10 JOUENAL OF THE MiTCHELL SoCIETY [OctoheV 



toluenes mentioned above was obtained by studying their melting 

 points and by mapping the results by means of triangular coordinates. 

 The results will be printed in full in a later number of the Journal. 



Neiv Naphthalene Dyes. A. S. Wheelek. 



Juglone is a compound known for over fifty years to be present in 

 walnut hulls. These hulls as well as other parts of the walnut tree 

 may be used to produce a rich brown dye and have long been so used 

 by the farmer's wife. The exact character of the dye is not known, 

 but most likely is a near derivative of juglone. The latter compound 

 may be synthesized from naphthalene. Another name for it is 

 5-hydroxynaphthoquinone. The halogen derivatives of such com- 

 pounds have been very little studied. If juglone is chlorinated or 

 brominated in the cold unstable addition products are obtained, but 

 these are readily converted by the action of alcohol into stable mono- 

 substitution products. If juglone is chlorinated or brominated in 

 hot solution stable higher halogenated substitution products are ob- 

 tained. All of the stable products act as dyes since they contain a 

 chromophore as well as an auxochrome group. Owing to the pres- 

 ence of the phenolic hydroxyl group they form easily soluble sodium 

 salts, practical for purposes of dying. The tribromo juglone imparts 

 a champagne color to silk, a tan color to wool and this may be changed 

 to various tints by the use of mordants. Cotton is not aifected unless 

 mordanted with tannic acid. Dichloro juglone gives a rich bronze 

 color to silk and the hydroxy dibromo- juglone a delicate lavender 

 which is markedly changed by mordants. Other dyes are being pre- 

 pared in this field and a patent to cover all has been applied for. 



The following papers appear elsewhere in this issue of this Journal. 



A Portable Printing Press for the Ecologist. Z. P. Metcalf. 

 8ome Generic Distinctions in Sponges. H. V. Wilson. 

 Our Rats, Mice, and Shrews. C. S. Brimley. 

 Reptilian Folldore. C. S. Brimley. 



The Distribution of Rhododendron Catawhiense, ivith Remarls on a 

 Neiv Form. W. C. Cokee. 



