<P> By the late 19th century, most American states had outlawed wife beating; some had severe penalties such as forty lashes or imprisonment for offenders . There was a common belief in parts of the United States that a man was permitted to beat his wife with a stick no wider than his thumb; however, this belief was not connected with the phrase rule of thumb until the 1970s . </P> <P> In the 20th century, public concern with the problem of domestic violence declined at first, and then re-emerged in the 1970s along with the resurgent feminist movement . The first recorded link between wife beating and the phrase rule of thumb appeared in 1976, in a report on domestic violence by women's - rights advocate Del Martin: </P> <P> For instance, the common - law doctrine had been modified to allow the husband' the right to whip his wife, provided that he used a switch no bigger than his thumb'--a rule of thumb, so to speak . </P> <P> While Martin appears to have meant the phrase rule of thumb only as a figure of speech, some feminist writers treated it as a literal reference to an earlier law . The following year, a book on battered women stated: </P>

Where did the saying rule of thumb originate