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of $25,000 a year for a period of twenty-five drawing and descriptive geometry; L. A years from Sir John and Lady Eaton. This Hamilton, analytical chemistry; H. B. Luther, is to provide for a full-time clinician in the civil engineering; C. S. Robinson, industrial department of medicine and a half-time clin- chemistry; R. H. Smith, mechanical engineerician in pediatrics.
ing; C. E. Turner, biology and public health. The court of governors of the University MR. WILLIAM MORRIS JONES, M.Sc., B.A., College of North Wales, at their meeting at has been appointed lecturer and experimentalBangor, appointed a deputation to wait upon ist in physics at the University College, the Board of Agriculture regarding the pro- Bangor. posal to have only two schools of forestry in Great Britain-one in Scotland and the other DISCUSSION AND CORRESPONDENCE either at Oxford or Cambridge. Fears were QUANTITATIVE CHARACTER-MEASUREMENTS expressed that if this was carried into effect
IN COLOR CROSSES it would mean the extinction of the forestry The writer, although working in plant and department in connection with the University not in animal breeding, has been struck with College of North Wales. It was felt that one the desirability of finding a more exact quanof the two new schools should be established titative measure of degree of distribution of in Wales, with its large area of forests. coat color in animal crosses. The following
is suggested. Photograph the animal in a SIR ARTHUR NEWSHOLME, K.C.B., who is now in the United States has accepted for the
centered position on its two flanks. On the academic year 1919–1920, the chair of hygiene photographic prints of the right and left sides
determine the area of the color markings in the new school of public health of the Johns
under investigation with a planimeter. These Hopkins Medical School.
areas, reduced to percentages of the entire CHARLES JOSEPH TILDEN, professor of civil area photographed, will give a quantitative engineering at Johns Hopkins University, has expression for the degree of extension of the been elected professor of engineering mechan- character markings. The writer would renics in Yale University and assigned to the
ture to suggest the following possibility in Sheffield Scientific School.
the study of the operation of an extension AUSTIN F. ROGERS and Cyrus F. Tolman,
factor. Let the photographic prints be ruled Jr., of the department of geology at Stanford off in square centimeter areas with India ink. University, have been promoted from associate
Then the relation of the color areas to the professors to professors.
region of the animal's anatomy can be defi
nitely established upon a quantitative basis. Morris M. LEIGHTON, Ph.D., Chicago, 1916,
This having been done for the parents, the has accepted a joint-position as assistant pro
operation of an extension factor could be fessor of geology at the University of Illinois
studied both quantitatively with respect to and as Geologist on the Illinois Geological
the amount of surface over which the factor Survey.
became operative, and topographically with At the Massachusetts Institute of Tech
respect to the location and range of its opnology the following assistant professors have eration in the progeny. If desired, it would been promoted to associate professorships:
be a comparatively simple matter to construct H. C. Bradley, department of drawing and a cross-wire screen behind which the animal descriptive geometry; C. E. Locke, department could be photographed, and which would thus of mining engineering and metallurgy, and
reproduce the areas to scale directly. N. C. Page, department of electrical engineer- In the study of inheritance in plants, the aping. The following instructors have been ap- plication of this method suggests itself very pointed assistant professors: J. B. Babcock, 3d, readily in color-inheritance in the seed-coats railroad engineering; S. A. Breed, mechanical of beans and other legumes. By photograph
ing the seeds with a photomicrographic appar- sories for habitat groups, and to secure skeleatus, enlarging them a sufficient number of tons, anatomical preparations of internal ortimes, it is easy to bring the markings within gans and parasites. the range of size where the use of the plani
HARLAN I. SMITH meter becomes a practical matter.
MUSEUM OF THE GEOLOGICAL SURVEY,
INFORMATION SERVICE FOR EXPERIMENTAL April 28
TO THE EDITOR OF SCIENCE: The Federation SURPLUS BISON FOR MUSEUMS
of American Societies for Experimental BiolTHERE is now a great surplus of male bison ogy, comprising the sciences of physiology, in the main Canadian herd at Buffalo Park, biological chemistry, pharmacology and exWainright, Alberta. This is the largest herd perimental pathology, is now organizing an of bison in the world, numbering 3,561 and is information service to serve as a medium of maintained by the Canadian government communication between persons seeking posiunder the administration of the Dominion tions for teaching or research and institutions Parks Branch of the Department of the In- that wish to fill vacancies in these sciences. terior.
Persons, whether members of the federation Besides these 3,561 bison, there are also 8 or not, and institutions desiring to avail themat the Rocky Mountains Park, Banff, Alberta, selves of the service may communicate with and 182 at Elk Island Park, Lamont, Alberta. Professor Edgar D. Brown, secretary of the In 1909, there was a total of 685 bison at executive committee of the federation, UniBuffalo Park, 118 were imported during 1910, versity of Minnesota, Minneapolis, Minn., and 1911 and 1912 from the Pablo herd in Mon- such information as is available will be suptana, and 10 bison cows from the Rocky plied without cost to the applicant. AppliMountains Park during the winter of 1913–14. cants are requested to supply the service with With the exception of these the increase has ten copies of their application, which should been due to natural causes.
cover the following points: It is said that elsewhere the percentage of 1. For the Person seeking a Position: age; male to female calves has been higher among college and university training; degrees rebison in semi-captivity within enclosed parks ceived; academic or other positions held; list than was the case when the herds freely of scientific papers published; membership in roamed the plains. This has proved to be scientific societies; position and salary desired; the case in the main Canadian herd, so that copies of letters of recommendation; names there is a great surplus of male bison that are and addresses of persons who can supply furnot needed for herd purposes.
ther information regarding the applicant; and It is proposed to dispose of these surplus any other information that the applicant demale bison for the nominal sum of $250 each sires to submit. to bonafide natural history museums of Can- 2. For the Institution desiring to fill a ada and the United States, and further in- Vacancy: title of vacant position; date to be formation can be obtained by such museums filled; requirements as to teaching or other from Mr. J. B. Harkin, Commissioner of routine work and research; salary to be paid; Dominion Parks, Department of the Interior, prospects of tenure of office and advancement; Ottawa, Ontario, Canada.
and any other information that the instituThis should prove a splendid opportunity tion desires to submit. not only to secure skins for mounted speci- The service does not undertake to recommens and groups, but also for museums to mend or to pass judgment upon applicants. send their preparators to Buffalo Park to It aims merely to serve as a clearing-house secure photographs, color sketches and acces- for such information as the above and to bring into touch with one another candidates In view of the ground covered, the chapter, for positions and vacancies to be filled.
comprising thirty-two pages, is somewhat
E. D. BROWN, scant. It could be improved also by the adUNIVERSITY OF MINNESOTA, Secretary dition of a series of outline maps of the con
tinent showing quantitatively where the more
important mineral commodities are produced, SCIENTIFIC BOOKS
and by the insertion of statistical tables and The Mineral Deposits of South America. By diagrams showing the relation of South Amer
BENJAMIN L. MILLER, professor of geology, ica's mineral output to that of the rest of Lehigh University, and JOSEPH T. SINGE
the world. Such aids in giving the reader WALD, associate professor of economic geol- generalized views of the continent as a whole ogy, Johns Hopkins University. New York, are conspicuously few in the present volume, McGraw-Hill Book Company, Inc. 1919.
but their urgent desirability should be conPp. 598, with 61 figs.
sidered by the authors when a new edition is South America is a continent richly en
planned. In places throughout the book there dowed with mineral resources: In Brazil are
is an unnecessarily abundant use of local the largest high-grade iron-ore deposits in the
Latin-American terms, for most of which the world; at Chuquicamata, Chile, is the largest authors could easily have substituted perfectly copper deposit in the world and the copper re
good English equivalents. sources of Chile are second only to those of
The remaining eleven chapters take up in the United States; the nitrates of Chile con
alphabetical order the countries of South stitute a world monopoly of that commodity;
America. The description of the mineral rethe tin lodes of Bolivia are by far the most
sources of each is introduced by a summary of productive in the world, their annual output production. In places some statistical errors being seven fold that of their nearest com
have crept in, as on page 77, where the outputs petitor; the world's greatest vanadium deposits of lead, zinc and tin of Bolivia are given in are in Peru; and the only considerable source
terms of metal, whereas the figures cited are of platinum outside of Russia is in Colombia.
in reality those of ore or concentrate. Nor is The mineral deposits are not only of great
it mentioned that the unit employed is the importance commercially but are also of deep
metric ton. These oversights are pointed out interest scientifically; and, as the present book
in passing, because current international staby Professors Miller and Singewald shows, tistics of mineral output commonly not more than a beginning has been made in
vitiated by similar lapses. The summary of solving the geologic problems they present. mineral production is followed by sketches of The book under review, as we are told in
the topographic and geologic features of the the preface, is “the outcome of an extended
country, of the distribution of the mineral trip through South America made by the
deposits, and of the occurrence of the chief authors in 1915." It is essentially a digest of mineral resources. This general treatment is available information on the mineral deposits followed by more detailed descriptions of the of that continent, supplemented, however, by important deposits and districts. Each chap data the authors obtained during the visits,
ter closes with a selected bibliography, the necessarily hasty, that they made to many of number of entries ranging up to 225 titles for the mineral deposits of Brazil, Chile and Peru. the chapter on Chile. The entries are gener
The opening chapter of the volume gives ally accompanied by brief synoptic characteran outline of the geography, general geology izations. It is not always indicated that some and mineral resources of South America. It
Latin-American entries are merely translasketches also the history of the growth of the tions of papers that appeared originally in mineral industry, discusses the relation of French, German, American or other publimining to other industries, and outlines the cations. probable trend of the future development. One of the notable sections of the volume
is the account of the Bolivian tin veins. Professors Miller and Singewald were fortunate in finding fossil plants in the shales at Potosi, and as a result of this discovery were able to establish that the tin veins at Potosi were formed in Pliocene or Pleistocene time. This is a remarkable conclusion and shows that these wonderfully productive tin lodes are in a geological sense extremely youthful; in fact they are probably the most youthful economically valuable mineral deposits of first rank in the world. Professors Miller and Singewald extend this age determination to all the Bolivian tin veins and maintain that they are all of Pliocene age. This conclusion may or may not be true, for the veins of the different districts appear to be associated with igneous rocks of a wide range of texture: pegmatites, aplites, granite, granite porphyry, rhyolite porphyry, rhyolite and“ true quartz porphyry.” As a matter of fact, no thorough field study of the Bolivian tin veins as a whole has yet been made. The studies hitherto made have been mainly petrographic, by geologists who have not collected the specimens they studied. It is not to be expected that a very deep insight into the fundamental problems could be attained by that method. Even in such a relatively subordinate matter as the nomenclature of the igneous rocks the petrologist has felt it necessary to use such obsolescent, non-committal terms as quartz porphyry to describe some of the rocks to which certain Bolivian tin veins are genetically related. When field work becomes the main method of attack and the microscope is used as auxiliary—a powerful auxiliary it is truemore satisfactory results will be attained, and it is therefore a pleasure to learn that Professor Singewald is returning to Bolivia in order to take up a careful study of the tin veins in their broader geologic aspects.
Another district of special interest is Corocoro in Bolivia, which like the Lake Superior district is one of the world's two productive copper districts in which the chief ore mineral is native copper. Brazil holds the distinction of having in the Morro Velho mine the deepest mine in the world, the lowest workings
having attained a vertical depth of 6,128 feet. The ore on the lower levels averages nearly $13 a ton in gold and indicates an extraordinarily long vertical range of gold-ore deposition. Apparently not much is known about the geology of this remarkable ore body, however. There are many other interesting deposits described in the book, but it would lengthen this review unduly even briefly to call individual attention to them. The outstanding feature of the economic geology of the South American continent is its preeminence in the number of its geologically youthful primary ore deposits of the first order of magnitude.
Professors Miller and Singewald have placed all interested in the mineral resources of South America under a deep debt for the labor they have expended in marshalling the widely scattered information and for presenting it attractively in a condensed and easily usable form. They can be gratefully assured that they have filled a genuine want in the literature of economic geology.
ADOLPH KNOPF UNITED STATES GEOLOGICAL SURVEY
THE ECOLOGY OF NORTH AMERICAN
LYMNÆIDÆ In a recent paper in SCIENCE the following statement appears:
“ There are three groups of limnæas found in North America, the abysmal limnæas including Lymnæa (Acella) haldemani Binney, the moss limnæas including Lymnæa (Galba) truncatula Müll., humilis Say, and the marsh limnæas including Lymnæa stagnalis, L. columella," etc. This classification of our pond snails is so unusual and so far from representing the true ecological relations of this group, as well as of the allied groups Planorbis and Physa, that a few observations on the subject seem necessary.
As far as known there are no abysmal lymnæas or other fresh-water pulmonates in America, comparable to the true abysmal fauna of the deep lakes in Switzerland, where Lymnæa stagnalis occurs in Lake Geneva at a depth of 250 meters and Lymnæa abyssicola
1 SCIENCE, N. S., XLVIII., p. 578, 1918 .
in Lac Leman at depths of 25 to 250 meters.? groups of fresh-water mollusks especially the
environment is protected from the force of the The species cited as an example of abysmal waves and wind by barriers of one kind or lymnæas, Acella haldemani (Desh.) Binney, another. The water is shallow and there is is really a shallow-water, swamp-loving species, usually an abundance of vegetation, such as when adult, in 'the fall, living at or near Scirpus, Potamogeton, Castalia, Nymphæa, the surface attached to vegetation in water Typha and filamentous algæ which provide less than five feet deep. In summer (July) much of the food of these snails. Such species the young may be found in water not exceed- as Acella haldemani (Desh.) Binn., Pseudoing six feet deep, among such plants as succinea columella (Say), Bulimnea megasoma Potamogeton.
(Say), and Lymnæa stagnalis Linné are typThe present center of distribution of Amer- ical of such a habitat. ican lymnæas is the Canadian faunal region, 3. The marsh type, where the water is shalwhere upwards of 50 species and races live. low, seldom more than three or four feet deep, North and south and east and west of this and where there is an abundance of swamp area there is a more or less rapid decrease vegetation such as Typha, Pontederia, Decodon in number of species. It is in this area that and a few Nymphæa. The bottom is usually we find the greatest variation in the ecological of mud
of mud or accumulated vegetable débris. relations of the group. This is due in part to Such species as Galba palustris (Müll.), G. the effect on the topography made by the obrussa (Say), G. reflexa (Say), and G. elodes great ice sheet which swept over the territory (Say) are characteristic of this kind of a during the Pleistocene Period, and left upon habitat. its retreat the largest number of ponds and 4. The mud-flat type. This type of habitat small lakes known in any part of the world. may border a swamp, pond or river, where the As typical pond and lake animals, the lymnæas water is quiet and where an area of wet mud have reacted favorably to this profusion of is left just above the water line. Here small small bodies of water and a large and varied species of the subgenus Simpsonia are at home fauna has resulted. This is also true of other and we find such species as Galba parva
(Lea), G. dalli (Baker), G. umbilicata 2 Forel, Bull. Soc. Vaudoise des Sci. Nat., X., p. 217; XIII., p. 1 (1869, 1874).
(Adams), and some of the small varieties of 3 Internationale Revue der gesamten Hydro- G. obrussa (Say) living by thousands, simubiologie und Hydrographie, Band 7, Heft 2–3, pp. lating the marine Littorinas in their ecolog146–204, 1915.
ical relations. 4 Walker, Nautilus, IX., pp. 3–5, 1895.
5. The intermittent pool or stream. This is 5 For the life history and ecology of this species
a type of habitat found in all parts of the see Baker, Nautilus, XXX., pp. 135–138; Tech. Pub. No. 9, N. Y. State College of Forestry at 6 Baker, “Monograph Lymn. N. A.," pp. 52–67, Syracuse University, 1918.