21. Model Tractor with Plow, Harrow, and Roller, 1919. USNM 64098; 1919. Spring-driven, toy tractor. The plow, harrow, and roller, as well as the tractor itself, represent a typical machine of the period. The product of no particular firm seems to have been copied. Gift of Toy Manufacturers of the United States, New York, New York. 22. Meat Grinding Machine, about 1810. USNM 110326; 1930. Hand made of wood and iron, with six parts held together by two iron bolts. The cutting edges are set in the sides of a box parallel to each other and about one-quarter inch apart. A shaft, set in the center of the box, is turned by a crank. The horizontal shaft has iron slugs, graduated from coarse to fine, set into the shaft in a helical pattern. The meat enters through the square hole at the top and the iron teeth press it against the knife edges; thus, the meat is cut smaller and smaller until it comes out a small hole in the bottom of the machine. The device is very ancient in design and could still be found in common use in the United States as late as 1860. Gift of R. C. Fairhead, Rushville, Nebraska. 23. Carey Plow, about 1815. Received from Division of Ethnology in 1931. A Carey plow with a slot in the beam for a colter. The landside handle passes through the beam. Usually, the beam tenon passes through a mortise in the handle. Possibly made by the farmer. Replication of a common and popular American plow of the 18th century. Donor not known. 24. Hoe, about 1830. USNM 115122; 1931. Wrought-iron, handmade hoe made in Ohio and attributed to very early 19th century. The hoe's blade is 5 inches wide and its handle is 6 feet long. Gift of Mrs. Grace M. Swiggett, Washington, D. C. 25. Reaper Sickle Bar, about 1847. USNM 115878; 1931. Sickle bar from a McCormick reaper. The blade style suggests a comparatively sophisticated stage of development, most surely after 1833. David Cromer of Seneca County, Ohio, used this sickle bar on a McCormick reaper. The blade is 5 feet long and 5 inches deep. Gift of Frank Hepp, Berwick, Ohio. [Illustration: Figure 3.--Gail Borden's vacuum pan of 1853, used to make condensed milk. (Catalog No. 26.)] 26. Borden Vacuum Pan, 1853. USNM 119188; 1932. The original vacuum pan used by Gail Borden in 1853 for condensing milk by concentrating it in a vacuum. He patented the process on August 19, 1856. Borden borrowed this pan from nearby Shaker farmers who had used it for canning. Borden did his early work at New Lebanon, New York. Borden at first failed to get a patent because the process was not deemed useful. There is nothing exceptional about this pan except that Borden used it. Gift of Borden Milk Company, New York, New York. 27. Model of McCormick Reaper, 1834. USNM 121105; 1932. Scale model of the grain reaper patented by Cyrus McCormick on June 21, 1834. Roderick Davis constructed the model from the specifications of the patent. Gift of Charles G. Abbot, Washington, D. C.