Icebox Pickles

1 gallon cucumber slices
4 to 5 onions
1/4 cup salt
4 cups granulated sugar
4 cups vinegar
1 1/2 teaspoons celery seed
1 1/2 teaspoons mustard seed
1 1/2 teaspoons turmeric

Allow cucumber slices, onions and salt to set for 1 hour; drain. Heat (do not boil) sugar, vinegar, celery seed, mustard seed and turmeric. Pour over cucumbers. Cool, then refrigerate.