Here is an iron for the annals of history. Heel-and-toe weighting was tried in scant few clubs during the wood shaft era, and this is one of them. Marked "john D Dunn" on the raised "toe weight" and "Winton, London" etc on the back of the blade, this mashie still has its original 37" shaft and leather wrapped grip.  

A descendant of Willie Dunn Sr, John Duncan Dunn was an important and well-known character and clubmaker in the world of golf. During the 1890s and early 1900s, "John D. Dunn" and "Dunn" applied for no less than 8 patents (that were not issued for whatever reason).  Both he and his brother William were innovators. After immigrating to America, John later served briefly as the professional at the Los Angles Country Club.