Heat oven to 375°F.
Sift together 1/2 cup sugar, the flour and salt into a bowl.
Beat whites, cream of tartar and cherry extract in bowl on high speed until soft peaks form. Gradually sprinkling sugar over whites, 1/4 cup at a time, beat in remaining sugar until stiff peaks form. Sift flour mixture over whites, about a quarter of it at a time; gently fold in with rubber spatula, using about 15 strokes with each sifting.
Turn third of batter into second bowl; gently fold in cherry pie liquid.
Alternately spoon batters, beginning with white batter, into 10-inch tube pan with removable bottom. Cut through batters to marbleize.
Bake in 375°F oven 30 to 35 minutes, until tester inserted halfway between tube and side of pan comes out clean. Invert pan onto bottle; let cool 1 hour.
Run thin metal spatula around sides of pan and tube. Turn cake out onto rack; invert. Let cool. Store in container with tight-fitting lid.