40) REPORTS UN THE STATE OF SCIENCE.—1917. 
theory is G. von Georgievics.? He has a long line of predecessors, from 
the earliest dyeing theorists of the first half of the 18th century, Hellot.® 
Dufay,4 Macquer,® and Le Pileur d’Apligny.® down to Walter Crum,’ 
Persoz, Engel, and Napier. He rejects categorically the theory of chemical 
combination between dye and fibre in the case of wool, on the grounds 
that such indifferent substances as glass beads, kaolin, and various other 
inorganic substances may be dyed in exactly the same way. He objects 
in details to O. Witt’s theory of ‘ solid solution’ (of the dyestuff solute 
in the fibre solvent) by combating each of Witt’s statements from experi- 
ments of his own. His theory ot the dyeing process is that the dye par- 
ticles are in a state of adhesion on and in the fibre, and neither of solution 
nor chemical combination ; the same he considers to be true of the various 
mordants. But this ‘ adhesion ’ is, he says, analogous to capillary attrac- 
tion, to the adhesion of solute to solvent, and to that exerted, for example, 
by glass on a liquid which * wets ’ it, and such forces as these, he admits, 
lie on the borderline between chemical and physical forces. A very 
similar conclusion had been drawn before by H. v. Perger,® L. Hwass,°® 
and G. Spohn.?° 
Georgievics admits that basic dyestuffs when dissolved in water are 
dissociated, and that if the base has an attraction for a substance, a coloured 
body will be formed when the two are brought together. As evidence 
for the physical and against the chemical nature of dyeing, he relies chiefly 
on various forms of Henry’s law of distribution. 
He states from his experiments that in the majority of cases dyeing 
takes place according to the equation 
AE 
8 
= constant 
Cw Y 
in which C, denotes the colour taken up by the fibre, Cw that left in the 
bath and 2 indicates the affinity of the colouring-matter for the fibre. 
In some later experiments" with indigo extract and picric acid on wool 
and methylene blue on mercerised cotton, he states that dyeing proceeds 
according to the equation 
VC dyebath _ 
C fibre 
where « may be equal to one or greater than one and its value depends 
upon the temperature and additions to the bath. The rule only holds 
within certain limits of concentration of the dyebath, comparatively 
more colour being taken up from dilute than from concentrated baths. 
2 Mitteilungen des K.K. Gewerbemuseums in Wien, pp. 165, 205, 349 (1904), p. 345 
(1905). See also Journ. Soc. Dyers and Col. 1895, pp. 79 and 121. 
3 1734, L’art de la teinture des laines et des étoffes de laine. 
41737, Traité sur la Teinture, observations physiques sur le mélange de quelques 
couleurs & la teinture. 
1763, L’art. de la teinture de la sote. 
6 1776, L’art de la teinture des fils et étoffes de coton. 
1843, Journ. Chem. Soc. 16, 1, p. 404. - 
‘Einige Farbersuche,’ in Farbenzeitung, 1890-1. 
Farbenzeitung, 1890, pp. 221, 243. 
Essay, ‘ Zur Erkenntnis des Farbevorganges’ in Dinglers’ Polytech. Jour. 1893. 
11 Journ. Soc. Dyers and Col. 1904, p. 105. 
a 
cS wn 
