Authors:

You will observe with concern how long a useful truth may be known, and exist, before it is generally received and practiced on.

Benjamin Franklin, Jared Sparks (1882). “The Works of Benjamin Franklin, Containing Several Political and Historical Tracts Not Included in Any Former Edition, and Many Letters Official and Private Not Hitherto Published”
You will observe with concern how long a useful truth may be known, and exist, before it is generally received and practiced on.