Collective Nouns

Think you know your collective nouns well?

How about the following:

• A ledger of accountants
• A billow of winds
• A balance of bookkeepers
• A resolution of mediators
• A galaxy of astronomers
• A last of cobblers
• An extraction of dentists
• A trawl of fishermen
• A gaggle of telephones

And my favourite: 

• A wish of ghosts