September 27, 1895.] 



SCIENCE. 



419 



tion was that no adaptation whatever exists 

 in the fovea (retinal point of clearest vision). 

 It is consequently blind to lights that are yet 

 easily seen by adjacent regions, and all colors 

 are seen by it as colors if seen at all. The re- 

 lations of these observations to color theories 

 the author has reserved for succeeding papers. 

 It is to be regretted that M. Parinaud has not 

 coordinated his work with that of von Bezold, 

 Hillebrand, Konig, Christine Ladd Franklin 

 and others, who have, one or another of them, 

 made all or nearly all of these observations be- 

 fore. E. C. Sanfoed. 



SCIENTIFIC JONBNALS. 

 THE PHYSICAL REVIEW, VOL. III., NO. 2, SEP- 

 TEMBER-OCTOBER. 



A Study of the Polarization of the Light 

 Emitted by Incandescent Solid and Liquid Sur- 

 faces : By R. A. Millikan. In spite of its 

 important bearing upon the whole theory of 

 radiation, the subject of polarization by emis- 

 sion appears to have been heretofore almost 

 wholly neglected. As is pointed out by Dr. 

 Millikan in the brief historical introduction to 

 his own observations, no quantitative study of 

 this subject has yet been made ; and even quali- 

 tative observations appear to be rare. Having 

 a clear field. Dr. Millikan has therefore under- 

 taken a thorough investigation of the phenome- 

 non. Experiments were first made in order to 

 make certain that the effect is not due to refrac- 

 tion through the heated air at the incandescent 

 surface. For this purpose a piece of platinum 

 foil was brought to incandescence in vacuo. The 

 light emitted showed the same degree of X'olari- 

 zation as was observed when air was present. 

 It thus appears that the polarization occurs 

 within the radiating body. 



Qualitative observations were next made upon 

 a great variety of, substances, in order to deter- 

 mine to what extent the phenomenon depends 

 upon the nature of the surface. In all cases 

 it was found that the polarization was in a 

 plane perpendicular to the plane of emergence. 

 Most metals showed a strong polarization, es- 

 pecially at grazing emergence ; and provided 

 the surfaces were not altered by oxidation, the 

 behavior of molten metals was similar to that of 



solids. Non-metallic substances, such as glass 

 and porcelain, showed the eflfect in less degree 

 than did the metals. The transparency or non- 

 transparency of the material appears to have 

 little influence upon the amount of polarization 

 observed. For quantitative observations the 

 author used the polariscope of Cornu, an instru- 

 ment quite simple in construction and yet cap- 

 able of. considerable accui-acy. The present 

 paper contains a discussion of the sensitiveness 

 of the instrument, together with a few observa- 

 tions made with it; but the discussion of most 

 of the quantitative work is postponed until the 

 second half of the paper, which will appear in 

 the November number. 



Alternating Currents when the Electromotive 

 Force is of a Zigzag Wave Type. By E. C. RlM- 

 INGTON. Of course no dynamo will give an B. 

 M. F. curve of the zigzag form. Nevertheless 

 when certain harmonics are present in unusual 

 prominence this shape of curve is sometimes 

 approached. Mr. Rimington has investigated 

 the relation between current and electromotive 

 force in an inductive circuit for the ideal case, 

 in order to be able to predict roughly what will 

 occur in practice. The mathematical methods 

 used are novel, and results are obtained in such 

 form as to be readily available for calculation. 

 Perhaps what will most strongly appeal to the 

 reader are the diagrams giving the curves of- 

 electromotive force current for certain assumed 

 values of the resistance and inductance. Dia- 

 grams are' also given for the case of an E. M. 

 F. curve of the rectangular type. 



On Ternary Mixtures. By W. D. Bancroft. 

 This is a continuation of an article begun in the 

 July number, which has already been noticed 

 in Science. Furttier abstract will be postponed 

 until the article is completed. 



On a Simple Method of Photographically Reg- 

 istering the Infra-Red Energy Spectrum : By 

 Knut Angstrom. In this paper are described 

 two forms of apparatus for obtaining auto- 

 graphic bolometer records, the results achieved 

 being similar to those obtained by Langley in 

 his recent work on the infra-red solar spectrum. 

 Dr. Angstrom makes no attempt to improve 

 upon the elaborate apparatus of Langley, the 

 wonderful results of which he does not hope to 

 equal. But, as he very truly remarks, " such 



