can scarcely be conceived without assuming a force of repulsion instead of attraction between molecules of the liquid.

But he surely can not mean to question the existence of negative surface tension at a surface between a liquid and solid, for how other wise are we to explain the most familiar facts in capillarity. Is it not negative surface tension which causes the water to rise in a capillary tube, or against a glass wall, and causes a drop of oil to expand indefinitely over a glass plate? Is it not the greater negative surface tension in the oil-glass surface which causes the film to expand against the contractile force, or positive surface tension of the oil-air surface?

Nor does it appear to be necessary to suppose a repulsive force between molecules of the liquid in order to account for the existence of such a negative tension, for if the resultant force of attraction on a particle of liquid near the surface, due to all particles on both sides of the surface lying within the range of sensible molecular attraction, is directed away from the surface and towards the interior of the liquid, the particle will tend toward the interior and we shall have positive surface tension but if the resultant attraction is toward the surface there will be negative surface tension.

In case of an air-liquid surface the attraction of neighboring liquid particles upon a particle in the surface is so much greater than any opposing outward attraction by adjoining air molecules that the first condition holds and the surface tension is positive. While at a glass-oil surface a particle of liquid near the surface may be supposed to be more strongly attracted by the neighboring glass molecules than by the oil molecules in its vicinity, in which case the resultant attraction is toward the glass, the potential energy of a liquid particle is less at the surface than in the interior of the liquid, and the surface tension is negative.

When liquid comes against liquid the case is complicated by the mobility of particles on both sides of the boundary. It seems probable, however, taking an oil-water surface as an ex

ample, that if the resultant attraction on an oil molecule at the surface is directed across the boundary from the oil side toward the water, that a water molecule at the surface being in the same situation with respect to the surrounding molecules will be urged in the same direction. In other words, we can hardly imagine a particle of one sort in the surface as being drawn in one direction by the attraction of all the surrounding particles on both sides of the surface, while a similarly situated particle of the other sort would be drawn in the opposite direction.

We may assume then that at a surface between two liquids, particles on one side are urged away from the surface, while those on the other side are urged toward it. That is, there are two influences, one tending to contract the surface and the other to expand it. If the first is predominant there is positive surface tension, this is the ordinary case where diffusion does not take place, as with water-oil or water-mercury.

If the second is predominant the surface tends to expand indefinitely, and the limit would seem to be reached only when one liquid is uniformly diffused throughout the other. In this case diffusion is to be expected also from the consideration that if particles in the one liquid are drawn so powerfully towards the other as to force the expansion of the second liquid in opposition to its contractile tendency, it seems probable that they will be drawn actually into the second liquid and thus the integrity of the surface be destroyed. We conclude, therefore, that a positive surface tension is to be expected between all liquids that do not interdiffuse.

If the particles in a colloid solution are to be regarded as solid, we may expect to find cases where the surface tension is positive and other cases where it is negative. Where it is positive there will be a tendency to flocculate, for as two colloid particles come together liquid particles move out from between them into the interior of the liquid, and the capillary region surrounding the particles is thus decreased in volume, and the potential energy of the system is diminished. When, on the other

hand, the surface tension is negative at the surface of a colloid particle, there will be no flocculation, and the particles will not approach each other near enough to crowd the liquid out of the region of surface energy around either particle. This, of course, does not imply that there is any tendency in the latter case for the colloid particles to remain in equilibrium equally diffused throughout the liquid. ARTHUR L. KIMBALL

AMHERST COLLEGE

THE WHITE PINE BLISTER RUST; DOES THE FUNGUS WINTER ON THE CURRANT?

IN the work carried out in the Province of Ontario during the last two years on this disease, strong suspicions have been aroused that the fungus may in some cases pass the winter on the currants themselves. Several lines of evidence support these suspicions.

1. The commencement of the currant stage each spring here and there over large areas, without any apparent relation to the pines therein.

2. The similar yearly recurrence of the currant rust in one particular district ten miles by four miles in extent. In this area (a) the rust outbreaks do not bear any apparent relation to the pines; (b) the pines are very few in number; (c) many lots of these pines are small and their freedom from disease has been established; (d) the evidence from five lots of these young pines growing close to infected currants indicates that the rust was not introduced into this area until 1914, and that therefore the prevalent currant stage of 1915 and 1916 could not be due to pine blisters, which have not yet had time to mature.

3. The finding of six cases of the currant stage early in the year from one to two miles distant from any possible source of pine infection.

4. The occurrence of currant rust in 1916 on two adjacent plants in a large plantation. Early in the year these two only were rusted. The only four plants which were badly diseased here in 1915 included these two.

5. The occurrence of a rust outbreak on a plot of one hundred black currant plants

which were badly rusted in 1914, and which had been set out in a disease-free neighborhood in the spring of 1915 to test hibernation. A hypothesis is advanced which gives a reasonable explanation of the suspected hibernation. The rust often causes early defoliation of the currant plants, and this defoliation is followed by a secondary production of foliage, due to the development of winter buds. The general occurrence of the rust on these secondary leaves suggests that, allowing for the two weeks' incubation period, the infection must take place very early in their growth, and the question naturally follows: can such started buds be infected at such an early stage in their development that if winter conditions set in soon after, the buds are still capable of surviving? W. A. McCUBBIN

DIVISION OF BOTANY,

EXPERIMENTAL FARM SYSTEM,
DOMINION OF CANADA,

November, 1916

PAMPHLET COLLECTIONS

TO THE EDITOR OF SCIENCE: I note in SciENCE for November 24, an article by Tracy I. Storer from the University of California on "The Care of Pamphlet Collections" in which a type of cardboard case open at the back only and "not larger than 12 X 8 X 2 inches" is recommended for this purpose. Permit me to state that such cases differing only in sizemine are 11 X 7 X 3 inches-have been in use in my department since 1904. Several other departments in the university had such cases made after my design and they have been in rather general use here since. I do not remember whether the idea is original with me or not. These cases are arranged alphabetically by authors and the card index is by subject with the catch word first on the card. CHAS. B. MORREY

DEPARTMENT OF BACTERIOLOGY,
OHIO STATE UNIVERSITY

INDUSTRIAL LABORATORIES AND SCIENTIFIC INFORMATION

TO THE EDITOR OF SCIENCE: The undersigned committee on engineering of the General Committee on Research, of the American Associa

tion for the Advancement of Science, feel that it is timely to issue the following appeal to the industrial research laboratories of the country.

In the course of work done in the numerous industrial laboratories of America, many physical and commercial constants and data of great scientific interest and value are doubtless arrived at, which may, for a certain period of time, constitute an asset of considerable commercial value to the particular corporations in question. During this period, every one recognizes the proprietary right of the industrial laboratories to the retention of

this information.

A time frequently arrives, however, when such scientific information loses its commercial value (often by being duplicated in other laboratories), and just at this point we wish to impress upon the industries their obligation

to enrich scientific literature with such facts and data, which might otherwise be lost or forgotten.

Some of our industries have been reproached with the suspicion of acting as sponges, in that they absorb an immense amount of useful information from scientific literature without giving any return in kind. This suspicion would be entirely removed if, from time to time, scientific information which has ceased to be of commercial value were contributed by them to its appropriate channel and thus became available to all scientific workers throughout the world.

If any doubt exists as to the appropriate channel for the publication of such scientific data and communications, the general secretary of the American Association for the Advancement of Science, Dr. J. McKeen Cattell, Garrison-on-Hudson, New York, will be glad to act as intermediary and to forward such communications to the proper scientific body.

CAMBRIDGE, MASS., January 18, 1917

A. E. KENNELLY,
J. W. RICHARDS,
A. SAUVEUR,
A. N. TALBOT,
C. C. THOMAS

SCIENTIFIC BOOKS

Lectures on Ten British Mathematicians of the Nineteenth Century. By ALEXANDER MACFARLANE. No. 17 of the Mathematical Monographs, edited by Mansfield Merriman and Robert S. Woodward. John Wiley and Sons, New York, 1916.

This posthumous publication contains most interesting biographies of ten of the leading mathematicians of the nineteenth century in Great Britain, namely, of George Peacock, Augustus De Morgan, Sir William Rowan Hamilton, George Boole, Arthur Cayley, William Kingdon Clifford, Henry John Stephen Smith, James Joseph Sylvester, Thomas Penyngton Kirkman, Isaac Todhunter.

These sketches are a part of the lectures given by Dr. Macfarlane at Lehigh University during the years 1901-04. "In a future volume it is hoped to issue lectures on ten mathematicians whose main work was in physics and astronomy." The author's personal acquaintance with some of these men, and with intimate friends of them, enabled him to add personal touches which will be relished by the reader. Particularly gratifying are the details about Boole and Kirkman, concerning whom little had previously appeared in print. The future historian of mathematics during the nineteenth century will find the booklet full of interesting material. The lecturer's aim was evidently to set forth the personalities whose scientific achievements were already known to the listener. Hence the scientific researches of these men are not described, but merely mentioned.

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form. Carelessness in the proof-reading is noticeable. Frequently letters are dropped out of words, their unceremonious departure being accentuated by the blank spaces left behind. The description of Newton's fluxional notation on page 9 is rendered unintelligible to one not already familiar with it by the omission in several instances of the necessary dots. The spelling on page 35 of Clairaut as "Clairault" is unusual, to say the least. The statement, page 120, that it was in 1872 that a deputy professor was appointed at Oxford to carry on the work relinquished by Sylvester is evidently wrong, since Sylvester was appointed to the Oxford position in 1883. It is too bad that the editors of this book allowed the repetition of the erroneous statement that the name of Sylvester's father was Abraham Joseph Sylvester. As recently stated by several writers, the name Sylvester" did not belong to the father, but was assumed by an elder brother of the mathematician who had come to the United States, and later by the mathematician himself. The father's name was Abraham Joseph. The editors might also have corrected a mistake thus far almost universal, to the effect that Peaucellier was the first to devise an instrument for drawing a perfect straight line. It is a matter of great historical interest that a Frenchman by the name of Sarrut achieved this several years before Peaucellier, and in a manner quite different. An account of it will be found in the Comptes Rendus, Vol. 36, 1853, page 1036. Attention to Sarrut was called in 1905 by G. T. Bennett of Emmanuel College, Cambridge, in an article published in the Philosophical Transactions, 6th S., Vol. 9, page 803. Bennett gives interesting historical details, and also noteworthy developments of his own. FLORIAN CAJORI

COLORADO COLLEGE,

COLORADO SPRINGS, COLO.

The Whalebone Whales of New England. By GLOVER M. ALLEN. Memoirs of the Boston Society of Natural History, Vol. 8, No. 2, pp. 107-322, pls. 8-15, text-figs. 1-12. September, 1916.

Dr. Glover M. Allen's "The Whalebone Whales of New England" treats of the three genera and six species of baleen whales "inhabiting the waters off the New England coast," with special reference to their habits, manner of occurrence, economic importance and technical history. Two "keys" are given for their identification, one for stranded specimens that can be approached and examined, the other for identification in life, based on their characteristic actions, the presence or absence of a fin on the back, and the size and form of the spout.

Following a few introductory pages of comment on the classification of whales in general and of the New England species in particular, the author deals at length with each of the living species, with a brief account of the single fossil species, long known from a few vertebræ and other fragmentary remains found at Gay Head, Marthas Vineyard. The North Atlantic right whale (Eubalona glacialis) is of special interest historically on account of its having been the basis of the early New England whale fishery. This phase of the subject is presented in considerable detail (pp. 131-172), with many quaint extracts from early colonial records.

The species treated are: (1) North Atlantic right whale (Eubalana glacialis), (2) common finback (Balaenoptera physalus), (3) pollack whale (B. borealis), (4) blue whale (B. musculus), (5) little piked whale (B. acuto-rostratus), (6) Atlantic humpback (Megaptera nodosa). A methodical and concise account of each is given under appropriate subheadings, beginning with "history and nomenclature," followed by descriptions of their external and osteological characters, habits and food, seasons of occurrence, pursuit and economic products, enemies and parasites. Five of the species are illustrated by full-page plates of the external form, drawn to scale from careful measurements. Outline drawings of skulls are given in another plate, several photographic views of whales in another, and vertebræ and other fossil remains from the Miocene deposits of Gay Head in another. The monograph thus forms a valuable addi

tion to the literature of the subject, constituting, as it does, the first attempt to treat comprehensively this important part of the marine mammal fauna of New England, and is a highly satisfactory summation of present knowledge of the subject. A bibliography of six pages (about 100 titles) gives references to the technical literature cited in the text, in addition to which are numerous footnote and other references in the text to historical records relating to the distribution and occurrence of the species in New England waters, from early colonial times to the present.

J. A. ALLEN AMERICAN MUSEUM OF NATURAL HISTORY

PROCEEDINGS OF THE NATIONAL

ACADEMY OF SCIENCES

THE eleventh number of Volume 2 of the Proceedings of the National Academy of Sciences contains the following articles:

Path Differences within which Spectrum Interferences are Observable: Carl Barus, Department of Physics, Brown University. The method of observing interferences in the zeroth, first, second, third, and even fourth order, successively, without essential change of the parts of the apparatus is noteworthy. The present experiments furnish a striking example of the uniform breadth of the strip of spectrum carrying the fringes, quite apart from the dispersion of the spectrum.

Non-Reversed Spectra of Restricted Coincidence: Carl Barus, Department of Physics, Brown University. The method, apart from any practical outcome, is worth pursuing because of the data it will furnish of the width of the strip of spectrum carrying interference fringes under any given conditions.

strength of boric acid. These buffers regulate the reaction of sea water in a manner similar to the way in which bicarbonates and phosphates regulate the reaction of blood.

An Apparent Correspondence between the Chemistry of Igneous Magmas and of Organic Metabolism: Henry S. Washington, Geophysical Laboratory, Carnegie Institution of Washington. The object is to call attention to what appears to be a congruous relation of two pairs of elements in the organic world; it would appear that iron and sodium are necessary for animal metabolism, while magnesium and potassium are essential to vegetable metabolism.

The Oaks of America: William Trelease, Department of Botany, University of Illinois. A summary of a manuscript now prepared for submission to the academy for publication as one of its scientific memoirs. 354 species of oaks, of which about one half are new, are recognized. The relations to fossil oaks are pointed out.

A Set of Independent Postulates for Cyclic Order: Edward V. Huntington, Department of Mathematics, Harvard University. Five postulates are given for cyclic order.

A New Method of Studying Ideational and Allied Forms of Behavior in Man and Other Animals: Robert M. Yerkes, Psychological Laboratory, Harvard University. A descrip

tion of the author's method of multiple choices for the deduction of reactive tendencies and the study of their rôle in the attempted solution of certain types of problem. The method involves the presentation to the subject of a problem or series of problems whose rapid and complete solution depends upon ideational processes.

Electrical Conduction in Dilute Amalgams: Gilbert N. Lewis and Thomas B. Hine, Department of Chemistry, University of California. The resistance of amalgams of lithium, sodium and potassium is studied at constant pressure and shows extraordinary differences; the resistances at constant average atomic volume are also calculated and found to differ materially from those at constant pressure.