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Kapok—a new textile fibre
March, I916.]
CURRENT Topics.
443
spark appears to be the consequence and not the cause of the explosion. Experiments such as this suggest the ionic origin of ignition. It has been shown that when a hot wire or spark is the source, ignition only occurs when ionization is produced, and ionization alone without heat has been found to be capable of producing ignition.
The Heat-insulating Properties of Commercial Steam Pipe L. B. I~[C~/[ILLAN. (Proceedings of The American Society of Mechanical Engineers, December 7 to IO, I915.)--Most Coverings.
of the early results of tests of the value of steam pipe non-conducting coverings apply at only one temperature or two, at most, and for one or two thicknesses; they are not applicable to modern conditions involving high superheat and thicker coverings. The work which this paper describes has been carried on for a period of about two years at the University of Wisconsin, and every effort has been made to secure accurate and consistent results. The effect on heat losses of varying the temperature difference between pipe surface and air between o ° and 500 ° F. has been thoroughly investigated, and the conclusions reached are fully explained. Different thicknesses of material from o to 3 inches were tested, and the laws confirmed by the results of these tests permit their application to any thickness whatsoever; and the drop in temperature from steam in a pipe to the inner and outer surfaces of the pipe wall under various conditions may be accurately determined. Another new fact disclosed is that the loss from any covered pipe is a function of the temperature difference between the surface of the covering and the surrounding air; and that this function is the same for all coverings having the same character of surface, regardless of what the other properties of the covering may be, since the effects, if any, of these properties appear in the temperature difference. The value of the function has been determined for canvas-covered surfaces, and a complete explanation of its significance is included.
Kapok--a New Textile Fibre. J. BOYER. (Scientific American Supplement, vol. lxxxi, No. 2094, February 19, I916.)--A French inventor, M. Jean Mondamert de S,t. Ren6, has just created a new industry in textiles by discovering a method of carding, spinning, and weaving kapok. This is a silky down from the Bomba¢: ceiba or Eriodendron anfractuosum (silk cotton trees), which are well distributed in the tropics, especially in the West Indies, South America, and the Soudan. At the moment there are fifty establishments m Java collecting this vegetable wool, while five men have .been at work with it alone for about a dozen years. Javanese kapok is composed of threads of a clear yellow, somewhat silky in texture and one-half to three-quarters of an inch in length, and is contained in the long capasudal fruit of the tree. In the midst of the mass of threads constituting a floss there are to be
444
CURRENT TOPICS.
[J. F. I.
found, previous to working it, seeds of an inch to an inch and a quarter in diameter, of dark brown color. On examining the floss with a microscope it is seen to be composed of unicellular fibres o,f the length above given, cylindrical throughou4t most of the length, and with thin walls and a light skin near the .base. The central tube, filled with air, gives to the fibre its very valuable lightness. Aside from .their lightness, the fibres of kapok possess absolute impermeability to water, due, according to Dr. Clave1, to, the presence o,f a vcax with which the filaments are coated. This is described by M. de St. Ren6 as a " solidified oil," who calls attention ,to the membranous nature of the covering. However this may be, kapok, through its inaptitude to accept water and the quickness with which it dries, does not rot. It will support from thirty to thirty-five times its weight in water, while ordinary cork will float only about five ~times its weight. Experiments have shown that a packet of kapok which sustained thirtytwo times its weight when first immersed would still hold up twentysix times its weight at ~the end of a month in water. No other vegetable substance known has this extraordinary ratio of flotation power and impermeability: it is an attribute of down B o m b c ~ x alone. On account of its elasticity and its lightness, kapok is admirable for the stuffing of cushions or mattresses, replacing advantageously feathers, wool, or hair. Again, its conduct in the water makes it superior for life-preservers, " c o r k " jackets and other items for life-saving in rivers of the sea.
PRES~ OF ~.1~. L I P P I N C O T T
COMPANY
PHILADELPHIA
CURRENT Topics.
443
spark appears to be the consequence and not the cause of the explosion. Experiments such as this suggest the ionic origin of ignition. It has been shown that when a hot wire or spark is the source, ignition only occurs when ionization is produced, and ionization alone without heat has been found to be capable of producing ignition.
The Heat-insulating Properties of Commercial Steam Pipe L. B. I~[C~/[ILLAN. (Proceedings of The American Society of Mechanical Engineers, December 7 to IO, I915.)--Most Coverings.
of the early results of tests of the value of steam pipe non-conducting coverings apply at only one temperature or two, at most, and for one or two thicknesses; they are not applicable to modern conditions involving high superheat and thicker coverings. The work which this paper describes has been carried on for a period of about two years at the University of Wisconsin, and every effort has been made to secure accurate and consistent results. The effect on heat losses of varying the temperature difference between pipe surface and air between o ° and 500 ° F. has been thoroughly investigated, and the conclusions reached are fully explained. Different thicknesses of material from o to 3 inches were tested, and the laws confirmed by the results of these tests permit their application to any thickness whatsoever; and the drop in temperature from steam in a pipe to the inner and outer surfaces of the pipe wall under various conditions may be accurately determined. Another new fact disclosed is that the loss from any covered pipe is a function of the temperature difference between the surface of the covering and the surrounding air; and that this function is the same for all coverings having the same character of surface, regardless of what the other properties of the covering may be, since the effects, if any, of these properties appear in the temperature difference. The value of the function has been determined for canvas-covered surfaces, and a complete explanation of its significance is included.
Kapok--a New Textile Fibre. J. BOYER. (Scientific American Supplement, vol. lxxxi, No. 2094, February 19, I916.)--A French inventor, M. Jean Mondamert de S,t. Ren6, has just created a new industry in textiles by discovering a method of carding, spinning, and weaving kapok. This is a silky down from the Bomba¢: ceiba or Eriodendron anfractuosum (silk cotton trees), which are well distributed in the tropics, especially in the West Indies, South America, and the Soudan. At the moment there are fifty establishments m Java collecting this vegetable wool, while five men have .been at work with it alone for about a dozen years. Javanese kapok is composed of threads of a clear yellow, somewhat silky in texture and one-half to three-quarters of an inch in length, and is contained in the long capasudal fruit of the tree. In the midst of the mass of threads constituting a floss there are to be
444
CURRENT TOPICS.
[J. F. I.
found, previous to working it, seeds of an inch to an inch and a quarter in diameter, of dark brown color. On examining the floss with a microscope it is seen to be composed of unicellular fibres o,f the length above given, cylindrical throughou4t most of the length, and with thin walls and a light skin near the .base. The central tube, filled with air, gives to the fibre its very valuable lightness. Aside from .their lightness, the fibres of kapok possess absolute impermeability to water, due, according to Dr. Clave1, to, the presence o,f a vcax with which the filaments are coated. This is described by M. de St. Ren6 as a " solidified oil," who calls attention ,to the membranous nature of the covering. However this may be, kapok, through its inaptitude to accept water and the quickness with which it dries, does not rot. It will support from thirty to thirty-five times its weight in water, while ordinary cork will float only about five ~times its weight. Experiments have shown that a packet of kapok which sustained thirtytwo times its weight when first immersed would still hold up twentysix times its weight at ~the end of a month in water. No other vegetable substance known has this extraordinary ratio of flotation power and impermeability: it is an attribute of down B o m b c ~ x alone. On account of its elasticity and its lightness, kapok is admirable for the stuffing of cushions or mattresses, replacing advantageously feathers, wool, or hair. Again, its conduct in the water makes it superior for life-preservers, " c o r k " jackets and other items for life-saving in rivers of the sea.
PRES~ OF ~.1~. L I P P I N C O T T
COMPANY
PHILADELPHIA