Chemistry and Physics. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Constitution of Solutions.— Kates has applied the 



taining two or more colored substances does not correspond in all 



cases to the sum of the separate spectra. Whether this lias a 



tra, Krfiss used ab>orptiou cells with parallel glass side*, the 

 width of the cell being exaetlv 5""" and the sides being - ,: "' thick, 

 and called a. Two of these dells, containing different liquids and 

 placed one behind the other, gave the physically mixed spectra. 

 For the chemically mixed spectra the two solutions were mixed 

 in the proportion of 1 : 1 and placed in a glass cell whose interior 

 width was 10+a ram , and whose glass sides wwv a"" a thick. A 

 glass plate of thickness a was placed within the liquid and a 

 second one outside, both being perpendicular to the light-rays. 

 The liquid layer has thus the same thiokucs> ;h in the previous 

 case, 10 mra , the glass absorbing layer has the same thickness, !<', 

 and there are as before 4 reflections between liquid and gla-s ;l nd 

 4 between air and glass. As an illustrate..!, the action of a. pe- 

 ons solutions of pararosaniline (fuchsiue), and trinil ropheiiol 

 (picric acid), is described. The former showed t he strong absorp- 

 tion bands from A=570'4 to 518-2 the intensity diminishing — 



hie end to A=429-6, where it again suddenly increased. The lat- 



W Inn the two cells were interposed, the strong bands at 

 A=570-4 — 518-2 appeared, and also the strong absorption begin- 

 ning at ,\— fs:;-s. When a mixture of the two solutions was 

 examined, the absorption bands A = ."">7<>- 1 — "i I s--j had disappeared 

 and a pretty strong absorption from A=576-9 toward the violet 

 had taken its place, while from A = tsa-s no distinct color could 

 be recognized. These changes have unquestionably a chemical 

 origin. If, how-eve?-, solutions of neutral potassium chromato and 



■rpo.cd spectra show in the region E26F— E45F, a ligh 



v of o-2o0t; and Ei'r.i F- KsoF of o-:u» 1, corresponding t 

 it ict ion-coefficients £,=0-52784 and £ 3 =0-44250. Thes 

 ■nts, calculated by Yierordt's formula" from his -lata, at 



