If long columns of beads must be used as in Fig. 201 for New York and Boston, the beads may be strung on piano wire such as may be secured in any good hardware store. The piano wire should be heated in a gas flame so as to remove some of the spring temper. After the wire has been heated it can be straightened and it will remain straight without continually springing back into coil form.

252 GRAPHIC METHODS

Brass wire should be used if the holes in the beads are large enough to take wire of a diameter sufficient to give the required amount of stiffness. Brass wire is not as stiff as steel wire. When small beads must be used having small holes, the combination of wire and beads may be given several coats of varnish, if necessary, to make a tall bead column stand up straight. The columns for Boston and New York in Fig. 201 had to be varnished as the wire was very small on account of the fact that the diameter of the beads was only about -i^ inch.

The bead map in Fig. 201 gives a great quantity of information in a small amount of space. The illustration depicts the whole United States on a page width of only 5}/^ inches, yet all the facts represented by the beads are brought out clearly. The men of the group portrayed who reside in foreign countries are indicated by pins near the seacoast with arrows pointing toward the country of residence. The fact that there were large numbers of the men in Massachusetts made necessary an extremely long wire for the beads of the Boston district. Because of the small size of the finished illustration and the size of map available, large diameter beads could not be used, and the bead wire for the Boston district was necessarily very tall and slender.