The tone of Jane's letter is both gleeful and confident as she reports the news of Frank's promotion to Commander and her pen happily flows on to news of Charles...

The enthusiasm shown in Letter 16 reminded me of her words from 1791;
'It was about this time that Sir Francis Drake,the first English Navigator who sailed around the World...Yet great as he was, and justley celebrated as a sailor, I cannot help forseeing that he will be equalled in this or the next Century by one who tho' now but young, already promises to answer all the ardent and sanguine expectations of his Relations and Freinds...'

JA, 'History of England'.

Years after JA's death Sir Francis Austen lived up to his sister's youthful expectations to became Lord Admiral of the Fleet.
Charles also became an Admiral.
Jane was right to be proud of her navy brothers. If only she'd seen their greater success !

And how happy she'd be for close family friend Martha Lloyd who married Francis... now I'm jumping far ahead !