Herdson also discusses how toconvert numbers and letters into such uninspiring mental pictures as a candle, a foot, a pipe, and similarhousehold items.
What relation does Henry Herdson's The Art of Memory Made Plaine (1651, 1654) have to the potential development of the major system. The description here sounds like it's relatively similar. Who/What were his precursors, and who may have been influenced by his version of this system which sounds very similar.