Leather ageing

Louis Pasteur [1822-18951 was born at Dole in the Jura region of France, the son of leather tanners. After receiving his doctorate from the Ecole Wormale Superieure at age 25, his landmark discovery of tartaric acid... 

So fierce was this one that it seemed an age before I saw that she had returned and held something before my eyes a strip of silk and leather, dark and stained with age, stitched with curious signs I could not read and a fat and smiling dragon. It s the girdle, Ysa Saint Margaret s girdle. Now all will be well. ... 

Figure 6.2 A ceremonial Masonic leather apron bears several symbols. Inside the circular ouroboros in the center is the primary Masonic symbol, the square and the compass joined, which is a reference to the alchemical squaring of the circle. The skull of Hiram is in the middle of that, and the landscape below is the Temple of Solomon with the two pillars, named Boaz and jakin, in front. The great pyramids are in the bottom left comer. (Manly P. Hall, The Secret Teachings of All Ages [1995])...

Measurement of pH is a potentiometric technique frequently used for measuring the degree of the deterioration of materials that are subjected to natural aging. The determination of pH levels is commonly carried out on ethnographic objects manufactured with parchment or leather, and it is especially relevant in altered paper due to the formation of acidic compounds from the decomposition of the woodpulps and other raw materials, which can induce the hydrolysis of the cellulose and then decrease the resistance and mechanical properties of the document [29]. 

Alizarin, a naturally occurring anthraquinone, exists as coloring matter in madder. In the middle ages the red color of the famous cordovan leather (leather from Cordoba, Spain) was created by mordanting with alum. Nowadays, anthra-... 

The female emu begins to breed between 18 months and 3 years of age, and may continue to produce eggs for more than 15 years. The emu grows to full size within 2 years, when it is 1.5-1.8m and weighs up to 65-70kg. Emu products include leather, meat and decorative eggshells. Emu oil is sold for cosmetic and pharmaceutical purposes. Emu meat, like ostrich meat, is similar in texture and colour to beef. 

We now well appreciate, of course, that polymers are virtually everywhere. Some of them occur naturally, and we continue to better understand their compositions, structures, and properties. Many of these materials have been used since the dawn of human existence, for food, obviously. Cellulose alone has been essential for clothing, fire, shelter, tools, weapons, writing, and art. Leather is probably the result of the first synthetic polymer reaction, essentially the crosslinking of protein (elastin). How we progressed over time to the Polymer Age is a fascinating series of stories, some of which are well worth recounting here. 

Of the nine published requirements, the morpholine process appears to meet seven—those specified for cost, pH, penetration, permanence, odor, lack of toxicity, and uniformity of treatment. It meets the eighth requirement—avoidance of new problems—to only a limited extent because of the occasional color changes of pyroxylin covers and the darkening of leather. The ninth requirement—reserve alkalinity—is not met in a literal sense, but aging in sulfur dioxide indicates it is met in at least one case where it is needed. 

She led me into a lar, wood-panelled room An age-worn leather chesterfield faced a fire on wtrich a pile of fogs were gbwing The carpet was Persian, old but still beautifiil Surrounding it were bare floorboards burnished to a deep unber. The room smelled appealing of pine and wood smoke. 

Elk are no longer domesticated though they were used as beasts of burden during the Middle Ages. They are hunted for their meat and their antlers are taken as trophies. Shed antlers can be put to the many uses listed later in this chapter, and elk skin makes a very strong leather. Items made from these materials are often found in souvenir shops local to elk habitats. 

Making horn objects was not a cottage industry. By the year 1284 there was a homers guild in London, which still exists today, and which is now called the Worshipful Company of Homers. When first formed, they controlled the sale and purchase of horn within a radius of 24 miles of London. They protected the homers rights and their welfare, and they kept an eye on the quality of the work produced. As the years passed they amalgamated with the leather bottle makers, and, finally, in 1943, with the plastics industry - today s equivalent of the horn of the Middle Ages. 

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