Mahlon Pitney, Eagle Glass Mfg Company v. Rowe…
“ If at any time while I am employed by the Hitchman Coal & Coke Company I want to become connected with the United Mine Workers of America, or any affiliated organization, I agree* to withdraw from the employment of said company, and agree that while I am in the employ of that company that I will not make any efforts amongst its employes to bring about the unionizing of that mine against the company's wish. ”
