JULY 22, 1871: 30c black (#143), tied by single strike of duplex cancel on folded letter,  dated BOSTON JU 22 MASS., Storer forwarder and "Via San Francisco" on front, HONG KONG SP 2 71 transit on reverse.

30c was the triple rate (10c) payment on an American packet via San Francisco.  The actual 30c rate did not begin until 3/72.

The letter refers to the trans-Atlantic cable with a cost of $1 per word to England  and the riot in New York between Protestants and "Romanists"  on the occasion of the "Orange" Parade.

THE ONLY EXAMPLE OF A TRIPLE RATE
AND THE ONLY OTHER WESTERN ROUTING