THE scarcity of aniline colors and the rise in the price of imported fustic give a special timeliness to experiments carried on during the past three years by the Forest Service to determine the value of osage orange as a dyewood. Osage orange grows naturally in southern Arkansas, Oklahoma, and Texas and has been extensively planted in the Middle West.  It is a very strong and durable wood, valuable for many purposes, but chiefly used at present for wagon felloes and fence posts. Though utilized with exceptional care, a great deal of waste necessarily results from manufacture on account of the tree’s small size and irregular shape. Inquiries by the Forest Service indicate that between 40,000 and 50,000 tons of Texas and Oklahoma osage orange are available annually. It was the existence of this large amount of waste material and the fact that osage-orange extract was once used by the Indians to dye their blankets and other fabrics which prompted the Forest Service to determine the chemical nature of the dyestuff present and to compare it with that obtained from tropical fustic, the dyewood which osage orange most nearly resembles.

The war in Europe is responsible for practically quadrupling the importation of fustic. From 1905 to 1913 imports of fustic ranged between 3,000 and 4,500 tons annually. In 1914 this jumped to 7,000 tons, and in 1915, though complete figures are not yet available, it probably reached 14,000 tons.  On July 20,1914, chipped fustic was quoted at $0.015 to $0.02 a pound. On December 8,1915, quotations ranged from $0.05 to $0.07 a pound. Before the war solid fustic extract brought from $0.08 to $0.11 per pound; in December, 1915, quotations ranged from $0.025 up. One case is known of a large tannery in Milwaukee which, during the summer of 1915, paid more than $0.50 for 51° Tw. extract, which ordinarily is quoted at about three-fourths the cost of solid extract.

A study of the extract obtained by leaching the ground wood or shavings of osage orange with water showed the dyeing principles present to be morin or moric acid, and morintannic acid or maclurin, the same as those in fustic, and a very small amount of a third, unknown red constituent. This red constituent is found in relatively large amounts in fustic from some localities, for example Mexico, and in comparatively small amounts in material grown in Jamaica and South America. Its practical absence from osage orange, however, is an advantage rather than a defect, since any considerable quantity of it tends to reduce the purity of the shades obtained and to give them a muddy or murky appearance.

Samples of osage-orange wood in the form of shavings and sawdust were submitted to the Lowell Textile School, the New Bedford Textile School, the North Carolina College of Agriculture and Mechanical Arts, and the Georgia School of Technology for comparison with fustic in dyeing wool.

The summary of reports from these institutions showed that the character of the dyeing produced by osage orange is almost identical with that of fustic, each being a polygenetic mordant dyestuff. Osage orange can be used advantageously for self-shades, also in conjunction with logwood and other mordant dyes and with alizarine. With a tin mordant it gives a comparatively bright yellow; with an aluminum mordant, a somewhat greener and duller shade of yellow; with a chromium mordant, a series of tans and old-gold shades; and with iron and copper mordants, dark browns, chocolate, and olive shades.

Opinions differed as to the depth of the colors produced.  Some believed that the osage orange gave a deeper color than did fustic; others considered osage orange to have a tinctorial value only 75 or 80 per cent of that of fustic.  The difference was apparently due to differences in the fustic used for comparison. It is generally held in the trade that Mexican (also called Vera Cruz or Tehuantepec) fustic is better than either the Jamaica or Maracaibo (Venezuela).

All opinions concurred that the aluminum and tin mordanted colors produced by osage orange (and by fustic also) are too fugitive to be of commercial value. The chromium, copper, and iron mordanted colors, however, are all reported as of commercial value, the chromium color being especially resistant to light and washing. No difference could be noted between the osage-orange and fustic colors in any of the fastness tests.

Just how much tannin the material actually contains, as distinguished from dyeing principles, is impossible to say, since the two are so closely allied chemically. The material will tan and dye at the same time. Fustic acts similarly and is extensively used for retanning or “after-tanning” chrome (mineral) tanned leather, especially when it is later to be dyed some tan shade with basic aniline colors. The vegetable tannin color acts as a mordant for the aniline color and gives a good bottom tan color over the blue of the chrome, thus reducing the amount of aniline dye necessary.

In view of the striking similarity of results obtained by dyeing wool with osage orange and fustic, it is reasonable to expect that osage orange should be as valuable as fustic for dyeing leather. In fact, preliminary tests indicate that this is the case. Experiments made at a large tannery in Milwaukee on chrome-tanned calfskins show that here, too, osage orange gives the same shades and depth of color as fustic.

OSAGE ORANGE FOR COTTON.

Experiments are at present under way to determine the value of osage orange as a cotton dye. Ordinarily a dyestuff like osage orange would not be considered as suitable for cotton. The war, however, has deprived this country of its chief source of aniline colors. It is quite possible that for colored twines, cords, and similar materials where fastness and permanence are not essential, good shades may be developed that will fill the void left by the present shortage of aniline dyes.

The greatest hindrance to the commercial use of osage orange has been the high freight rates from the point of production to the North Atlantic seaboard. The center of production is several hundred miles inland, and the rail freight to a port like Galveston is practically as great as the total cost of transporting fustic from the interior of Mexico to New York or Philadelphia. Several concerns interested in the development of osage orange, however, are surveying the ground in the Southwest with the idea of erecting extract plants there. Should such a plan prove feasible, a long step will be taken toward the commercial exploitation of osage-orange dyes.

Since the yield from osage orange is about 80 or 85 per cent of that from fustic, the cost of operating an osage- orange plant will, of course, be somewhat greater than that for a fustic plant of the same capacity. This must be taken into account in comparing the two raw materials as a source of dye. Because osage orange is not at present on the market, it is difficult to give exact figures of cost. One concern in the East, however, states that, as compared with fustic, for which they paid $25 a ton in the spring of 1915, osage orange would be worth $14 a ton. As far as the actual cost of the two woods is concerned, osage orange has a distinct advantage over fustic. Quotations secured by the Forest Products Laboratory from osage-orange producers in the Southwest for culled fence posts and other forms of waste, not bark, averaged $5 a ton. With an extract plant in its region of production there will probably be a considerable margin in favor of osage orange even in normal times.