MHH 15

            Plate 15

         A Memorable Fancy

   I was in a Printing house in Hell & saw the 
method in which
knowledge is transmitted from generation to 
generation.
   In the first chamber was a Dragon-Man, 
clearing away the
rubbish from a caves mouth; within, a 
number of Dragons were hollowing the  cave, 
  In the second chamber was a Viper folding round 
the rock & the 
cave, and others adorning it with gold silver and 
precious stones.
   In the third chamber was an Eagle with 
wings and feathers of air, 
he caused the inside of the cave to be 
infinite, around were
numbers  of Eagle like men, who built palaces in the immense cliffs.
   In the fourth chamber were Lions of flaming fire raging around
&  melting the metals into living fluids.
   In the fifth chamber were Unnam'd forms, which cast the metals 
into the expanse.
   There they were reciev'd by Men who occupied the sixth
chamber,  and took the forms of books & were arranged in
libraries.
         ____________________________________________________

Blake's printing house in hell: Look at this comment:
"The juxtaposition of printmaker and poet in Blake's illustrations takes the systematized process of
engraving, whose end result produces art." from (William Blake's Reception.)  'Hell' at this point signifies Blake's studio.

His 'six chambers' are reminescent of the four zoas, listed as follows:
bull Luvah
lion Urizen
eagle Tharmas
man  Urthona
(See Fearful Symmetry p.277)

MHH might be considered a source of the development of The Four Zoas, but in the Unholy Bible a detailed discussion of the caverns of the Cave begins with  Cecrops of Greek Mythology who was half man and half (in the lower half) dragon.  Blake was probably familiar with that myth. 

The rubbish the dragon-man cleared away, Singer says, is the 'debris of materialism' that prevents man from having any interest in anything else.

The viper (or snake) is Satan who tempts man with all sorts of beauty such as gold and siver and precious stones; he is the "cherub with the flaming sword" that keeps us out of Eden.
Ezekiel 28:16:
"16 By the multitude of thy merchandise they have filled the midst of thee with violence, and thou hast sinned: therefore I will cast thee as profane out of the mountain of God: and I will destroy thee, O covering cherub, from the midst of the stones of fire."

In the third chamber the eagle expands the cave to Infinity. The eagle is the polar opposite to the viper. Notice the picture of the eagle,especially the color.

The lions in the fourth chamber are equivalent to Blake's furnaces:

The 'cave' might be considered a commentary on Plato's 'cave'.

Here are two earlier posts on this subject:
The Printing House Printing House II