what is the historical origin of the cable tow in craft masonry and how do preston and mackey explain its symbolic meaning

The provided sources do not detail the historical origin of the cable tow prior to its traditional usage, nor do they contain the specific explanations of William Preston or Albert Mackey.

What the library does record regarding the cable tow's length and symbolic meaning comes from later commentators and jurisdictional decisions. Traditionally, the length of a cable tow was considered to be three miles, serving as the distance within which a Mason was expected to answer a lodge summons 1. This physical measurement was formally redefined at the Baltimore Masonic Convention of 1843 as "the scope of a brother's reasonable ability," leaving each Mason to determine what is just and reasonable according to his circumstances 1.

In terms of symbolic interpretation, Walter Leslie Wilmshurst reads the cable tow as an emblem of irrevocable spiritual bound. He considers the cable tow around the neck to signify that once a candidate is moved by a genuine desire for hidden knowledge, he cannot retreat from what he learns without committing moral suicide 2.