34 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1919. 
yams with examples of pattern stitches, an extensive collection illus- 
trating the production, classification, and conservation of foods, with 
many such from the Department of Agriculture and the United States 
Food Administration, and an exhibit illustrative of neglected sources 
of supply of fats and oils for food purposes. 
In making the food exhibits as useful as possible a cooperative ar- 
rangement was entered into with the States Eelations Service of the 
Department of Agriculture whereby regular demonstrations on the 
value, use, preparation, and conservation of foods were given at the 
Museum by experts of the department. A large room in the arts 
and industries building was fitted up as a demonstration kitchen and 
space provided for displaying foods, models, and household equip- 
ment. This work soon broadened into a household consultation cen- 
ter, with lectures and demonstrations covering a wide range of sub- 
jects. There were lectures on the Business of the household; Food 
for the family on $2 per day; Direct marketing; ^Vhat becomes of 
the consumer's dollar; What to give your children to eat; Milk, its 
nutrition and use; Meat substitutes; Housekeeper's use of market 
schedules; and Influence of weave structure upon the durability of 
fabrics. The demonstrations included labor-saving appliances for 
the kitchen ; the fireless cooker ; the pressure cooker ; the electric wash- 
ing machine ; preserving eggs ; cooking dinner in 30 minutes ; the one- 
dish meal; invalid cookery; dried milk powder; Christmas sweets; 
sugarless candies ; and fruit juices in summer drinks. By classes and 
demonstrations for housekeepers in the mornings and afternoons and 
special classes for war workers at 5 p. m., over 2,100 persons were 
reached during the year. 
Mineral technology. — In mineral technology the customary work 
of the division was shelved in favor of special activities with a more 
direct bearing on the national emergency. As the war progressed 
the call for specialization on the part of its technical staff increased. 
While the country was still actively involved on a basis of war, 
scarcely a day passed without bringing calls from some governmental 
agency for assistance with reference to one or another industrial 
issue up for consideration on an emergency rating, the questions 
ranging from determining a fair price for mica to determining the 
likelihood of a paralyzing petroleum shortage. As the year ad- 
vanced, however, two absorbing lines of special investigation de- 
veloped to such a degree that during the latter half of the year the}'' 
largely engrossed the attention of the staff. Their general nature 
may be gathered from the titles under which the results were issued. 
One, "A Report on the Political and Commercial Control of the 
Nitrogen Resources of the World," represents an effort to unravel 
the complexities of the nitrogen situation left behind in the passing 
