And it seems he changed "My sons ought to study Mathematicks and Philosophy, Geography, natural History, Naval Architecture, navigation, Commerce and Agriculture, in order to give theirs a right to study Painting, Poetry, Musick, Architecture, Statuary, Tapestry and Porcelaine." to "in order to give their Children a right" to include women in that third generation.
Ah! I was wondering what that change signified. I assumed it was just a corrected mistake, but you're right, it changes the gender of the third generation. Very interesting.
I think I can picture him, writing "...give their sons a right to study Painting, Poetry, Musick, Architecture, Statuary,... hmm, Tapestry... and Porcelaine? Let's make it 'children'!" ツ