has not wished for a standard series of symbols. The question is not a new one; it was considered by a committee of the American Association for the Advancement of Science many years ago, but its efforts were shattered in the attempt at international cooperation. Such cooperation is very desirable, but if it is not available that is no reason why America should deny herself the benefits of coordination which she, with her scientific resources, may devise. Every monograph, every textbook that is written adds to the confusion of symbols, for there are no standard tables to guide one. It seems to me not only possible, but practicable that a list of symbols could be compiled under various headings-mathematical, astronomical (with subdivisions), physical (with subdivisions), geophysical, electrical, etc. The various headings would be necessary because the same symbol is frequently used under different headings, and, of course, with different meaning. Whether we write g for terrestrial acceleration or a is fundamentally quite immaterial, so it is whether we write L, or 4, or λ for latitude, but it is not immaterial for the person who reads it. He will probably wonder why the writer doesn't use such and such symbol. We want uniformity, uniformity to as great an extent as possible. Personal preferences should be waived and sunk in the greater scheme of uniformity. There are already many constants, many expressions, many concepts that await being labeled for common recognition. Who is to undertake this work, who is to do the labeling? I can see, or rather I can hear rumbling-"I'm not going to be bound by any such tables." Quite so, they would have no authority whatever. However the dictates of common sense would be their propelling force and I think the vast majority of American scientific writers would avail themselves of their usefulness. Anything that promotes readiness of understanding and ease of reading mathematical expressions and equations should be encouraged. In order to give definiteness to my ideas, which I hope will arouse discussion, I would suggest that the tables of symbols spoken of be prepared by the Carnegie Institution of Washington. It is work that so eminently falls within its scope, and it is so well equipped with material and other resources, that one can look forward with confidence to a wellmatured publication. Should the work be undertaken by the Carnegie Institution nothing would further the general adoption of the symbols promulgated more than the wide distribution of the publication and that could be profitably effected by sending to every scientist-to every man in "American Men of Science "gratis a copy of the Carnegie publication. My closing word: Don't let details smother uniformity. Make a start. OTTO KLOTZ DOMINION OBSERVATORY, OTTAWA, August 4, 1917 BACTERIAL LEAF SPOT OF TOBACCO A BACTERIAL leaf spot of tobacco has been found to occur within certain sections of North Carolina. This disease, because of the rapidity with which it spreads, has appropriately been given the name "wild fire." It first manifests itself in seriously destructive form at the time of transplanting, so that in some fields it has been necessary to replace the seedlings by a second and a third transplanting. Plants in the seed beds from which these seedlings were taken have been found to be diseased, indicating that the malady was introduced from the seed beds. The disease first appears as circular yellow spots about 1 cm. in diameter. A minute brown area indicates the center of the spot. Within a few days the brown area will have enlarged to 2 or 3 cm. in diameter with a translucent border and surrounded by a wide chlorotic halo. When the spots are numerous they fuse, forming large brown irregular areas which in severe cases involve most of the leaf tissues. Isolation and inoculation work has shown that the disease is due to a grayish white bacterial organism which is heretofore undescribed. This organism is rod shaped, about three times as long as wide, and actively motile by a single polar flagellum. It is therefore referable to Cohn's Bacterium as amended by Smith and is given the name Bacterium tabacum. The detailed account of the cultural studies and inoculation experiments which have been made, and of the distribution and dissemination studies which are in progress, is reserved for subsequent publication. F. A. WOLF, A. C. FOSTER NORTH CAROLINA EXPERIMENT STATION PLANT DISEASES IN CANADA TO THE EDITOR OF SCIENCE: Two plant diseases have recently been observed in the Dominion of Canada which have not been recorded before, viz., Dothichiza Populea Sacc. et Briard, on Lombardy poplar, St. Andrews, N. B., and Colletotrichum cereale Manns, on spring wheat, Charlottetown, P. E. I. A third disease affecting seed pods of turnips grown for seed in P. E. I. caused by Leptosphaeria Napi (Fuckel.) Sacc., of which the conidial form Sporidesmium exitiosum was found, does not appear to have been recorded as causing trouble on the continent of America. It is well known in Europe, where it is disastrous to seed turnip cultures. H. T. Güssow COMMON PLANT NAMES TO THE EDITOR OF SCIENCE: May I draw attention to a point in the discussion on popular names of plants, which M. A. Bigelow, in SCIENCE of July 6, seems to ignore; that is, the great literary value of a good common name and the danger that such names may be lost through being ignored by teachers. Of course children can learn any name-they memorize far more easily than grown people -but do not let us give them scientific names to learn as a part of nature study, unless they are going in for botany as a science. Scientific names are usually clumsy and pedantic, almost always lacking in character, and often can not be gracefully absorbed into the Engglish language. The names which Professor Bigelow cites as being both popular and scientific are sufficiently euphonious, but are almost all those of garden plants, which may be allowed to bear florists' names. The few wild flowers he mentions all have good common names, which apparently he is willing to discard. Primrose is an older name than Primula, I fancy, and for the matter of that, surely rose, lily and violet antedate the systematists! Clematis and Trillium are pretty enough, but virgin's bower and wake-robin are names to make a poet sing for joy. Most eastern wild flowers have fairly good names and even in the west -a young civilization is apt to be content with variations of "bells" and ". roses "—they have some fine names, such as our Lord's candle" (Yucca Whipplei), "sweet-afterdeath" (Achlys triphylla) and "flaming sword" (Fouquiera splendens). Such names as these enrich our language and should be preserved at all costs. Shall we encourage children to gather nosegays of Blepharipappus, Mesembryanthemum and Malacothrix? Heaven forbid! Only give them time and children will evolve good names for all conspicuous wild flowers, if we do not thwart them by teaching the scientific ones unnecessarily. Cat's breeches, named by Utah children, may not be elegant, but it is quaintly appropriate and is certainly better for everyday use than Hydrophyllum capitatum. Let us go slowly in these matters and so long as men like Dr. Jepson are continually on the lookout for good common names we need not despair. MARGARET ARMSTRONG A SIMPLE EXPLANATION IN SCIENCE, August 31, 1917, page 212, Professor C. A. Mooers writes as follows: The writer has assumed that Dr. Hopkins could give a simple explanation for his conflicting estimates, as given in SCIENCE, November 3, 1916, p. 652, and in SCIENCE, March 2, 1917, p. 214. In the former article he says: "For each dollar invested rock phosphate paid back $2.29,'' but in the latter article he says, with regard to the same data, "Easy computations show profits per dollar invested of . . . $1.29 from phosphate rock." The "simple explanation" is that these are not conflicting statements. Each dollar invested in raw rock phosphate paid back $2.29; and, when the dollar invested is subtracted from this amount, the profit is found to be $1.29. In this article Professor Mooers bases his opinions in part upon "observations and "hay data. . . not given in Bulletin 90," states that in his conclusions he "6 was governed chiefly by a consideration of the soil conditions and the results of the individual series "; and he criticizes my use of a summary table which he prepared and which he also used in his bulletin1 and in his former SCIENCE article.2 His present opinion is that this summary table is not fairly representative of the results secured, and I must bear his criticism for having used it. UNIVERSITY OF ILLINOIS CYRIL G. HOPKINS QUOTATIONS COLUMBIA UNIVERSITY AND PROFESSOR CATTELL IT is contrary to the academic traditions of six hundred years to dismiss a university professor on account of his opinions expressed in a proper way to experts in the subject. It is illegal to dismiss a professor in the middle of the academic year on false and libelous charges, without payment for the year and without the pension which he had earned by twenty-six years of service. I am opposed to war and to this war, but I have undertaken no agitation against the government nor against its conduct of the war. I have written nothing against the draft law or against sending armies to Europe, although I regard both measures as subversive of the national welfare. It is because I care for my country that I deplore its entry into a war of aggression and the government's policy of strangling democratic principles at home. For the same reason I have in the journals which I edit done 1 Bulletin No. 90, Tennessee Agricultural Experiment Station. 2 SCIENCE, January 5, 1917. what I could to promote national efficiency. I am a member of the Psychology Committee of the National Research Council and spent a large part of last week drawing up for the War Department plans for the scientific selection of aviators. In August, 1914, when President Wilson was telling us to be neutral in thought as well as in speech and in act, and Mr. Roosevelt and Dr. Nicholas Murray Butler were "pussyfooting," I wrote in one of the journals that I edit: The official German justification of the mad and wanton European war is that it is in defense of the Teutonic culture and people against the semi-Asiatic and barbaric Slav hordes. The verdict of history will probably be that it was a war of calculation for caste and national aggrandizement, and a war of miscalculation. The German emperor and his bureaucratic military entourage probably held that the time was ripe for an extension of German influence in the Balkans and towards Asia Minor with an increase of its African possessions at the expense of France. But it is not clear why, if the serpent was prepared to use its fangs, it did not show its alleged wisdom. . . . We may look for a second Napoleon the little rather than for a second Napoleon the great. In June, 1917, I began a letter to the New York Evening Post with the words: An emperor, driven by the militaristic and capitalistic classes of his people and "by God demented,'' must accept responsibility for the great crime. The letter that I wrote on August 23 to members of the Congress, on account of which I have been dismissed from the chair of psychology at Columbia University, asked support for a measure then before the Senate and the House to prohibit sending conscripts "to fight in Europe against their will." There is no law requiring or permitting the President to send "conscientious objectors" to fight in Europe. To do this would be contrary to the intent of the constitution and to the uniform policy of the nation. It would provide a less efficient army and might cause disorder and possible revolution at home. Surely this should not be done without careful consideration by the Congress after efforts to learn the will of the people. I have only exercised the constitutional right and fulfilled the duty of a citizen in petitioning the government to enact legislation which I believe to be in the interest of the nation. For this I am dismissed from the division of philosophy, psychology and anthropology, which I have made the strongest in the world. Professors in every university are terrorized, so that they dare not exert their influence for peace and good will. The people of all the European nations long for peace, but are kept at war by the kleptocratic classes. In spite of the institutions and the instincts which we have inherited from a barbarous past, I believe that our people have no heart for this war into which they have been driven. But even if the nation should become a mob mad for war, it is none the less the business of each of us to do what he can for righteousness as he sees it. If that is forbid by force, then indeed we need a new national anthem, such as Shelley once wrote for England: God prosper, speed and save, Pave with swift victory The steps of Liberty, -J. MCKEEN CATTELL in a statement SCIENTIFIC BOOKS Chemistry in the Service of Man. By ALEXANDER FINDLAY, M.A., D.Sc., F.I.C. Longmans, Green & Co., London, New York. 1916. Pp. xiv +255. Price $1.60. This book is the outgrowth of a series of lectures the Thomson Lectures-delivered by the author before the United Free Church College at Aberdeen, near the close of the year 1915. It represents the attempt to lay before a group of college men, who made no claim to chemical knowledge, some account of what chemistry has accomplished for the well-being and uplift of mankind, and also some glimpse of the relation of chemistry to the war. The book is in England especially timely, from the fact that among the educated classes, as well as among the business men and industrialists, an appreciation of chemistry has been sadly wanting. The case is somewhat different in this country, since for many years chemistry in a large share of our colleges and universities has been either a required study or a widely chosen elective, and has become a part of the curriculum of most of our high schools. Probably on account of this our manufacturers have shown far less reluctance than those of England to abandon their "rule of thumb" methods. Such books as the one before us are always timely, never more so than to-day, provided the author is a master of his subject and at the same time capable of expressing his thought in language that can be understood by the man with little or no previous knowledge of chemistry. Dr. Findlay well fulfils both of these conditions. His work in physical chemistry is well known; his success in opening up difficult fields in chemistry to the comprehension of the ordinary chemist is evidenced by the clearness of his "Phase rule and its applications" and his "Physical chemistry and its applications in medical and biological science." This latter book, by the way, should be read by every medical student. The aim of "Chemistry in the service of man " is best set forth in a sentence in the introductory lecture: "In attempting a brief and necessarily incomplete survey of chemistry in the service of man, I shall endeavor not merely to recount some of the manifold ways in which chemistry has revolutionized life and has contributed, on the material side, to a civilized existence; but I shall try, also, to indicate, if I can not do more, some of the principles which underlie chemical change, and some part of the contribution which chemistry has made to our knowledge of the constitution of matter." The latter is rather an ambitious program for a popular book, intended for readers without previous knowledge of chemistry. The chapters entitled "Velocity of reaction and catalysis," "Electricity and chemistry," "The colloidal state," and "Molecular structure" would hardly seem fitted for popular perusal, and yet so clearly are the fundamental principles treated that any intelligent man, or high-school scholar, for that matter, would hardly fail to be understandingly interested in the application of these principles to important facts of every-day life. The consideration of catalysis leads to its application in the manufacture of sulfuric acid and the hardening of fats, and to some of the facts concerned with digestion; in connection with electricity are discussed the refining of metals, the manufacture of chlorin and caustic soda, and many electric-furnace products; the colloidal state is illustrated by photographic plates, the sedimentation of rivers, plasticity of clay, dyeing and water and sewage purification. Perhaps the most interesting chapter is that concerned with the fixation of nitrogen, particularly applicable to the demand, both for munitions and for fertilizers, at the present time. Other chapters are "Combustion, and the production of fire," "The chemistry of illuminants," "Energy, fuel and explosives," "Cellulose and cellulose products," "Glass, soda, soap," and "Synthetic chemistry." All are exceedingly readable, and are to be recommended, not only to the man who desires to get a glimpse of what modern chemistry is doing for the comfort and needs of life, but quite as well to the first-year student of chemistry, in school or in college, who has far too often come to regard the study as a mass of unconnected facts and abstruse theories, mingled with a mess of dirty test tubes and beakers. In this book one gains a glimpse of the beauty of it all, if indeed one has any comprehension of beauty. One word remains to be said. Many of us were trained in our earlier years to believe that for the past half century all chemistry was "made in Germany," and in this there was far more of truth than of fiction. And yet it is hardly an exaggeration to say that in England, America and France more progress has been made in the past thirty-six months than had been made in Germany in the previous thirty-six years. Perhaps the same has been true of Germany; our information regarding this is meager. As never before, chemistry is "coming to her own," and hence the timeliness of Dr. Findlay's "Chemistry in the service of man.' JAS. LEWIS HOWE WASHINGTON AND LEE UNIVERSITY Ulugh Beg's Catalogue of Stars. By EDWARD BALL KNOBEL. Carnegie Institution of Washington, Publication No. 250. 1917. Pp. 109. Mr. Knobel's compilation of Ulugh Beg's Catalogue forms a fitting sequel to Ptolemy's Catalogue of Stars, also edited by Mr. Knobel in conjunction with Dr. C. H. F. Peters. Ulugh Beg, born in 1394, succeeded his father as ruler of Persia in 1447. Two years later he was killed by his son. He devoted much of his time to astronomy, was the founder of an observatory at Samarkand, which is located in the southern part of Russian Turkestan, and in the year 1437 published a catalogue of stars. Such catalogues furnish at best only rough determinations of stellar positions because of a number of causes. To add to the insecurity of the positions, it is not always certain whether all the stars of such a catalogue have been directly observed by the author, or whether, for the sake of completeness he has added star positions determined by predecessors, and reduced to the epoch of his own catalogue in a manner unrecorded. Added to this is the doubt whether the manuscripts available contain a true record of the original catalogue. While it is eminently worth while to pre serve such a catalogue, if only for historical purposes, great care should be taken not to place too great dependence upon its star positions. Mr. Knobel has apparently made a thorough investigation of the subject. In addition to the catalogue proper he has included a comparison of Ulugh Beg's star positions with positions reduced from Piazzi's catalogue, with the exception of 300 stars whose positions were reduced from the catalogues of Danckwortt and Neugebauer. Following the comparisons he has collated the manuscripts which were examined, and closes the volume with a vocabulary of Persian words prepared |