Simona Cohen in "The early Renaissance personification of Time", p 311.:
Figure 6 (in the article) should be ...
I don't discover the hour-glass clearly, but likely it's on the back of the hermit
Figure 7 should be ....
hour-glass on the chariot
Figure 8 should be ....
... already noted in this thread, given to 1459
Figure 9 (hermit with mechanical clock) should be ...
... which is the same as from the list of Michael J. Hurst. The two men are time-counters (?) ...just my speculation. The read putti on the chariot looks a little bit like the figure of the world at the d'Este cards.
Cohen notes a 100 years earlier Temperance with hour glass, which should be this one ...
http://en.wikipedia.org/wiki/File:Ambro ... erance.jpg
... by Ambrogio Lorenzetti.
Compare: http://www.shafe.co.uk/art/Ambrogio_Lor ... -_Nove.asp
and: http://www.shafe.co.uk/crystal/images/l ... 1338-9.jpg
Later, as Cohen notes, the hour glass is given to Father Time (with the idea of a finishing death), and the mechanical clock (with th idea of steadiness) becomes a symbol of Temperance.
In matters of the Tarot sequence in the Western order we have, that 14 Temperance follows 13 Death and the Hermit is "before Death) ... maybe the idea, that the steadiness of time overcomes "individual death".
As a summary: if the Pierpont-Morgan-Bergamo Hermit is really from 1450-1452, it would be rather early for this motif.
Cohen adds a third hermit picture "before 1450" with globe similar object ("globe, armillary sphere, elements") It's not included in Michael's collection: