636 ALO^. 



from a jelly made of isinglass, whicH readily fuses and dis- 

 solves in warm water. 



This substance has attracted considerable attention in 

 France. It was exhibited at the Paris Exhibition of 1878 

 under the name of Thao. The following particulars from 

 the Catalogue may prove interesting. Various trials have 

 been made with it in France since 1874, especially by 

 MM. D. Gantillon & Co. at Lyons, and the Industrial Society 

 at Rouen. The thao is prepared for use in the following 

 way : — After having been soaked in cold water for about 

 twelve hours, it is boiled for a quarter of an hour, during 

 which it absorbs about 100 times its weight of water. If 

 allowed to cool it becomes a jelly, but if passed through 

 a sieve and stirred until cold, it remains fluid, and in this 

 state is more easily employed than when hot. The y ellowish 

 matter which some specimens contain can be removed 

 by boiling for some time, when it forms an insoluble scum, 

 which appears to consist of very thin fibres, and which remain 

 attached to the sides of the vessel. 



A singular property, and one which perhaps might be turned 

 to valuable account, is, that thao jelly does not decompose 

 solution of permanganate of potash even when left in contact 

 with it for twenty-four hours. 



According to M. Heilraann, of Eouen, thao produces, in the 

 proportion of 1 part to 1 00 of water, a dressing, which is supple 

 and strong, and which gives substance rather than stiffness 

 to calico, while dextrine, like starch, makes the tissue drier 

 and harder, and gives less facing to the thread. The addition 

 of glycerine gives a dressing still more flexible and soft, and, 

 while rendering the tissues less stiff, it communicates more 

 body to them. 



The addition of talc gives still greater smoothness. Once 



thao will mix while hot 

 The principal advan- 



dissol 

 with 



witn any gum, starch, dextrine or gelatine. The principal aavau 



tage of thao, in dressing silk fabrics is that while preserving 



their suppleness it gives them greater glossiness and m^^» 



