[tz] Fwd: DST changes in Hungary (full historical revision)
Paul Eggert
eggert at cs.ucla.edu
Fri Jun 12 03:33:51 UTC 2020
On 6/11/20 7:04 AM, Michael H Deckers wrote:
> All of this applies to Monaco and Algiers.
Thanks. I assume the 1911 transition also applies to Tunis, so I installed the
attached patch. This patch also spruces up the comments in the light of your
previous email.
For what it's worth, tzdb still has quite a few transitions that work the way
that 1911 Paris did in tzdb 2020a - that is, clocks move back from midnight to
some time like 23:28:37. That "23:28:37" example is taken from Tunis in 1881;
other examples include Anchorage in 1900 and Buenos Aires in 1920. These
transitions are taken from Shanks, who lists "old time" for transitions and who
is not always reliable.
Unfortunately I doubt whether the transitions in Anchorage etc. will be
documented as well as Paris's stopped clocks....
-------------- next part --------------
diff --git a/NEWS b/NEWS
index 5289d4e..ec73943 100644
--- a/NEWS
+++ b/NEWS
@@ -17,11 +17,12 @@ Unreleased, experimental changes
time was on 11-01, not 10-01 (thanks to Michael Deckers).
The 1911-03-11 French transition from +00:09:21 to +00 is now
- modeled as occurring at 00:09:21, not at 00:01. Legally, clocks
+ modeled as occurring at 00:09:21, not at 00:01. Clocks reportedly
stopped at 00:00 for 9 minutes, 21 seconds but this cannot be
- represented in tzdb, so tzdb instead represents the common
+ represented in tzdb, so tzdb instead represents the also-common
practice of keeping an old clock running until the new clock
- started up. (Thanks to Michael Deckers.)
+ started up. Similarly for the 1891-03-16 transition.
+ (Thanks to Michael Deckers.)
Changes to code
diff --git a/africa b/africa
index 5d3beb0..d5ddbce 100644
--- a/africa
+++ b/africa
@@ -87,11 +87,10 @@ Rule Algeria 1978 only - Mar 24 1:00 1:00 S
Rule Algeria 1978 only - Sep 22 3:00 0 -
Rule Algeria 1980 only - Apr 25 0:00 1:00 S
Rule Algeria 1980 only - Oct 31 2:00 0 -
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
-# more precise 0:09:21.
+# See Europe/Paris for PMT-related transitions.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
-Zone Africa/Algiers 0:12:12 - LMT 1891 Mar 15 0:01
- 0:09:21 - PMT 1911 Mar 11 # Paris Mean Time
+Zone Africa/Algiers 0:12:12 - LMT 1891 Mar 16 0:02:51
+ 0:09:21 - PMT 1911 Mar 11 0:09:21 # Paris MT
0:00 Algeria WE%sT 1940 Feb 25 2:00
1:00 Algeria CE%sT 1946 Oct 7
0:00 - WET 1956 Jan 29
@@ -1464,12 +1463,10 @@ Rule Tunisia 2005 only - Sep 30 1:00s 0 -
Rule Tunisia 2006 2008 - Mar lastSun 2:00s 1:00 S
Rule Tunisia 2006 2008 - Oct lastSun 2:00s 0 -
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
-# more precise 0:09:21.
-# Shanks & Pottenger say the 1911 switch was on Mar 9; go with Howse's Mar 11.
+# See Europe/Paris for PMT-related transitions.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
Zone Africa/Tunis 0:40:44 - LMT 1881 May 12
- 0:09:21 - PMT 1911 Mar 11 # Paris Mean Time
+ 0:09:21 - PMT 1911 Mar 11 0:09:21 # Paris MT
1:00 Tunisia CE%sT
# Uganda
diff --git a/europe b/europe
index 4fa7119..6e3fe33 100644
--- a/europe
+++ b/europe
@@ -606,13 +606,13 @@ Rule C-Eur 1944 only - Oct 2 2:00s 0 -
# corrected in version 2008d). The circumstantial evidence is simply the
# tz database itself, as seen below:
#
-# Zone Europe/Paris 0:09:21 - LMT 1891 Mar 15 0:01
+# Zone Europe/Paris ...
# 0:00 France WE%sT 1945 Sep 16 3:00
#
-# Zone Europe/Monaco 0:29:32 - LMT 1891 Mar 15
+# Zone Europe/Monaco ...
# 0:00 France WE%sT 1945 Sep 16 3:00
#
-# Zone Europe/Belgrade 1:22:00 - LMT 1884
+# Zone Europe/Belgrade ...
# 1:00 1:00 CEST 1945 Sep 16 2:00s
#
# Rule France 1945 only - Sep 16 3:00 0 -
@@ -1326,6 +1326,10 @@ Link Europe/Helsinki Europe/Mariehamn
# Françoise Gauquelin, Problèmes de l'heure résolus en astrologie,
# Guy Trédaniel, Paris 1987
+# From Michael Deckers (2020-06-11):
+# the law of 1891 <https://gallica.bnf.fr/ark:/12148/bpt6k64415343.texteImage>
+# was published on 1891-03-15, so it could only take force on 1891-03-16.
+
# From Michael Deckers (2020-06-10):
# Le Gaulois, 1911-03-11, page 1/6, online at
# https://www.retronews.fr/societe/echo-de-presse/2018/01/29/1911-change-lheure-de-paris
@@ -1338,7 +1342,7 @@ Link Europe/Helsinki Europe/Mariehamn
# he announced "Heure nouvelle". See the "Le Petit Journal 1911-03-11".
# https://gallica.bnf.fr/ark:/12148/bpt6k6192911/f1.item.zoom
#
-# From Paul Eggert (2020-06-10):
+# From Paul Eggert (2020-06-11):
# French time in railway stations was legally five minutes behind civil time,
# which explains why "old time" ran to 00:04:21 instead of to 00:09:21.
# The Brooklyn Daily Eagle Almanac (1912), page 494, says:
@@ -1351,9 +1355,18 @@ Link Europe/Helsinki Europe/Mariehamn
# to whether or not a child that was born and died within the elapsed
# time could be said to have legally lived.
#
+# There are similar stories in the Washington Herald and Washington Times
+# (1911-03-11). The law's text (which Michael Deckers noted is at
+# <https://gallica.bnf.fr/ark:/12148/bpt6k2022333z/f2>) says only that
+# at 1911-03-11 00:00 legal time was that of Paris mean time delayed by
+# nine minutes and twenty-one seconds, and does not say how the
+# transition from Paris mean time was to occur.
+#
# tzdb has no way to represent stopped clocks. As the railway practice
# was to keep a watch running on "old time" to decide when to restart
# the other clocks, model this as a transition for "old time" at 00:09:21.
+# Do something similar for the 1891-03-16 transition, which has a similar
+# problem in Algiers and Monaco.
#
# Shank & Pottenger seem to use '24:00' ambiguously; resolve it with Whitman.
@@ -1417,12 +1430,10 @@ Rule France 1945 only - Sep 16 3:00 0 -
# go with Excoffier's 28/3/76 0hUT and 25/9/76 23hUT.
Rule France 1976 only - Mar 28 1:00 1:00 S
Rule France 1976 only - Sep 26 1:00 0 -
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time, and Whitman 0:09:05,
-# but Howse quotes the actual French legislation as saying 0:09:21.
-# Go with Howse. Howse writes that the time in France was officially based
+# Howse writes that the time in France was officially based
# on PMT-0:09:21 until 1978-08-09, when the time base finally switched to UTC.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
-Zone Europe/Paris 0:09:21 - LMT 1891 Mar 15 0:01
+Zone Europe/Paris 0:09:21 - LMT 1891 Mar 16
0:09:21 - PMT 1911 Mar 11 0:09:21 # Paris MT
# Shanks & Pottenger give 1940 Jun 14 0:00; go with Excoffier and Le Corre.
0:00 France WE%sT 1940 Jun 14 23:00
@@ -2064,11 +2075,10 @@ Zone Europe/Chisinau 1:55:20 - LMT 1880
2:00 Moldova EE%sT
# Monaco
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
-# more precise 0:09:21.
+# See Europe/Paris for PMT-related transitions.
# Zone NAME STDOFF RULES FORMAT [UNTIL]
-Zone Europe/Monaco 0:29:32 - LMT 1891 Mar 15
- 0:09:21 - PMT 1911 Mar 11 # Paris Mean Time
+Zone Europe/Monaco 0:29:32 - LMT 1891 Mar 16 0:20:11
+ 0:09:21 - PMT 1911 Mar 11 0:09:21 # Paris MT
0:00 France WE%sT 1945 Sep 16 3:00
1:00 France CE%sT 1977
1:00 EU CE%sT
More information about the tz
mailing list