Ceylon: WWII Air Mail Letter Card to Canada

Military Air Mail Letter Card sent from Ceylon (R.A.F. Base P.O, no date) to Toronto, Canada.
This letter was sent via Lagos, Nigeria, to the US and Canada.

Single-ring instructional handstamp “Canada and U.S.A. only”, presumably added by the R.A.F. Base P.O in Colombo to allow for easier sorting at the Lagos intermediate stop.

Required postage was 75 cent (Ceylon) or 25 cent (Canadian), so overpaid by 3 cent.

Ceylon: 80c Lioncel Aerogramme Issued 1971

The rare last aerogramme of Ceylon (80c Lioncel with "Ceylon for Quality Teas" imprint, Wiegand #29), issued in 1971. Used in 1973, i.e. after the Republic of Sri Lanka was established in May 1972.

Ceylon: Late Usage of OHMS Aerogramme

O.H.M.S. aerogramme form sent from Royal Botanic Gardens at Peradeniya (22. 2. 72) to France with red „Colombo Official Paid“ circular handstamp of 23 FE 72.

Very thin paper, IMPERIAL AIR MAIL watermark, year code „E“ below „AIR MAIL“ for 1971.

Late usage of a Ceylon O.H.M.S. aerogramme as Ceylon became a republic under the name of Sri Lanka in May 1972.

Ceylon: Short Paid Aerogramme to Canada 1959

Ceylon 40 cents aerogramme uprated with a 10 cents stamp and sent from Kandy (9 11 59) to Vancouver, Canada.

The aerogramme was taxed 13 UPU ctms short paid and attracted a 4 cents postage due in Canada.
At the time of posting, the aerogramme rate to Canada was 60 cents. Double the deficiency (20 cents) was converted to UPU ctms at 10 cents = 6.5 UPU ctms.

Upon arrival in Canada, the 4 cents postage due was calculated based on a conversion rate of 1 cent = 3 UPU ctms.

Boxed “4 cents due” handstamp in red and a 4 cents postage due stamp added.

Ceylon: 1971 O.H.M.S. Aerogramme Form

O.H.M.S. aerogramme form sent from Colombo (22. 2. 71) to India with red „Colombo Official Paid“ circular handstamp of 25 FE 71.

Very thin paper, IMPERIAL AIR MAIL watermark, year code „A“ below  „AIR MAIL“ for 1967.

Ceylon: 50c Lioncel Issue

This is Wiegand #26, the 50c Lioncell issue of 1966, commercially used in 1969 to Pakistan. Only a small number of this aerogramme was printed. Much more were sold of the 1969 issue, which has the "Ceylon for Quality Teas" cachet in the lower left corner of the front panel.


Reference
Wiegand, Katalog der Aerogramme von Asien, 2000

Ceylon: Short-Paid Aerogramme

Ceylon 50 c aerogramme (Wiegand #27), issued in 1969, used after independence in 1973, when the aerogramme rate was 90 c. Consequently the aerogramme was taxed as short paid. "80" in the tax fraction's numerator stands for double the deficiency, "60" in the denominator for the first weight step international letter rate. 

The international letter rate in the US in 1973 was 15 ct, so multiplying the tax fraction with this rate results in the 20 ct postage due, which was endorsed in the boxed postrage due handstamp.

Ceylon: Short-paid Aerogramme Diverted to Surface Mail

Ceylon air letter (Wiegand #9 - grey paper, no watermark, “Fold here …” on sealing flap is 63.0 mm wide - subtype not mentioned in Wiegand catalogue) sent from MOUNT LAVINIA (25 JU 56) to Newark, US

Two-line red instruction handstamp “ INSUFFICIENTLY PAID FOR / _____ AIR SERVICE”. The aerogramme was not taxed as short paid (the “T” handstamp was crossed out)

The aerogramme rate to the US was 50 ct, so less than half of the rate was prepaid. Hence, most likely, the aerogramme travelled by surface mail to the US.


Reference
Wiegand, Katalog der Aerogramme von Asien, 2000

Ceylon: Postage Due Aerogramme

Ceylon air letter (Wiegand #12a - white paper, no watermark, “Fold here …” on sealing flap is 58.0 mm wide) sent from JAFFNA (10 MY 55) to Tours, France.

Postage due calculation in the country of origin
The 20 ct aerogramme was taxed as short paid, because the aerogramme rate to France was 40 ct. So double the deficiency (40 ct) was postage due. The standard conversion rate should have been 20 UPU ctms = 35 ct (1 ct = 0.8 UPU ctms). Ceylon made use of the opt-out clause, which was agreed upon at the 1952 Brussels UPU congress, and calculated with, roughly, a 15% reduction in letter rates: 1 ct = 0.68 UPU ctms, so 20 UPU ctms ≈ 30 ct.

Postage due calculation in the country of destination
In France the standard conversion rate should have been 30 f = 20 UPU ctms 
(1 f = ⅔ UPU cmts). However, also the French postal authorities made use of the opt-out clause converting 27 UPU cmts into 31 f (1 f = 0.871 UPU ctms leading to 20 UPU ctms ≈ 23 f), equivalent to roughly a 20 % decrease in letter rate, Four postage due stamps with a total face value of 31 f document that the postage due has been paid.


Reference:
Wiegand, Katalog der Aerogramme von Asien, 2000

Ceylon: Short Paid Aerogramme to the UK

Aerogramme sent from Colombo (25 NO 59) to London, UK. The aerogramme was pre-paid 40 c, which is 10 c short of the 50 c aerogramme rate. Circular “T centimes” handstamp (endorsed “13”) applied at Colombo. Upon arrival in the UK, a “3 ½ d TO PAY F.S.” handstamp in green was applied. Two postage due stamps with a total face value of 3 ½ d were affixed, documenting that the postage due was collected from the consignee.

Postage due calculation in country of origin

The 1957 Ottawa UPU congress (effective April 1, 1959) fixed the foreign letter rate at 25 UPU centimes (ctms). Member countries, however, were allowed to increase their letter rate by up to 60 % or decrease it by up to 20 %. Ceylon was one of the countries where the foreign letter rate differed from the 25 UPU ctms standard.

The foreign letter rate was 35 c. Assuming that this rate was equal to 25 UPU cmts, double the deficiency (20 c) would have equaled 14.3 UPU cmts. As only 13 UPU ctms were endorsed the exchange rate must have been different, i.e. Ceylon’s foreign letter rate was set below the UPU standard.

Starting, as endorsed, with an exchange rate of 20 c = 13 UPU ctms (or 1 c = 0.65 UPU cmts, a straight forward calculation shows that the correct exchange value of 25 UPU ctms must have been about 38.5 c, which means that Ceylon had set its letter rate 10 % below UPU standard.

Postage due calculation in country of destination

Since 1943, the British postal authorities ignored any postage due markings in UPU cmts on incoming international mail. According to Michael Furfie,

"The British Form P114 included only rates to Britain, so in cases where the
letter rate to Britain was less than the country's UPU rate, postage due
calculation could not have used the relationship

Country's UPU rate = Britain's UPU rate

because offices of exchange using the form would not have known the first of
these.

Although I've never found any official explanations of how it was done, I
believe that, for the most part, the equivalent of the letter rate to
Britain was calculated at PO HQ (which would have had all the information)
as

Country's rate to Britain x Britain's UPU rate / Country's UPU rate

and rounded to the nearest halfpenny. If Ceylon's rates were 25 cents to
Britain, 35 cents UPU, then the equivalent of this 25 cents would have been
25 x 6d / 35 cents = 4.29d, rounded to 4½d. The relationship 25 cents = 4½d
would then have been used to convert double the deficiency into pence: 20
cents x 4½d / 25 cents = 3.6d, rounded to 3½d.

Unfortunately, no copies of Form P114 seem to have survived from between
late 1957, when the 6d rate was introduced, and 1966, when taxe fractions
replaced gold centimes, so we can't be absolutely sure. No equivalence of 25
cents other than 4½d gives 20 cents = 3½d, though."

Credits
Thank you, Allan, for establishing contact to Michael - and most of all thank you Michael for sharing your expertise. 

Ceylon
Postage Due

The 35c aerogramme above (Wiegand no. 6, i.e. no watermark and "Fold here - Do not write on reverse of this flap" on the top sealing flap is 53.5 mm wide) was sent from TELLIPALLAI (today Tellippalai, cds 22 JL. 49), to New York, USA.

The postage rate was 50c, so the aerogramme was shortpaid 15c. The Ceylonese postal authorities converted double the deficient postage (30c) into UPU gold centimes at an exchange rate of 1c = 0.8 centimes, which resulted in a postage due of 24 ctms as it was endorsed in manuscript at the right hand side of the FTS taxation stamp. "FTS" stands for "Tax - Foreign Service".

The U.S. postal authorties converted the amount postage due into 8c U.S. currency at an exchange rate of 1 U.S. cent = 3 UPU gold centimes and affixed 5c and 3c postage stamps accordingly.

Below is a 35c aerogramme (Wiegand no. 7f, yellowish paper, watermark "TITAN BOND", "Fold here - Do not write on reverse of this flap" on the top sealing flap is 64 mm wide) posted from COLOMBO (cds 24. SE 48) to Holland, Michigan/USA, duly uprated with a 15c stamp to meet the 50c postage rate.

References
Wiegand stands for Wiegand, Katalog der Aerogramme von Asien, 2000