RECORDS 



OF 



GENERAL SCIENCE 



MAY, 1835. 



Article I 



On Calico-Printing. By Thomas Thomson, M.D., F.R.S., 

 L. and E., &c, Regius Professor of Chemistry in the 

 University of Glasgow. 



( continued from p. 173. ) 



In the paper on Calico-Printing inserted in the third 

 number of this Journal, I gave an account of the mode 

 employed, to prevent the fixing of the dye on particular 

 parts of the cloth, or of discharging it after it has been 

 fixed. At present, I mean to explain the methods practised 

 in the application of chemical colours to calicoes. 



The term chemical seems originally to have been applied 

 to certain colours, which were prepared by means of sub- 

 stances brought directly from the laboratory of the chemist, 

 as distinguished from those made of materials previously 

 in common use. They consist principally of solutions of 

 tin, mixed with decoctions of the various dyewoods ; and, 

 as the colouring matter of these woods is readily acted 

 on by the light, as well as by alkalies and acids, chemical 

 colours came to be understood as necessarily fugitive colours. 

 Chemical blue also, (a solution of Prussian blue in muriatic 

 acid, or perchloride of tin,) and various other topical appli- 



VOL. I. Y 



