Explain every line of this paragraph from chapter 15

 

yonder were the lagoons Venice, where we sailed every evening when the city and fountains were illuminated. I also went on board on a Viking ship which lay a short distance from the little craft. I had been on a man-of-war before, in Boston, and it interested me to see, on this Viking ship, how the seaman was once all in all - how he sailed and took storm and calm alike with undaunted heart, and gave chase to whomsover reechoed his cry, "we are of the sea!" and fought with brains and sinews, self-reliant, self-sufficient, instead of being thrust into background by unintelligent machinery, as Jack is to-day. So it always is-"man only is interesting to man"