14 LEATHER INVESTIGATIONS I SOLE LEATHERS. 



In the last stages of tanning, the leather is in contact with practi- 

 cally fresh normal liquors in which the relations just stated hold. 

 Therefore the tannins and nontannins of the water-soluble extracts 

 from leather will tend to approximate the same ratio to each other as 

 the liquors in which it was tanned. If the sum of glucose and 

 magnesium sulphate is subtracted from the figures for the non- 

 tannins in any particular leather, the difference approximates the 

 nontaraiin figures for the liquor in which the final tanning of the 

 leather was conducted. A comparison of this figure with the figures 

 for soluble tannin shows the ratio of tannin to nontannin in the 

 liquor, and in many instances proves conclusively that tanning 

 materials other than oak or hemlock bark were used. In fact, the 

 ratio indicates that quebracho was used, but no intimation of the 

 fact is given in the branding of the leather. The branding of all 

 leathers "oak," "hemlock/' or "union" is deceptive and the 

 practice should be discontinued. No leather should be branded oak, 

 hemlock, or union which is not tanned entirely with oak or hem- 

 lock or a mixture of the two. 



The misbranding of leather is indicated by the recent census 

 statistics. The percentage of oak leather reported in 1909 is 7 per 

 cent greater than in 1904; the percentage of union leather is 32 

 per cent greater in 1909 than in 1904; while the quantity of hemlock 

 and oak barks and extracts used in 1909 is materially less than in 

 1904. 



PREVENTION OF WEIGHTING AND BLEACHING. 



It is improbable that the present practices of weighting and 

 bleaching sole leather will be voluntarily discontinued by the tanner. 

 Intelligent buying on the part of the public will do much to break 

 up these practices. The individual purchaser of course can not 

 know whether the leather in the shoes he buys is weighted or has 

 been bleached, but if he will insist that they shall not be made of 

 weighted or bleached leather and will not buy from those manu- 

 facturers who make such leather, the quantity of leather so treated 

 will materially decrease, and it will be found that shoes are more 

 durable and consequently less expensive. 



The weighting and bleaching of leather may be easily and abso- 

 lutely controlled by concerted action on the part of the shoe manu- 

 facturers. It is very simple for them to determine whether the sole 

 leather delivered is weighted, and if they will refuse to buy such 

 leather it will not be made. Shoe manufacturers will see to it that 

 sole leather is not weighted if the public will take sufficient interest 

 in the matter to demand unweighted leather. 



