's caught me before I left the steamer at Southampton. It resulted in my spending a few days with Judd on my way out and in visiting Teall on the way back—a most memorable experience, quite as enlightening as the study of active volcanoes. IMPRESSIONS OF JOHN JUDD After a night at Charing Cross Hotel, I found Judd in his rooms in the “science schools,” 1 South Kensington, and received a most cordial welcome. Probably no British geologist equaled Judd in genial temperament and the ability to be entertaining. His manner was frank and outspoken; his attitude toward his colleagues was generous and not critical. He took an enthusiastic interest in petrography and expressed his opinions with such positiveness that one was led to believe

Extract from beginning of chapter: APPROACH TO THE CLASSROOM Penfield and Williams agreed in saying that their own experience was that they attempted to teach less and less each year—advice difficult for me to follow, as I couldn't teach less than I had up to that time. I could, however, attempt to limit myself to the elements; but even then teaching mineralogy at first required work on my part to keep one day ahead of the class. There was a wide range of possibilities in petrology, and I continued to range at will throughout my period of instructorship. Coming from an experience of unrestrained research as a student of rocks in the field and in the laboratory, I approached the problem of petrological instruction as a student among students, knowing how many things were as yet undetermined, how many were matters of opinion, and to what extent definitions of rock kinds (types) were arbitrary and illusory. Throughout my period of instruction at the university, I continued my own research as well as I could, and gave the students the results as they appeared from time to time, with consequent modifications of opinions from year to year. Upon one occasion, a student, who was attending a course a second season, remarked upon comparing his notebooks: “You didn't give the lectures this way last year.” “Of course not,” I replied, “they would lose interest to me if I did.” Whether this was the best method of conducting a course in petrology or in any other growing

Extract from beginning of chapter: MORE SUMMER FIELDWORK? The winter of 1892–1893 was an exciting period for members of the U.S. Geological Survey. Congressional criticism of Major Powell's administration had reached the point when the appropriation had been reduced, necessitating the retirement of several of the ablest geologists, and where the open antagonism of geologists not directly connected with the organization was awakened. A senatorial investigation of the management of Survey affairs had been ordered and a committee appointed, with Senator Wolcott 1 of Colorado as chairman. Letters from Washington told of the discontent and the struggle going on within the bureau. C.D. Walcott was called to the assistance of the director, who found the current setting too strongly against him and his former administrative associates. Van Hise also was taken into consultation as representing the wisdom of some of the western members of the Survey. A plan was proposed to reduce the allotment for topographic work and increase that of the geological division, and it was successfully put through Congress. The geologists who had been retired were reinstated, but the former arrangement of divisions was discontinued and the younger men given independent fields of work, where their individual abilities could have the opportunity to display themselves in competition with those of their former chiefs. In this readjustment, the director proposed that I should take up the exploration of the region immediately east of Yellowstone National Park, while Mr. Hague should devote himself to finishing his report on the geology of the park begun ten

Extract from beginning of chapter: SCANDINAVIA Of the many forms of benefaction derived from one's friends and colleagues, that of candid praise is probably the most appreciated by the recipient, and is least likely to remain unrecognized or to pass out of recollection, especially when it is accompanied by some token of distinction. It acts as recompense for prolonged effort and continued work and as an incentive to further endeavor. Its value is not to be neglected in reckoning one's obligation to one's friends. It is in this spirit I recall the satisfaction received from a letter of Judd's in which he wrote: 1 We are all very glad to be able to have your name enrolled among our foreign correspondents—though I do not deny that the pleasure was especially great in the case of Teall and myself, who have the pleasure of knowing you so well. Teall wrote: 2 I am glad you are pleased that we have made you a foreign correspondent of the Geological Society, but I cannot take the main credit of the achievement. Of course I voted for you and was pleased at the result, but you were most certainly elected on your merits. To tell the truth, I did not speak up for you as I should have done if you had not been my personal friend. I am not sure that I said anything in your favor either publicly at the Council or privately, but I will take this credit—I saw that you were dead certain to be

Extract from beginning of chapter: AGITATION OVER THE STATE OF IGNEOUS ROCK CLASSIFICATION The nomenclature of igneous rocks and their classification are subjects so intimately linked together that it is difficult to treat one without involving a discussion of the other. So it happened that in the agitation that arose during the 1890s over rock nomenclature, and found expression in the formation of an International Committee on the Nomenclature of Igneous Rocks, the question of classification became more and more prominent. The agitation culminated in the publication, in the Compte Rendu of the Eighth Session of the International Geological Congress in Paris in 1900 (Congrès Géologique International, 1901), of the Petrographical Lexicon, first published by Loewinson-Lessing (1894), and afterwards edited by himself and Barrois with the aid of an international committee of petrographers. The problem of classification took a course as surprising in its nature as it was unexpected in its method of solution. It was not international in its evolution, the proceedings of the committee on nomenclature demonstrating the hopelessness of attempting any constructive operations of an international character. As the sequel will show, it required the most intimate cooperation of closely affiliated colleagues at one on fundamental principles, and incidentally maintaining such amiable relations to one another as to be capable of sustaining considerable temperamental stress without undergoing permanent strain. In a letter from Judd, concerning papers by Cross (1892) and myself (Iddings, 1892d) on spherulitic crystallization, already referred to in another connection, he wrote: 1 On the question of nomenclature, too, I find

Extract from beginning of chapter: RECEPTION OF THE C.I.P.W. IGNEOUS ROCK CLASSIFICATION 1 It was to be expected that so radical a departure from current petrographical usage, and so novel a nomenclature as that proposed for the new system of rock classification, which was essentially a classification of magmas, would be very differently received by different petrographers according to their own views of igneous rocks and their individual temperaments. Indeed, we were not surprised that by some it was not received at all. “For,” as Moses exclaimed, “their rock is not as our Rock, even our enemies themselves being judges.” 2 They did not even acknowledge the receipt of the volume sent to them; at least, in a few notable instances no acknowledgment ever reached us. Canada Anticipating the shock, which might be occasioned in the minds of some petrographers, by the first sight of the full-fledged scheme, we wrote letters to a number of them stating the general plan of the undertaking and the method of its development. To Frank Adams, who had been taken into our confidence at an earlier period and, but for his inability to take part in our frequent conferences, would have been included in our committee, we submitted a draft of the complete proposition. His comment was: 3 The whole scheme is excellently set forth and the proposed classification seems to me to be good. Of course, as we all grumble at the introduction of new terms in the present classification, the setting forth of an entirely new series of names will

Extract from beginning of chapter: ARTHUR L. DAY AND FELDSPARS Some years after the cessation of the physical research work of Hallock and Barus for the U.S. Geological Survey, which had been inaugurated by Clarence King, and which had been discontinued because of insufficient appropriations by Congress, similar work was resumed by Arthur L. Day under the direction of George Becker in a small laboratory in the Survey building. One of the first problems attacked was that of the soda-lime-feldspars as products of dry fusion of their chemical components. It was proposed to demonstrate the correctness of Tschermak's theory of isomorphous mixtures of albite and anorthite molecules in the formation of a continuous series of soda-lime-feldspars (Tschermak, 1865), an assumption long since accepted as a fact by students of the microscopical characters of zonal plagioclases in rocks. It was proposed also to determine the physical constants of definite mixtures of the end molecules of the series. One of the first obstacles encountered, as I recollect it, was the impossibility of producing crystals of pure albite from a dry melt by any process at Day's command, and the doubt in that physicist's mind whether albite ever occurred in nature as a crystallization from an igneous magma, assuming that molten rock magmas were dry molten liquids. Subsequently, the high viscosity of albite substance at the conversion point from crystal to amorphous glass was demonstrated, the effects of admixture of other substances upon melting point and viscosity were taken into account, and the doubts of pyrogenetic albite were

Extract from beginning of chapter: THE DREAM Japan! The dream of my life since the time my father had imported a collection of curios and things Japanese, because of their artistic beauty and strangeness, and had given them to me, a boy in his teens, an incipient collector of everything interesting. The grace and beauty of Japanese decorations and utensils; the charm of the scenery as it appeared in pictures; and the attractiveness of the people and the friendliness of those I had met, developed a longing to visit the country and live among them as several of my older cousins had. The strangeness of the hermit people had been learned from the illustrations in the report of Commander Perry's 1 visit, and a familiarity with their [culture] had been gotten from a college mate in the Sheffield Scientific School, Mitsukuri Kakichi, 2 afterwards professor of biology in the university at Tokyo; he was a boy of fine culture who at college could write better English than I. There could be no feeling of aloofness toward a people having the qualities of Mitsukuri, and it was a source of sad regret when I reached Tokyo that my college mate was too ill for me to visit and soon passed away. Dr. Kochibe, formerly director of the Imperial Geological Survey, and I had met in Chicago and afterwards traveled together in Russia; and Professor Kotō 3 of the University of Tokyo had also visited me in Chicago. Japan, as a region of volcanoes, of lordly Fujisan, naturally excited the

Extract from beginning of chapter: KOREA The harbor of Fusan is surrounded by treeless, green hills, pitching steeply down to the sea. There was much evidence of new developments about the railroad terminus: quarrying, grading, and new buildings. The Koreans, squatting leisurely along the station wall in sunshine, their heads bound with colored handkerchiefs, reminded one of southwestern Indians. On the way up to Seoul, the country recalled Montana in some places, Nevada in others. In striking contrast to the moist and cloudy atmosphere of Japan, the air was brilliantly clear and the sky light blue. Near Fusan, granite hills were strewn with large blocks and boulders, dark with lichens, the ground between covered with light-yellow sand. Occasional villages of Korean huts, thinly thatched, on which were sunning golden pumpkins, rose above stone walls in crowded groups. Farther on were high mountains of dark-colored porphyry with barren talus slopes. Mountains and hills were steep, the topography accentuated. River valleys were flat, with small villages at the base of the slopes, the houses picturesque with blotches of bright red peppers drying on the roofs, and the gardens gay with small, red-blossomed trees. Plowing was being conducted in a primitive fashion, cattle served as pack animals, and laborers hauled boats up the broad stream beside which the railroad traveled. The sparse timber appeared to consist of scrubby pines and a few large deciduous trees. At times, magpies, fish hawks, herons, and swallows could be recognized from the train. In the high, central region near Kinsen station, low

Extract from beginning of chapter: HONG KONG Once more I was in the tropics at Hong Kong, where the botanical garden and the slope up to the peak furnished a glimpse of foliage and a sight of Indo-Malayan butterflies that whetted my appetite for the more luxuriant flora of lower latitudes. The picturesque mountains and land-locked harbor with vessels of all descriptions moving over its surface made a lasting impression and a striking climax to my Chinese wanderings. The trip from Shanghai had been made in a comfortable new Japanese steamer bound for London, the Kitano Maru, 1 a delightful nest in Japanese cleanness with a few Anglo-Saxon companions, American and British. In Hong Kong, by chance, I met a butterfly collector, net in hand, and found him a Swiss, willing to part with a fine assortment of butterflies he had collected in British Borneo, the Philippines, and southern China, while working as a civil engineer. Parts of two days were spent selecting all I wanted from his store of boxes, from which I hurried to catch the little steamer that was to take me to Manila. “Typhoon sitting to West,” as a Manila paper put it, is a very inadequate suggestion of what really took place out on the China Sea. Nothing sat. Everything tossed and pitched and whirled round, while I was reduced to the limpness of a stranded jellyfish upon a coral beach. To be sure, I held on like grim death to the mattress to keep from pitching out of the berth,