88 THE SCIEKTIFIC ASPECTS OF TANNING. , 



exclusively, which, like all leather tanned under pressure, proved 

 of very inferior quality. It is widely employed now with other 

 agents. Gambice deposits no bloom, gives no gallic acid, and in 

 its action on the hide the resulting tanno-gelatine does not 

 appear to be so complete or thorough a chemical combination as 

 most of the other tanning materials. 



Catechuic acid is also present in Gambice, which is insoluble in 

 cold watdT; precipitates with acetate of lead, but not with gelatine. 

 Continued application of warm water, and even the perspiration 

 in hot water, acting on the Catechuic acid in the leather, releases 

 a considerable portion, causing a red stain. 



Tormentil roots were used about lOo years since in the 

 Hebrides for tanning purposes, containing 3 1 per cent of tannic acid. 



We have lastly to speak of Hemlock extract, " Ahies Canadensis.'' 

 It is brought to England in casks from America, with about the 

 consistency and colour of treacle, — according to Ramspacker, 

 giving 25 per cent of tannic acid. Being one of the latest intro- 

 ductions, great variety of opinion is expressed as to its value. 

 When used in excess it gives the leather a brownish red tinge, 

 which is undesirable. The large quanitties which now reach our 

 shores, as also the leather tanned with it in America, which over- 

 whelms us, will, we imagine, do more to revolutionize our trade 

 than anything which has occurred of late years. It appears 

 inevitable, that tanning materials and leather, fwith very few 

 exceptions, will be dragged down to its level. The Tanners of 

 England would have no cause to complain were they as a trade 

 placed on a similar footing with their trans-atlantic brothers ; but 

 whilst we admit this cheap and inferior leather duty free, every 

 ton of leather which we forward to New York has to pay a duty 

 of 30 per cent. This is an American idea of reciprocity. We 

 had the pleasure lately of perusing a letter from the most eminent 

 tanner of the United States, in which he predicts that their cool- 

 sweated. Hemlock-tanned leather will prove to be the sole leather 

 worn by the ordinary millions of Europe. The British tanner is 

 equally sanguine that he can do as much if they all start fair. 



