166 Proceedings of Indiana Academy of Science 



Those forming compounds with pronounced colors are inclosed in the 

 circles. It is of interest to note in connection with the latter series of 

 elements that, (a) the most common ones have the consecutive atomic 

 numbers 22 to 29; (b) two other series of consecutive numbers are 

 included; (c) all the transition elements are included; and (d) those 

 not in the transition groups are substantially the ones adjacent to them. 

 Although there are some colored compounds of the elements not already 

 mentioned, it is probable that few of them will prove of value for the 

 preparation of colored solutions. 



PERIODIC TABLE 



IH 



Moa 



ZHe 5b iBe SB eC 7N 60 9F 

 too 6.31 9.1 /as /2.00S /tooe /tjOO IM 



loNt 1 1 No izMg i5m i4Si ISP 16 S nCl 



Zg^ £jo tf^ 4SP E^ sjjil 



/aA' isK" zoci 



J«9 59.10 1007 



e£.3z oi.is ezti e9.3s 9o.* 



SfX2 SSd S(BS 57 LS SBCe 

 /xut laa /57.S7 /se.o /lae 



I I J- -1- ^ 75TaC7, 



/ai.s 



aiA/fen—) asR^esAc aoTh aiP/kOz. 

 e£z.-t eei.0 ifzHi zsi.i One/ 



W\ao/f} BiTI ezPb esBi ail\> es(-) 

 aoai eoi.o zoin ecs.o (fi/ci 



Sa£M. f^^fh e/^m»n fa 



S7lJ 5eCeS3i^^fk6l(—)(z^ £3& 6f€J 

 JS3.0 /KXE \(«y Vtty \S0J ISBX) IS25 



£S7h UDy £7Ho(i^iS%i70Yi liiJ 7ZT:,n 

 IS3B liZS liS.5 \4jJ lta.S I7S^ I7SO (j7£l) 



Fig. 1. Showinv: the location in the i)eii(xlic table 

 colored compounds. 



)!" the chief elements forminfj; 



Require uientH of a SuLisfuctoii/ l'er))ia)ievt Color Standard. Any 

 solution to be considered as a possibility for a permanent color standard 

 must first of all possess a color suitable for the purpose in hand, or be 

 capable of giving it through proper blending. The color must be uni- 

 form throughout the solution and must not change in intensity or hue. 

 To be suitable for general use the color must be such as to be accurately 

 and readily reproducible. Furthermore, if two or more solutions are to 

 be mixed in order to obtain some blend of the original colors, the solutes 

 and solvents must be of such a nature that no reaction occurs on mixing 

 which destroys the expected, resultant color. The intensity of the color 

 must be sufficient — this requirement would practically eliminate the 

 use of such compounds as manganous salts whose color in .'solution is 

 very definite but relatively low in intensity. In general it is desirable 

 to have dilution of a colored solution result merely in a decrease in 

 intensity of the color rather than in a real change of color". 



= Sheppard— Photo-Chemistry. )). 1.53, 159 (1914). 



