progressive" and considering Elizabeth Hayward's Progressive ideals, and specifically her interest in protecting the rights of children as well as her strong support of President Woodrow Wilson, the most likely answer to my question about what her "10%" button meant is the following.
In 1919 President Woodrow Wilson signed the Child Labor Tax Law.
The Child Labor Tax Law is title No. XII of an act entitled 'An act to provide revenue and for other purposes,' approved February 24, 1919.... The heading of the title is 'Tax on Employment of Child Labor.' It begins with section 1200 and includes eight sections. Section 1200 is as follows:
'Sec. 1200. That every person (other than a bona fide boys' or girls' canning club recognized by the agricultural department of a state and of the United States) operating (a) any mine or quarry situated in the United States in which children under the age of sixteen years have been employed or permitted to work during any portion of the taxable year; or (b) any mill, cannery, workshop, factory, or manufacturing establishment situated in the United States in which children under the age of fourteen years have been employed or permitted to work, or children between the ages of fourteen and sixteen have been employed or permitted to work more than eight hours in any day or more than six days in any week, or after the hour of seven o'clock post meridian, or before the hour of six o'clock ante meridian, during any portion of the taxable year, shall pay for each taxable year, in addition to all other taxes imposed by law, an excise tax equivalent to 10 per centum of the entire net profits received or accrued for such year from the sale or disposition of the product of such mine, quarry, mill, cannery, workship, factory, or manufacturing establishment.' (Bailey v. Drexel Furniture Co., 259 U.S. 20 (1922))
Basically, this act was an attempt to regulate and discourage child labor by instituting a ten percent tax on the net profits of business that employed children younger than fourteen or had them working more than eight hours a day, six days a week.
This tax was found unconstitutional in 1922 by the U.S. Supreme Court in the act quoted above, Bailey v. Drexel Furniture Company.
The photo is from Wikipedia and was taken by Lewis W. Hine in 1910. The subject is "Rose Biodo, 1216 Annan St., Philadelphia. 10 years old. Working 3 summers. Minds baby and carries berries, two pecks at a time. Whites Bog, Brown Mills, N.J. This is the fourth week of school and the people here expect to remain two weeks more. Witness E. F. Brown. Location: Browns Mills, New Jersey."