If cotton fabrics are to be used outside, micro-organisms are not the only influences responsible for their deterioration. Chemical tendering brought about by sunlight, air, and water also plays an important part. Unless the fabric is coated with some impervious material, no finishing treatment yet found completely reduces this atmospheric degradation. Many finishes give partial protection to fabric, however, although some mildew-resistant finishes hasten deterioration.

For this study, in order to determine the protection these mildew-resistant treatments give after weather exposure, samples of the treated fabrics were exposed to the weather for 6 weeks at Beltsville. They were tacked on racks, which faced the south and were inclined about 30 to the horizontal, so they were exposed to the sun all day. After 6 weeks, the fabrics were removed and cut into strips. Some were used for obtaining the breaking strength of the weathered material, the others were tested for their resistance to mildew.

In determining the effectiveness of the finishing treatments after laundering, additional treated samples were washed in a 0.5 percent neutral soap solution at 38 C. The strips, five similarly-treated strips to a jar, were agitated in the soap solution for half an hour and rinsed in four changes of water. Then they were tested for mildew resistance by the soil-suspension method.

Although losses from termite attack are not so general as losses from micro-organisms, they can be very great and cause enormous waste.

Some of the treated fabrics reported here were also tested for their resistance to termite attack by a method recently developed in cooperation with the Bureau of Entomology and Plant Quarantine. Test samples of the treated fabrics were kept for 130 days on moist ground in a wooded area where a natural infestation of termites was known to exist. In preparation for the test, sticks and other debris on the surface of the ground were removed and an ordinary paper towel was placed on each cleared space and covered with a piece of 2 by 4 wood. The soil was carefully packed around the edges of the wood in order to conserve moisture. As soon as termite activity was noted beneath the paper, the fabric sample to be tested was inserted between the paper and the wood.

The resistance of the treatment to termite attack was measured by the extent to which it protected the fabric from damage. The following five degrees of infestation or damage to the strips were recognized : Heavy, 25 percent or more of the sample destroyed; medium, less than 25 percent of the sample destroyed, but more than three penetration holes; light, from one to three penetration holes; trace, no penetration holes, but light surface feeding; and none, sample undamaged.

Most of the finishes that were selected colored the fabric. Several finishes containing copper made the material blue: Copper sulfate with soap, copper naphthenate and oleate, and cuprammonium fluoride and hydroxide. The treatments using copper sulfate with 8-hydroxyquinoline colored the cloth greenish yellow. Similar treatments combining magnesium sulfate, stannous chloride, aluminum acetate and mercuric chloride with 8-hydroxyquinoline made the fabric light cream-colored, yellow, greenish yellow, and yellow orange, respectively. Lead acetate with potassium dichromate produced a yellow color. In general the natural dyes developed shades of yellow and brown. Quercitron and divi divi made the material mustard colored. The fabric dyed with Osage orange Was rust brown and that dyed with quebracho and cutch, chocolate brown. Fustic and logwood made the fabric greenish yellow and steel gray, respectively. The three other finishes did not color the material.

None of the treatments weakened the fabric. Some appreciably strengthened it. All except three of these treatments gave excellent protection against mildew and rotting. However, additional cuprammonium fluoride in the fabric makes this treatment equally as effective as the others. Cadmium chloride with soap was not effective although in previous studies it made cotton resistant to Chaetomium globosum.

In general, exposure to weather greatly lowered the breaking strength of the treated material. However, 14 of the 23 weathered treated fabrics retained most of their original strength and were somewhat stronger than the untreated weathered control. When tested for their resistance to mildew, the results showed that 11 of the 14 treatments still gave excellent protection. They are : Copper naphthenate, copper naphthenate with copper oleate, copper oleate, cuprammonium fluoride, cuprammonium hydroxide, copper sulfate with 8-hydoxyquinoline, salicylanilide, and two treatments each of osage orange and quercitron extract applied with copper sulfate and potassium dichromate.

On laundering the treated fabrics and subsequently determining their resistance to mildew, the results indicated that 8 of the 11 treatments listed above, and also mercuric chloride with 8-hydroxyquinoline, were still effective. cuprammonium fluoride, cuprammonium hydroxide, and salicylanilide gave no protection after laundering.

In regard to resistance against termite attack, all of the finishing treatments that contained copper and mercury in their formulation-including the natural dyes-gave good to excellent protection to the fabric. All other treatments, under the conditions of this test and in the concentrations used, were ineffective in preventing termite damage.

Protective treatments for cloth must be nontoxic. If the finishes are to be used for sheets, towels, or wearing apparel, certainly tests should be made to determine whether or not the treated fabric will cause dermatitis. Another point worthy of considerable developmental work : Treatments should be practical and simple enough that they can be applied in the home without excessive cost or special equipment. Also, the behavior of treated materials on prolonged use or storage at various temperatures and humidities should be known.

THE AUTHOR Margaret S. Furry is a textile chemist in the Bureau of Human Nutrition and Home Economics. Besides her publications on mildew prevention Miss Furry is the author of one of the Department's most popular bulletins, Stain Removal from Fabrics: Home Methods, as well as various technical bulletins on starches and sizes used in finishing cotton fabrics, and circulars giving methods for home dyeing with both commercial and natural dyes.