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Natural resin origins
CURRENT TOPICS. Natural Resin Origins.--(A. J. GIBSON, Chem. & Ind., 52, 58.) Copal.--The copals are the resinous exudations mainly from species of Coniferae occurring in East India, East Africa, West Africa and South America. These resins may be classified into hard, medium and soft copals. The quality of copal decreases with increased specific gravity and the property of oil-solubility is imparted by an old established process known as "running" and is the heating of small batches of resin accompanied by a loss in weight and added solubility in oils. Dammar.--The dammars represent those resins derived from trees belonging to the large tropical tree-family of the Dipterocarps. A peculiarity of the resins is their insolubility in alcohol and their complete solubility in coal-tar hydrocarbons, turpentine and also petroleum hydrocarbons. The trees producing these resins are found in the East Indies, the Malay Peninsula, and the islands of the Pacific generally. De-waxed dammar is also in demand and research has been done to remove its undesirable component the "b-resene." Kauri.--This resin is both fossil and recent and is obtainable from a species of Arancarineae. Captain Cook mentions kauri in his diary of November, 1769 but it did not achieve commercial importance until three-quarters of a century later. The fossil gum is known, as "range g u m " or "swamp g u m " while the new resin from tapped trees is known as "bush gum." Lac.--Most of this resin, about 97 per cent., is produced in India. It is unique in being an animal product, unlike most of the natural resins which are of vegetable origin. Lac is the resinous incrustation of a small-scale insect living on certain trees. This incrustation is a rigid protective armor that causes little or no inconvenience since the insect has no power of mobility throughout the greater part of its life-cycle. The raw material for the resinous crust is sucked from the tree and is converted in what must be the most compact and well-equipped laboratory in the world--for the insect is only 1/32 in. long--into what is known as sticklac, consisting of a water-soluble dye, a compound wax, an alkali-soluble dye, moisture, sugars, soluble salts and the two true lac resins whose constitution is still under investigation. The magnitude of production is such that it is rated in grams per thousand insects, yet the total annual production approximates sixty-five million pounds. I26
July, I933.]
CURRENT TOPICS.
I2 7
Lac has been known for centuries, but the insect was first described by F a t h e r Tachard of the Society of Jesuits, 17o9 and was named after him Tachardia lacca. The name has altered m a n y times, the latest being Laccifer lacca. Sticklac usually is harvested by the natives who strip it off the tree, crush, sieve and wash it, this last process removing the water-soluble dye. Dried in the sun, this forms the seed-lac of commerce. The seed-lac is converted by a primitive heat process into button lac and shellac. C.
Invention of the Toothbrush.--(White Metal News Letter.) The invention of the toothbrush grew out of the famous Gordon Riots of I78O which took place in London. William Addis the inventor, who was being sought as an alleged participant in the riots, hid in the home of a leather tanner where he amused himself by carving bone, in those days a fashionable art. At that time the cleaning of teeth was a crude operation, the process being carried out by a single twig which was shaped like a chisel, and rubbed over the teeth with an up-and-down motion. Wanting something better, Addis bored a few holes in a piece of bone, cut some hairs from the tail of the nearest cow hide, thrust these into holes and thus became the maker of the first toothbrush. Toothbrush handles t o d a y are generally made from celluloid. The bristles are mainly obtained from Siberian pigs, the wild species producing the best, having hair which is both long and stiff. Special machines are used to insert the tufts of bristles in the handles, and each tuft is firmly secured by a nickel siver anchor. C. Locomotives, Past, Present and Future.--(L. F. LOREE--To the American Members of the Newcomen Society.) The first steam locomotive was operated by Richard Trevithick on Christmas Eve, in ~8oI. The final supremacy of this method of transportation was established on Oct. 6, I839, by George Stephonson's engine, the " R o c k e t " in the competitive trials at Rainhill on the Liverpool and Manchester Railway. T h e " R o c k e t ' s " performance demonstrated the practicability of operating an engine with wheels having smooth rims over smooth steel rails. Even with the large modern locomotive it is seldom realized how small is the area of contact between the wheel and rail. It is about one-third of a square inch for each wheel, a space about as large as one's thumb-nail. The first locomotive to be operated in the United States was the "Staurbridge L i o n " which was put into service on the Delaware and Hudson in I829. The latest locomotive placed in operation on this
July, I933.]
CURRENT TOPICS.
I2 7
Lac has been known for centuries, but the insect was first described by F a t h e r Tachard of the Society of Jesuits, 17o9 and was named after him Tachardia lacca. The name has altered m a n y times, the latest being Laccifer lacca. Sticklac usually is harvested by the natives who strip it off the tree, crush, sieve and wash it, this last process removing the water-soluble dye. Dried in the sun, this forms the seed-lac of commerce. The seed-lac is converted by a primitive heat process into button lac and shellac. C.
Invention of the Toothbrush.--(White Metal News Letter.) The invention of the toothbrush grew out of the famous Gordon Riots of I78O which took place in London. William Addis the inventor, who was being sought as an alleged participant in the riots, hid in the home of a leather tanner where he amused himself by carving bone, in those days a fashionable art. At that time the cleaning of teeth was a crude operation, the process being carried out by a single twig which was shaped like a chisel, and rubbed over the teeth with an up-and-down motion. Wanting something better, Addis bored a few holes in a piece of bone, cut some hairs from the tail of the nearest cow hide, thrust these into holes and thus became the maker of the first toothbrush. Toothbrush handles t o d a y are generally made from celluloid. The bristles are mainly obtained from Siberian pigs, the wild species producing the best, having hair which is both long and stiff. Special machines are used to insert the tufts of bristles in the handles, and each tuft is firmly secured by a nickel siver anchor. C. Locomotives, Past, Present and Future.--(L. F. LOREE--To the American Members of the Newcomen Society.) The first steam locomotive was operated by Richard Trevithick on Christmas Eve, in ~8oI. The final supremacy of this method of transportation was established on Oct. 6, I839, by George Stephonson's engine, the " R o c k e t " in the competitive trials at Rainhill on the Liverpool and Manchester Railway. T h e " R o c k e t ' s " performance demonstrated the practicability of operating an engine with wheels having smooth rims over smooth steel rails. Even with the large modern locomotive it is seldom realized how small is the area of contact between the wheel and rail. It is about one-third of a square inch for each wheel, a space about as large as one's thumb-nail. The first locomotive to be operated in the United States was the "Staurbridge L i o n " which was put into service on the Delaware and Hudson in I829. The latest locomotive placed in operation on this