The London, Edinburgh and Dublin philosophical magazine and journal of science . e tables. For the voltage wave as in fig. 7 themaximum is greater than for the equivalent simple sine wave is also more peaked, and hence the duration of thevoltage above the average value is reduced. It seems likelythat the shortening of the time in which the induced voltageis above a given value may, within limits, neutralize the Phil. Mag. S. 6. Vol. 2S. No. 164. Aua. 1914. O 194 Messrs. Magnusson and Stevens on Visual effect of a higher maximum value, and that the effectiveinstead of maximum values sh
The London, Edinburgh and Dublin philosophical magazine and journal of science . e tables. For the voltage wave as in fig. 7 themaximum is greater than for the equivalent simple sine wave is also more peaked, and hence the duration of thevoltage above the average value is reduced. It seems likelythat the shortening of the time in which the induced voltageis above a given value may, within limits, neutralize the Phil. Mag. S. 6. Vol. 2S. No. 164. Aua. 1914. O 194 Messrs. Magnusson and Stevens on Visual effect of a higher maximum value, and that the effectiveinstead of maximum values should be used in making com-parisons of threshold stimuli. Since in computing H andH7 the constant -y/2 was used, the values in the tables aredirectly proportional to the effective flux values. Lines of Force cutting the Retina and Optic Nerve.—Analternating current produces an alternating field, and hencethe flux H moves radially toward the axis of the coil as thecurrent increases, and in the opposite direction when thecurrent decreases. Therefore, the flux appearing in any. area like oab in fig. 9, bounded by two radii ox and oy anda nerve, represented by the line a, 6, cuts across the nerve,a-b four times for each cycle. In order to show what part of the flux cuts the opticnerve, fig. 10 was drawn showing the relative size andposition of the coil, the skull, the optic pathways, and fieldof vision. In fig. 10 the coil is presented as circular. As amatter of fact the coil was elliptical, the major and minoraxes of which were 23*8 and 21*3 cms. respectively. Sincethe movements of the lines of force are at each point normalto the ellipse, no flux will cross the major and minor angles AOB and COD show the incidence of the linesof force upon the right and left retinas. It is evident thatmore lines of force cut the nasal halves of the retinae thanthe temporal halves. It is also apparent that the optic nerveslie almost parallel to the normal of the elliptic coil, and thatt
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectscience, bookyear1840
