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terial premiums intended to aid original work The New York Evening Post states that among teachers in secondary schools were Major von Donat, the author of the wellawarded in the department of mathematical known plan for the drainage and colonization sciences to Professor Ciani (£50), Professor of the Pontine Marshes, has placed before the Pirondini (£38), and Professor Chini (£20). Bavarian government a project for creating a Out of the funds available from the Carpi source of electric power sufficient to run all prize, a sum of £32 was awarded to Dr. P. the railways of the country. He would secure Enriques for a thesis on the changes brought this power by damming the River Isar beabout in absorbed chlorophyll by the action of tween Wallgau and Vorderritz, thus creating the liver, and the relation existing between a new lake, and connecting this with the the derivatives of chlorophyll produced in the Walchensee and the Kochelsee. He has organism and the genesis of the hematic pig- figured out that this would effect a saving of ments. In his address the vice-president, F. $10,000,000 a year. d'Ovidio, discussed in general terms the ques- CONSUL STEPHENS, of Plymouth, reports that tion · Art for Art's Sake,' dealing more par a new return has just been issued for the first ticularly with the influence exerted on na- time by the British government. It is the tional life and character by art and literature. counterpart of the alien immigration returns, The autumn course of lectures of the New

and deals with the number of passengers who York Botanical Garden will be delivered in

leave England for places out of Europe, disthe lecture hall of the museum, on Saturday

criminating between the British Empire and

foreign countries. It appears that in the afternoons, at 4:30 P.M., as follows:

month of July, 21,000 Britons emigrated, two October 7, 'Autumn Features of Native Trees

thirds being from England, 4,392 from Scotand Shrubs,' by Dr. N. L. Britton.

land, and 2,631 from Ireland. That is a reOctober 14, The Faculties of Plants,' by Dr. D. T. MacDougal.

duction of 1,664 as compared with the correOctober 21. “Botanical Explorations in Hayti: sponding month of last year. As regards the by Mr. Geo. V. Nash.

past seven months, British emigrants numOctober 28, “A Summer in the Desert,' by Pro bered about 151,000, an increase of 13,447. fessor Francis E. Lloyd.

England contributed 98,460, Scotland 24,116, November 4, 'The Sea-gardens of Tropical and Ireland 28,333. Of British and Scotch America,' by Dr. M. A. Howe.

emigrants, rather more than one half go to November 11 (subject to be announced), by Dr. British colonies, and Canada takes by far the W. A. Murrill.

greatest proportion of them. The Irish, howNovember 18, ‘Fossil Plants,' by Dr. Arthur

ever, prefer the United States, with the result Hollick. November 25, “Tropical Fruits,' by Professor

that the republic gets more British people H. H. Rusby.

than Canada. It is claimed that the English The director-in-chief and other members of

and Scotch are far more partial to the Domin

ion than to the United States, and sent 55,000 the staff will be pleased to receive members

emigrants there as against 2,000 Irish in the and their friends at the grounds in Bronx

7 months. South Africa holds the next place Park, every Saturday for which lectures are

in popularity, and has taken nearly 13,000 announced. Opportunity will be given for

Britons in the 7 months, while Australia atinspection of museums, laboratories, library,

tracted 6,325. The returns also show that herbaria, the public conservatories, the her

110,000 foreigners left the United Kingdom, baceous collection, the hemlock forest and

chiefly for the United States, in the past 7 parts of the arboretum site.

months. The bridge over the Zambesi River in Africa Consul Keul, of Stettin, writes explaining has been formally opened in the presence of the new regulations that have been issued for the visiting members of the British Association. admission of students to technical high schools Professor Darwin made the opening speech. in Prussia. He says: The students will be di

vided into three classes—the 'regular'attending students, students for lectures only, and lecture-visitors. As regular students, without any exception, such young men will be accepted who have acquired the knowledge necessary for being admitted into any university, said knowledge to have been acquired at a German Gymnasium,' a German Oberrealschule' (a high school in which sciences as well as art and languages are taught), a Bavarian 'industrial school,' or the Saxonian Polytechnical Academy of Chemnitz. As to foreigners, the ministry of ecclesiastical affairs and public education is to decide whether their scholastic erudition is sufficient to admit them. German subjects, other than Prussian, will be admitted under the same conditions as Prussian subjects. As students admitted to hear the lectures only (i. e., without privilege of being graduated by the board of examiners), young men will be admitted, not possessed of the education necessary for being admitted into a German university, but having acquired the schooling necessary for performing only one year's military service. The admission of such students is put into the hands of the rector of the technical high school. As lecture visitors such persons may be admitted to the lectures or demonstrations who are not eligible to either of the two classes just mentioned. The admission of lecture visitors will be granted by the rector, with the consent of the proper professor. There is particularly one new restriction in these regulations, viz., that all encouragements for foreigners are dropped. Setting aside the lecture visitors, only such foreigners will be admitted as are capable of complying with the German educational requirements or who are in possession of an equivalent foreign certificate of learning.

purposes of charity and benevolence, and for the advancement of knowledge, especially in aid of human suffering. This sum has been apportioned for various purposes in the form of capital to be vested in trustees, and to be known in each case as the 'Bawden Fund.' The largest allotment is £16,000 to complete the sum of £200,000 required to bring about the incorporation of the University College in the University of London.

GIRTON COLLEGE, Cambridge, has received £2,000 by the will of Miss Elizabeth A. Manning.

An imperial ukase has been issued at St. Petersburg, granting a liberal measure of autonomy to universities, pending the elaboration of permanent regulations. This is expected to ensure the opening of the universities and the resumption of the educational life of Russia, which has been at a stand still since February. The ukase places the election of rectors and deans of the universities, who have hitherto been appointed by the minister of education, in the hands of the university professors. The duty of seeing that academic life follows a normal and orderly course is entrusted by the ukase to professorial councils, to which has been confided jurisdiction over offences by students.

Dr. CHASE PALMER, for some years professor of chemistry at the Central University of Kentucky, has accepted the position of professor of chemistry in the State College at Lexington, Ky., Dr. J. II. Kastle, who occupied the latter position, having recently gone to Washington as chief of the division of chemistry in the Hygienic Laboratory of the Marine Hospital Service.

Dr. FRIEND E. CLARK, who has for two years been instructor in industrial chemistry in the Pennsylvania State College, has been appointed professor of chemistry in the Central University of Kentucky, at Danville.

Dr. J. BENDIXson has been elected professor of mathematics in the University of Stockholm.

Dr. Oskar BREFELD, professor of botany at Breslau, has retired owing to failing eyesight.

UNIVERSITY AND EDUCATIONAL NEWS.

ANNOUNCEMENT is made of an anonymous gift to the Lebanon Valley College, Annville, Pa., of a hall of science to cost $80,000. Work on the building is to begin at once.

Mr. E. G. BAWDEN, London, has entrusted Mr. Edgar Speyer with a sum in cash and securities of about £100,000 to be applied to

A WEEKLY JOURNAL DEVOTED TO THE ADVANCEMENT OF SCIENCE, PUBLISHING THE OFFICIAL NOTICES AND PROCEEDINGS OF THE AMERICAN ASSOCIATION

FOR THE ADVANCEMENT OF SCIENCE.

FRIDAY, SEPTEMBER 29, 1905.

THE PROGRESS OF PHYSICS IN THE

NINETEENTH CENTURY.
CONTENTS.

II.
The Progress of Physics in the Nineteenth
Century, II.: PROFESSOR CARL BARUS..... 385

DIFFRACTION.
Scientific Books :-

Though diffraction dates back to GriFieberger's Civil Engineering: PROFESSOR H. N. OGDEN. Duckworth's Jorphology

maldi (1665) and was well known to Newand Anthropology: T. D................. 397 ton (1704), the first correct though crude Scientific Journals and Articles ............ 399 interpretation of the phenomenon is due to Discussion and Correspondence :

Young (1802, 1804). Independently FresThe Letter K in Zoological Nomenclature: nel (1815) in his original work devised T. D. A. COCKERELL. Hammock,' 'Hommock' or · Hummock'?: ROLAND M. HAR

similar explanations, but later (1818, 1819, PER. Indian Bone Combs: The Rev. W. M. 1826) gave a more rational theory in terms BEAUCHAMP ........................... 399

of Huyghens's principle, which he was the Special Articles:

first to adequately interpret. Fresnel The Systematic Name of the Japanese Deer: DR. LEONHARD STEJNEGER. The Possibility

showed that all points of a wave front are of Absorption by Human Beings of Nitrogen concerned in producing diffraction, though from the Atmosphere: DR. AXEL EMIL GIB

the ultimate critical analysis was left to SON ...........

..... 402 Quotations:

Stokes (1849). Mr. J. B. Burke's Experiments; The Chi. In 1822 Fraunhofer published his recago Death Rate........ ........... 405

markable paper, in which, among other

marzobie na Current Notes on Meteorology:

inventions, he introduced the grating into The Monthly Weather Review; Islands for Purposes of Weather Forecasting; Meteor

science. Zone plates were studied by ology and other Sciences; A New Text-book Cornu (1875) and by Soret (1875). Rowof Meteorology; Notes: PROFESSOR R. DEC.

land's concave grating appeared in 1881. W ARD ................................. 407 Notes on Inorganic Chemistry:

Michelson's echelon spectrometer in 1899. Solutions in Liquid Ammonia: J. L. H.... 408 The theory of gratings and other diffracThe First International Congress of Anat tion phenomena was exhaustively treated omists .................................

.............. 409

40

by Schwerd (1837). Babinet established Vagnetic and Allied Observations during the Total Solar Eclipse : DR. L. A. BAUER..... 411

the principle bearing his name in 1837. 4 Yational Conference of Trustees of Ameri

Subsequent developments were in part concan Colleges and Universities ............ cerned with the improvement of Fresnel's The Harrey Society.

method of computation, in part with a Scientific Notes and News.......

413 more rigorous treatment of the theory of University and Educational News........... 416 diffraction. Stokes (1850, 1852) gave the

first account of the polarization accomMSS. intended for publication and books, etc., intended panying diffraction, and thereafter Rayfor review should be sent to the Editor of SCIENCE, Garri.

leigh (1871) and many others, including son-on-Hudson, N. Y.

412

413. nu

Kirchhoff (1882, 1883), profoundly modi- thin plates of aeolotropic media with polarfied the classic treatment. Airy (1834, ized light came from Fresnel (1821). 1838) and others elaborately examined the Airy (1833) elucidated a special case of diffraction due to a point source in view the gorgeously complicated interferences of its important bearing on the efficiency obtained with convergent pencils; Neuof optical instruments.

mann in 1834 gave the general theory. A unique development of diffraction is The forbidding equations resulting were the phenomenon of scattering propounded geometrically interpreted by Bertin (1861, by Rayleigh (1871) in his dynamics of the 1884), and Lommel (1883) and Neumann blue sky. This great theory which Ray- (1841) added a theory for stressed media, leigh has repeatedly improved (1881, et afterwards improved by Pockels (1889). seq.) has since superseded all other rele

The peculiarly undulatory character of vant explanations.

natural light owes its explanation largely

to Stokes (1852), and his views were veriPOLARIZATION.

fied by many physicists, notably by Fizeau

(1862) showing interferences for path difAn infinite variety of polarization phe

ferences of 50,000 wave-lengths and by nomena grew out of Bartholinus's (1670)

Michelson for much larger path differences. discovery. Sound beginnings of a theory

The occurrence of double refraction in were laid by Huyghens (“Traité,' 1690),

all non-regular crystals was recognized by whose wavelet principle and elementary

Haüy (1788) and studied by Brewster wave front have persisted as an invaluable

(1818). acquisition, to be generalized by Fresnel in

In 1821, largely by a feat of 1821.

intuition, Fresnel introduced his generalFresh foundations in this department of

ized elementary wave surface, and the coroptics were laid by Malus (1810) in his

rectness of his explanation has since been discovery of the cosine law and the further

substantiated by a host of observers. discovery of the polarization of reflected

Stokes (1862, et seq.) was unremittingly light. Later (1815) Brewster adduced the

active in pointing out the theoretical bearconditions of maximum polarization for ing of the results obtained. Hamilton this case.

(1832) supplied a remarkable criterion of In 1811 Arago announced the occurrence

the truth of Fresnel's theory deductively, of interferences in connection with paral- in the prediction of both types of conic lel plane-polarized light, phenomena which refraction. The phenomena were detected under the observations of Arago and Fres- experimentally by Lloyd (1833). nel (1816, 1819), Biot (1816), Brewster The domain of natural rotary polariza(1813, 1814, 1818) and others grew im- tion, discovered by Arago (1811) and enmensely in variety, and in the importance larged by Biot (1815), has recently been of their bearing on the undulatory theory. placed in close relation to non-symmetrical It is on the basis of these phenomena that chemical structure by LeBel (1874) and Fresnel in 1819 insisted on the transver- van't Hoff (1875), and a tentative molecusality of light waves, offering proof which lar. theory was advanced by Sohncke was subsequently made rigorous by Verdet (1876). (1850). Though a tentative explanation Boussinesy (1868) adapted Cauchy's was here again given by Young (1814), theory (1842) to these phenomena. Indethe first adequate theory of the behavior of pendent elastic theories were propounded

by MacCullagh (1837), Briot, Sarrau The vibrations are in the plane of polariza(1868); but there is naturally no difficulty tion. in accounting for rotary polarization by All the elastic theories essentially predict the electromagnetic theory of light, as was a longitudinal light wave. It was not until shown by Drude (1892).

Kelvin in 1889, 1890 proposed his remarkAmong investigational apparatus of able gyrostatic theory of light, in which great importance the Soleil (1846, 1847) force and displacement become torque and saccharimeter may be mentioned.

twist, that these objections to the elastic

theory were wholly removed. MacCullagh, THEORIES.

without recognizing their bearing, seems In conclusion, a brief summary may be actually to have anticipated Kelvin's equagiven of the chief mechanisms proposed to tion. account for the undulations of light. With the purpose of accounting for disFresnel suggested the first adequate optical persion, Cauchy in 1835 gave greater theory in 1821, which, though singularly breadth to his theory by postulating a correct in its bearing on reflection and sphere of action of ether particles comrefraction in the widest sense, was merely mensurate with wave-length, and in this tentative in construction. Cauchy (1829) direction he was followed by F. Neumann proposed a specifically elastic theory for (1841), Briot (1864), Rayleigh (1871) and the motion of relatively long waves of light others, treating an ether variously loaded in continuous media, based on a reasonable with material particles. Among theories hypothesis of molecular force, and deduced beginning with the phenomena observed, therefrom Fresnel's reflection and refrac- that of Boussinesq (1867, et seq.) has retion equations. Green (1838), ignoring ceived the most extensive development. molecular forces and proceeding in accord The difficult surface conditions met with ance with his own method in elastics, pub- when light passes from one medium to anlished a different theory, which did not, other, including such subjects as ellipticity, however, lead to Fresnel's equations. total reflection, etc., have been critically Kelvin (1888) found the conditions im- discussed, among others, by Neumann plied in Cauchy's theory compatible with (1835) and Rayleigh (1888); but the disstability if the ether were considered as crimination between the Fresnel and the bound by a rigid medium. The ether Neumann vector was not accomplished implied throughout is to have the same without misgiving before the advent of the elasticity everywhere, but to vary in den- work of Hertz. sity from medium to medium, and vibra- It appears, therefore, that the elastic tion to be normal to the plane of polariza- theories of light, if Kelvin's gyrostatic tion.

adynamic ether be admitted, have not been Neumann (1835), whose work has been wholly routed. Nevertheless, the great reconstructed by Kirchhoff (1876), and electromagnetic theory of light propounded JacCullagh (1837), with the counter- by Maxwell (1864, “Treatise,' 1873) has hypothesis of an ether of fixed density but been singularly apt not only in explaining varying in elasticity from medium to me all the phenomena reached by the older dium, also deduced Fresnel's equations, theories and in predicting entirely novel obtaining at the same time better surface results, but in harmoniously uniting as conditions in the case of æolotropic media. parts of a unique doctrine, both the electric

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