The Trans-Pacific steamer service between Hong Kong and San Francisco via Yokohama was operated by the American owned Pacific Mail Steam Ship Company. It commenced in 1867. The treaty between the United States and Great Britain, effective July 1, 1868, established a special rate of 8 Hong Kong cents per half ounce for mail from Hong Kong and Treaty Ports to anywhere in the United States. With the completion of the Trans-Continental Railroad in the United States in 1869, this became the standard route to send mail between the Far East and all parts of USA. Other American and Canadian companies also operated steamers on this route: the Occidental &C Oriental Steam Ship Company from 1875; and the Canadian Pacific Steamship Company between Hong Kong and Vancouver from 1887.

Figure 2:  1872 Manila to Boston cover carried on Trans-Pacific steamer Alaska. Hong Kong adhesives pay treaty rate of 8 cents per halfpence. Russell & Sturgis applied the handstamp "Pr.P.M.S.S.Coy..."

Mail from Manila was sent to Hong Kong to catch the east-bound steamer, and was franked with Hong Kong adhesives, to qualify for the special Treaty rate. Such covers are stamped with Hong Kong and San Francisco circular date-stamps inscribed PAID ALL, as in FIGURE 2. The rate increased to 12 cents per half ounce on April 1, 1877, and reverted to 8 cents per half ounce on April 1, 1879.

The Hong Kong B62 killer cancels the Hong Kong adhesives on every Philippine cover, regardless of route.

The circular date-stamp of Manila appears on just a few covers with Hong Kong adhesives. They are dated between July 18, 1868 and December 9, 1868, and they are all addressed to Britain. However, I know of other covers without the circular date-stamp in the same date range also addressed to Britain. I thus cannot make any definite conclusions as to why the cancellation was applied to some letters but not others.

I know of only two covers with Hong Kong adhesives, sent from towns other than Manila. The first is an 1868 letter from a business firm in lloilo, and has a cachet "STAMPED BY KER & CO MANILA", and a very weak strike of the Manila cds. It is addressed to Edinburgh, Scotland. The second is a letter datelined Vigan July 1, 1870 to Yokohama, which was franked with 14 cents Hong Kong adhesives. It has no Manila markings at all. In Hong Kong, it was marked with a forwarding agent's cancel and a circular date-stamp.

"Singapore" Adhesives 
Singapore used the adhesives of India, until the issuance of adhesives of Straits Settlements in 1867. Consequently, any letter from Manila that first went to Singapore, needed Indian adhesives up until 1867.

In the Indian currency, I anna was divided into 12 pies. In the exchange rate with British currency, 2 annas was equivalent to 3 pence.

The earliest cover from Manila with Indian adhesives is addressed to Sydney, New South Wales, and has a dateline of March 30, 1854. The latest known covers are two 1867 letters to Switzerland each franked with 13 annas 4 pies. The later of these is dated June 17.

Straits Settlements adhesives were issued on September 1, 1867. From this date, any letters from the Philippines passing through Singapore were franked with Straits Settlements stamps. I know of two Philippine letters sent in 1867, bearing these adhesives with the crown overprint. Both are to the same correspondent in Switzerland.

All other Philippine letters with Straits adhesives were sent between 1872 and 1877. Most were addressed to European destinations, particularly France. On the other hand, 1872 is the latest date we know for a letter with Hong Kong adhesives to Europe. The explanation is that 1872 was the start of the regular mail steamer service between Manila and Singapore.

Many of the letters were carried from Singapore by French steam packets. The major French port was Saigon, situated between Hong Kong and Singapore. It was thus easier for Manila to predict the departure date of the French steamer from Singapore than from Hong Kong. Furthermore, French steamers landed at Marseilles, which was convenient for mail addressed to France, while from late 1870, the P&0 steamers landed their mail at Brindisi in Italy.

Acknowledgment
My sincerely thanks to Dr. Geoffrey Lewis, a good friend of mine and a fellow member of the Society of Postal Historians for sharing his research with us. Dr Lewis has written the book "Postal History of the Spanish Philippines, 1565 - 1898" with co-author Don Peterson. The book is the first ever on this subject. The emphasis is on routes and rates, so the book will be a useful reference for any collector of maritime postal history of 19th century Asia, Dr Lewis won the Grand Prix at the 1996 Taipei FIAP Exhibition for his collection of Philippines Postal History.

The book was published in December 2000, and the cost of US$95.00 includes surface postage from USA.  Further details at www. custom-made.com.au/book.htm or from Dr Geoffrey Lewis, email glewis@custom-made,auoratP,O.Boxl96, Randwick NSW 2031, Australia.