On May 5, 1904, the cornerstone of the new Capitol was laid by Governor Samuel W. Pennypacker. Architect Joseph M. Huston induced the Capitol Building Commission to have a stone laid on the corner of the center wing just to the right of the main entrance portico.

The cornerstone ceremony was the highlight of the Capitol construction in the spring of 1904. Unlike the groundbreaking, which had been almost a private ceremony, the cornerstone laying drew a large crowd. Governor Pennypacker, the eight members of the Capitol Building Commission, architect Huston, and construction contractor George F. Payne all participated.

The Governor headed a small procession to the palm-decorated stand, where the cornerstone laying occurred. With him were his private secretary and the contractor's men carrying the metal memorial box, which he had kept in his private office until the time for the ceremony arrived.

Newspaper accounts of the event vary. One reported that several short speeches were delivered; another reported that there was no speechmaking. Whatever the case, the ceremony was a very simple affair that lasted only about ten minutes. It consisted merely of the placing of the box in the hollow stone by architect Joseph Huston and contractor George F. Payne and the laying of a bed of cement for the capstone by Governor Pennypacker. After the box had been placed in the stone, architect Huston handed the Governor a silver trowel with an ebony handle and the Governor started to heap mortar on the box that was covered with a canvas wrapper tied with violet ribbon.

The silver trowel used by the Governor bore the following inscription on the blade: This trowel was used by Governor Samuel W. Pennypacker to lay the memorial box in the cornerstone of the Capitol building at Pennsylvania, May 5, 1904. Architect, Joseph M. Huston. Contractors, George F. Payne & Co.

Architect Huston corrected Governor Pennypacker's technique and then Huston laid aside his silk hat and proceeded to spread the mortar for him. Once this task was properly completed, Payne directed the steam crane which swung and lowered the two and one-half ton capstone into place. Proudly floating on the cable of the steam crane was a new American flag. The application of the capstone was completed by the firm of Charles H. Parson, the granite setters.

The memorial box was covered on all sides with inscriptions, giving the names of the members of the Capitol Commission, the architect and contractor, the heads of the state departments, senators and members of Congress from Pennsylvania.