| watt (W) | 
| James Watt (1736–1819) |
|---|
| watt (W) |
| James Watt (1736–1819) |
|---|
James Watt was a Scottish instrument maker and inventor. During his work which led to the invention of the steam engine, he learned much about the properties of water vapour and steam, and independently discovered that a latent heat of vaporization is associated with the change of phase of water from liquid to gas. He also tabulated the vapour pressure of water as a function of temperature before the work of Clapeyron. Both these concepts are important in meteorology.
In the late 1700s, Erasmus Darwin, Matthew Boulton, Josiah Wedgwood, Joseph Priestley and Watt formed the Lunar Society. It was an informal group of friends that met to discuss the latest topics in chemistry, mineralogy, meteorology, astronomy and physics.
To honour his scientific work, Watt's name was given to the SI (International System of Units) unit of power. One watt is equal to one joule per second.
| Country | Catalog Number | Type of Item | Year of Issue | Notes on Content |
|---|---|---|---|---|
| Albania | 2205c (Mi2294) | One of strip of 4 (2205 (a-d)) (Mi2292-2295) | 1986 | (250th anniv. birth) |
| Albania | 2205a-d fdc | One of four stamps on FDC | ||
| Albania | 2206 (BL87) | On (center) label of SS1 | ||
| Antigua and Barbuda | 1605B (Mi1671) | 1992 | "James Watt" | |
| Barbuda | 1367 (Mi1476) | Antigua and Barbuda 1605B overprinted "Barbuda Mail" | 1993 | "James Watt" |
| Bosnia and Herzegovina (Serb Admin.) | 126e (Mi189) | One of booklet pane of 7 (126 (a-g + 2 labels)) (Mi185-191) | 2000 | (180th anniv. death, in 1999) |
| Burundi | 1245b (Mi2869) i1245b | One of MS4 (1245 (a-d)) (Mi2868-2871) One of imperforate MS4 (i1245 (a-d)) | 2012 | "James Watt" |
| Chad | Unknown c (Mi?) Unknown ic | One of MS4 (a-d) One of imperforate MS4 (a-d) | 2015 | "James Watt"; (280th anniv. birth, in 2016) |
| China (People's Republic) | None | Postal card back1, also front | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1 (different), also front (same) | 2009 | (190th anniv. death) |
| China (People's Republic) | None | Postal card back1, also front | 2012? | |
| China (People's Republic) | None | Postal card back1 (different), also front (different) | 2012? | |
| Cuba | 3718 (Mi3896) | 1996 | (260th anniv. birth) "James Watt" | |
| Germany | None | Cinderella (poster stamp) | early-1900s | "James Watt" |
| Germany | None | Cinderella (poster stamp) (different) | early-1900s | "James Watt" |
| Great Britain | 2646 (Mi2736) | One of pair (2646a (2645-2646)) (Mi2735-2736) | 2009 | "James Watt" |
| Great Britain | 2645-2652 pack | Presentation pack | ||
| Great Britain | P393 | 50 pounds (banknote) | 2011 | "James Watt" (at right) |
| Great Britain | 4139 (Mi4820) | 2021 | "James Watt" rotative steam engine | |
| Great Britain | 4139 card | PHQ card | ||
| Grenada | 1538 (Mi1690) | 1987 | James Watt (mis-identified as "Rudolf Diesel" in text); (250th anniv. birth, in 1986) | |
| Grenada Grenadines | 912 (Mi917) | 1987 | Rudolf Diesel (incorrectly inscribed "James Watt"); (250th anniv. birth, in 1986) | |
| Guinea-Bissau | Mi4221 | One of MS6 (Mi4217-4222) | 2009 | "James Watt" |
| Lesotho | 1213a (Mi1579) | On one stamp and in (lower-left) margin of MS6 (1213 (a-f)) (Mi1579-1584) | 1999 | James Watt (ship, in text) |
| Macedonia | 561 (Mi590) | From MS9 (561a (9x 561)) | 2011 | 275th anniv. birth |
| Macedonia | 561 fdc | Stamp and (pictorial) cancel and (Macedonia Post) cachet on FDC | ||
| Maldive Islands | 2421d (Mi3374) | One stamp and in (left) margin of MS17 (2421 (a-q + label)) (Mi3371-3387) | 2000 | "1769, James Watt, Scottish engineer an inventor, perfects steam engine"; (180th anniv. death, in 1999) |
| Maldive Islands | 2421d maxi | Maxicard | ||
| Mali | 538 (Mi1071) i538 | Imperforate | 1986 | (250th anniv. birth) "James Watt" |
| Mali | 538 ds | Deluxe sheet (538) | ||
| Mali | 581 (Mi1147) | 538 overprinted in black | 1992 | (250th anniv. birth) "James Watt" |
| Marshall Islands | 1032i (Mi2932) | One of MS20 (1032 (a-t)) (Mi2924-2943) | 2012 | "James Watt" |
| Mozambique | Mi10676-10679_ms4 | MS4 (Mi10676-10679) | 2019 | "200th anniv. death James Watt" (in Portuguese text) |
| Mozambique | Mi10676-10679_ms4 fdc | MS4 and (multi-color printed) cachet on FDC | ||
| Mozambique | BL1571 | SS1 (Mi10680) | ||
| Northern Territories Local Post (Japan) | Local_c | One of local post MS6 (a-f) | 2011 | "James Watt" |
| St. Thomas and Prince Islands | 1851e (Mi3498) | One of MS6 (1851 (a-f)) (Mi3494-3499) | 2008 | "James Watt" |
| Sierra Leone | 2296b (Mi3554) | On one stamp and in (right) margin of MS2 (2296 (a-b)) (Mi3553-3554) | 2000 | (180th anniv. death, in 1999) "James Watt" |
| Sierra Leone | 2517e (Mi4155) | One of MS6 (2517 (a-f)) (Mi4151-4156) | 2002 | "James Watt" |
| Togo | Mi10071-10074_ms4 | MS4 (Mi10071-10074) | 2019 | "200th anniv. death James Watt" (in French text) |
| Togo | BL1813 | SS1 (Mi10075) | ||
| Uganda | 566 fdc (Mi556 fdc) | (Fleetwood) cachet on FDC, also back | 1987 | (250th anniv. birth, in 1986) "James Watt" |
| Wallis and Futuna Islands | 341 (Mi511) i341 | Imperforate | 1986 | (250th anniv. birth) "James Watt" |
| Wallis and Futuna Islands | 341 fdc | Stamp and (text) cancel and (Edila) cachet on FDC |
1These postal cards are only some of a large number of similar cards issued by China for various scientists. No effort is made to list all such cards.
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