June 1, 1881
Appointment to fill the vacancy created by the resignation of BOE Member Moses M. Drew (SBOE-02) following his appointment as U.S. Marshal for the District of California.
DATE IS UNCERTAIN.
According to a document by the SBOE [link], "Moses Drew assumed office in January 1880 and resigned soon after, with William Johnston being appointed to the position by Governor Perkins to replace Drew." However, Drew did not become U.S. Marshall until 1882 and Johnston was the Senate President pro Tempore in 1881. Most likely, the resignation occured after the end of the 1881 legislative session which ended in May.