. Journal. en were washed underrunning water for one hour. The density was determined by the Martens polarisa-tion photometer, and calculated according to the formulagiven by Martens and Micheli(2). Dr = 2(log tana—log tan S) Dr means the relative density of the developed plate ; a, the angle of rotation of Nicola for the part of the plate the relative density of which is to be measured, when both semi-circles of the field of the photometer appear equally light; S, the angle of rotation of Nicols for the unexposed but developed part of the same plate. Tables I. and II. show these results graph
. Journal. en were washed underrunning water for one hour. The density was determined by the Martens polarisa-tion photometer, and calculated according to the formulagiven by Martens and Micheli(2). Dr = 2(log tana—log tan S) Dr means the relative density of the developed plate ; a, the angle of rotation of Nicola for the part of the plate the relative density of which is to be measured, when both semi-circles of the field of the photometer appear equally light; S, the angle of rotation of Nicols for the unexposed but developed part of the same plate. Tables I. and II. show these results graphically. The curves are constructed in such a way that the ordinates represent the relative density, and the abscissae, the logarithms of (i X t), , the logarithms of the product of the intensity of light in and the length of the time of exposure in seconds. 10 seconds 20 »» 40 »» 80 *» 160 ,, 320 ,, .w JOURNAL OF THE SOCIETY OF CHEMICAL INDUSTRY. [June IS, ltug Table 18° C. Tabic I. *M»)»«!,»,»>»». »ss1»«l»H« QvMn^vivo**^ «-SB*«l«M!«l»Nlin»««l«». « st. Table ! Oialntt 18J C. T ] — V it ll > n r >—0 k J-7 T — — V-v —? =*= s-^ 1 1 I 1 « _ N \ ?/20 ^ i j \ / V i 8?7 ?>. / 1 --« / 1 / / ?2 y -» r • / •s * f S r^ * > s f ?s / - r* ??*3•2 ^ > ^?i r^ -« — - - -r » =w .fcffTi * > - ? i * * * , 1 i tk t * 0 -1 — • c I • > * ? ? 6 * » « > c >< ? h . i 1 t » 1 . v 1 « h i » 1 ? • v i << ? l « V «. C 1005.] i DON SECTION. 585 lin results how that: — di tisity of a photographic plate for an exposure,,. game length of time and when developed withsame kind of developer increases according to the i the time of dovelo] int. I \\ 11. 11 the time of development is short, there isreal difference in the density h\ changing the effectualmm ix t- i.) By increasing the time
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
