1

So.. what does the line "Shower it on the Admiralty" means?

2

There is kind of a labored joke, and I'm not sure I get it all.

He's complaining that the government isn't making or letting the Navy do as much as he thinks it should be doing, e.g. preventing the Germans from making an amphibious landing south of Reval, now Tallinn in Estonia, then part of the Russian Empire.

He says, jokingly, that he hears that a new order of knighthood is being considered (on the tapis = on the table, under consideration; tapis = carpet or tablecloth), the OMG (comparable perhaps to the OM, Order of Merit, or OBE, Order of the British Empire), which he explains as meaning Oh My God, and suggests that lots of them should be awarded to the naval command ("Shower it on the Admiralty.") I guess the idea is that everyone in the admiralty will be exclaiming Oh My God! at the thickheadness of the government in not putting them properly to work.

So he isn't actually using OMG as an exclamation and then explaining it, as the writer seems to think.

3

By the way, the bit of verse he quotes is from Alexander Pope's Eloisa to Abelard. charlie Kaufman used the next line as a movie title:

How happy is the blameless vestal's lot!
The world forgetting, by the world forgot.
Eternal sunshine of the spotless mind!
Each pray'r accepted, and each wish resign'd.

4

wow, thank you Vinny.
Thought we would all find it interesting (should we understand that question.. hehe)

5

It helps to undersand this pleasantry if one realises that there are existing honours, mostly reserved for senior civil servants (who could have got larger salaries in private business), with jocular interpretations as follows:
CMG - Commander of St Michael & St George, jocularly "Call Me God"
KCMG - Knight Commander of St Michael & St George, jocularly "Kindly Call Me God"
GCMG - Grand Commander of St Michael & St George, jocularly "God Calls Me God"