Collegium Volume 239-289

Collegium Volume 239-289

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...1901, p. 14) state on abundant evidence that Sumach-tanned leathers are less affected by light and gas fumes, and less liable to decay and form rot" than those of any other known tannage. Sumach is frequently adulterated with leaves and twigs of Pistacia lentiscus, Coriaria myrtifolia, Ta-marix africana, Ailantus gladulosa, Vitis vinifera and other species of the Rhus family, but Pistacia lentiscus is used to a much larger extent than any of the others. Pistacia, coriaria and tamarix all contain considerable quantities of catechol tannins, whilst the genuine sumach yields a tannic acid belonging to the pyrogallol group. These catechols are. frequently the cause of the rotting of sumach-tanned leather. The most satisfactory methods of detecting the adulterants are Procter's Bromine-water test or the microscopic examination. The most important work on the microscopic structure of the tissues of sumach and its adulterants was done by the late An dreasch (Sicilianischer Sumach und seine Verfalschung. Wien 1898); further investigation in this particular direction was made by M. C. Lamb and W. H. Harrison (Journal Soc. Dyers and Colourists, March 1899), M. C.Lamb (ibid. December 19041) and H. Pri estman (Journal Soc. Chem. Industr. March 1905)?) There is also a qualitative test suggested by M.Nierenstein3) (Chem. Zeitung, 1906, N0. 72 4), who finds that Diazobenzolchloride gives marked precipitates with catechol and none with pyrogallol tannins. All methods, however, give only qualitative values. N0 quantitative method has, so far, been suggested, with the exception of our preliminary communication on the subject, read before the Meeting of the British Section (International Association of Leather Trades Chemist) on...show more

Product details

  • Paperback | 190 pages
  • 189 x 246 x 10mm | 349g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236859219
  • 9781236859211