282 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Paper products, liber board, wall board, and water-resistant wrap- 

 ping pai)ers are rapidly replacing wood and even tin as containers 

 for certain kinds of food and merchandise. There are no methods 

 for testing these materials or insuring tiie manufacture of a satisfac- 

 tory box board that will withstand the forces of destruction met with 

 in transportation, especially in overseas shipments. Neither is there 

 anj'^ satisfactory method for determining the strength of fiber board, 

 wall board, corrugated board, or water-resistant baling papers. 

 ]Much Avork has been in progress in tlie last three years on tliese sub- 

 jects, and some of the results have been published in the form of a 

 description of an impact tester for fiber board, as well as a report 

 upon Avater-resistant papers for baling. 



The investigations relating to the water resistance of fiber board 

 and the adhesives used in the manufacture of solid and corrugated 

 fiber board and wall board have greatly stimulated the interest of the 

 industry, especially those on the eifect of silicate of soda Avhen used 

 as an adhesive on fiber board and on the value of the proper sizing of 

 the board in increasing its water resistance. Following the work of 

 the bureau on fiber board, the silicate of soda manufacturers and the 

 fiber board associations established two fellowships at the Mellon In- 

 stitute to investigate their technical problems. A much more in- 

 telligent and conservative use of silicate of soda has resulted from the 

 Inireau's M^ork. Economy in silicate has been effected and a more 

 tkirable water-resistant board is being made, although the deteriorat- 

 ing effect of silicate of soda on fiber board has not been overcome 

 entirely. 



Factory scale experiments have been made on the use of the ad- 

 hesives from corn cobs, the production of which was described in 

 1919. Commercial mill runs have shown that this adhesive has great 

 value in the production of corrugated and other fiber board. Valu- 

 able results have been obtained and board manufacturers very favor- 

 ably impressed. Laboratory tests have given indications that both^ 

 the"^ corn-cob adhesives and certain kinds of purified concentrated 

 sulphite cellulose liquors are very useful adhesives. 



The results of the investigations upon the examination of enamel 

 ware and upon the use of hydrogenated oils in place of palm oil in 

 the manufacture of tin plate, described last year, have been published 

 this year. Investigations of the suitability of different types of 

 containers for the storage of baking powders and of dehydrated vege- 

 tables and fruits have heen completed and prepared for publication. 



Specifications for the purchase of waterproofing and mildewproof- 

 ing for canvas and of waterproof automobile top dressings have been 

 prepared at the request of the War Department, and samples of 

 waterproofing materials have been, tested and advice given on the 

 award of contracts. By this means the bureau was instrumental 

 in saving the War Department approximately $24,000 on a single 

 requisition and in securing a material much superior to that which it 

 was on tlie point of ordering at about three times the price. Some 

 of the indications from this work are (1) that the oleates of the heavy 

 metals are more toxic than stearates to fungi; (2) that the soaps 

 appear to fall in the following order in their inhibitive effect, 

 barium, magnesium, calcium, strontium, mercury, manganese, lead, 

 iron, cobalt, copper, zinc, nickel, aluminum, and chromium; (3) that 



