Mural

<spoiler> Hint: "People and dates with lasting effect."

The initials on the mural correspond to the names of the inventors, most of whose whose inventions depicted:

• EW = Eli Whitney invented the cotton gin 1794
• HD = Humphrey Davy - Demonstrated electric lamp to the Royal Society - 1806
• JW = John Whitehurst - Pulsation Engine (hydraulic pump) - 1722 other possible answer James Watt - Improved steam engine - 1763
• BF = Benjamin Franklin - Pointed light rod conductor - 1752
• GLL = George Louis Lesage - Used a single wire system to telegraph a message - 1774
• LP = Louis pasteur - Process of sterilizing milk - 1862
• GS - George Stephenson - Locomotive - 1814
• GM = Guglielmo Marconi - Radio - 1901

*AGB = Alexander Graham Bell - Phonophone (or more commonly, the telephone) - 1880

• CM = Cyrus McCormick - Inventor the Reaper - 1809
• TE = Thomas Edison - Invented phonograph - 1877

The San Francisco picture shows 3 items above the same starburst(?) pattern: A locomotive (invented by George Stevenson/GS), a telephone (invented by Alexander Graham Bell/AGB); both represented in the mural. The only one not represented is the statue of Poseidon, whose son is TRITON.

The accepted answer is: triton

</spoiler>

Next book: Tomb