odel of Manning Grain Harvester, 1831. USNM 46812; 1906. Model of
horse-drawn reaper measures 16 inches by 8 inches, with a wheel diameter
of 6 inches. Projecting iron points at the front end gather the grain,
and vibrating knives, powered from the hob of the wheel, cut the grain.
Patented by William Manning on May 3, 1831. Gift of United States
Department of the Interior.

16. Model of Boyce Grain Harvester, 1799. USNM 46812; 1906. This model,
made of wood and iron, is 15 inches long, 6 inches wide, and 5-1/2
inches high. Six rotating knives radically positioned on a vertical
shaft rotate by level gearing on the wheel axle. The whole is mounted on
a two-wheeled cart with shafts for draft animals. English patent number
2324 granted to James Boyce in 1799. Gift of United States Department of
the Interior.

17. Model of Newbold Plow, 1797. USNM 46812; 1906. This model of a metal
plow, with wooden beam and handles 14 inches long, represents the plow
patented by Charles Newbold on June 26, 1797, the first American patent
for a cast-iron plow. Moldboard, share, and landside were cast in one
piece. If the plow broke, it became totally useless. Not until the parts
were made in separate pieces did the iron plow come into wide use. The
cast iron broke more readily than did the later wrought-iron plows. Gift
of United States Department of the Interior.

18. Winnowing Basket, about 1750. USNM 54513; 1912. Used by the three
Richardson brothers, the first settlers of Woburn, Massachusetts. The
threshed grain could be winnowed in two ways. It could be poured slowly
from the edge of the basket in a breeze, where the heavier grain fell to
the ground while the chaff blew away. More commonly, the farmer tossed
the grain into the air and caught it in the basket, while the chaff blew
away. This rectangular basket measures 50 inches by 30 inches. Gift of
Mrs. Clarissa W. Samson, West Medford, Massachusetts.

[Illustration: Figure 2.--De Laval centrifugal cream separator of 1879.
(An earlier version of Catalog No. 19.)]

19. Centrifugal Cream Separator, 1914. USNM 56432; 1914. Carl Gustav De
Laval of Sweden invented this successful continuous-flow cream separator
in 1879. Loaned by De Laval Separator Company, New York, New York.

20. Model Tractor, 1919. USNM 64098; 1919. No particular manufacturer
seems represented by this spring-driven toy, which merely represents
tractors of around 1919. The heavy-duty field tractor has four widely