[tz] Some time zone history (1)
Paul Eggert
eggert at cs.ucla.edu
Wed Nov 25 06:13:55 UTC 2020
On 11/20/20 7:00 AM, P Chan wrote:
> Apart from the current rules, DST was also observed in 1917-1918, 1942-1945, 1947-1952 and 1956.
Thanks again. I installed the attached proposed patch to incorporate your
citations for Bermuda. I added a citation for the 1930-01-01 transition from
Bermuda Mean Time to -04. For this patch I also invented the abbreviations BMT
and BST for Bermuda Mean Time and Bermuda Summer Time, since we can't use
numeric offsets as abbreviations here for the usual reasons.
Ghana should be next.
-------------- next part --------------
From 17acee8cbb75aaf7bca5decc4fc6c9ab27533537 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert at cs.ucla.edu>
Date: Tue, 24 Nov 2020 22:05:38 -0800
Subject: [PROPOSED] Fix several pre-1957 transitions for Bermuda
(Thanks to P Chan.)
* NEWS: Mention this.
* northamerica (Bermuda): New ruleset.
(Atlantic/Bermuda): Use it before 1974.
* theory.html (Time zone abbreviations): Mention BMT/BST,
which are my invention.
---
NEWS | 5 +--
northamerica | 95 +++++++++++++++++++++++++++++++++++++++++++++++++---
theory.html | 5 +--
3 files changed, 97 insertions(+), 8 deletions(-)
diff --git a/NEWS b/NEWS
index f7b0461..d9fe116 100644
--- a/NEWS
+++ b/NEWS
@@ -4,9 +4,10 @@ Unreleased, experimental changes
Changes to past timestamps
- Correct several pre-1972 transitions, fixing entries originally
+ Correct many pre-1986 transitions, fixing entries originally
derived from Shanks. The fixes include:
- - Australia: several 1917 through 1971 transitions.
+ - Australia: several 1917 through 1971 transitions
+ - Bermuda: several 1917 through 1956 transitions
- Belize: several 1942 through 1968 transitions
- Israel and Palestine: several 1940 through 1985 transitions
- Kenya and adjacent: several 1908 through 1960 transitions
diff --git a/northamerica b/northamerica
index 6a66617..d5abf21 100644
--- a/northamerica
+++ b/northamerica
@@ -3018,20 +3018,107 @@ Zone America/Belize -5:52:48 - LMT 1912 Apr 1
# Bermuda
+# From Paul Eggert (2020-11-24):
# For 1899 Milne gives -4:19:18.3 as the meridian of the clock tower,
-# Bermuda dockyard, Ireland I; round that.
+# Bermuda dockyard, Ireland I. This agrees with standard offset given in the
+# Daylight Saving Act, 1917 cited below. Round that to the nearest second.
+# It is not known when this time became standard for Bermuda; guess 1890.
+# The transition to -04 was specified by:
+# 1930: The Time Zone Act, 1929 (1929: No. 39) [1929-11-08]
+# https://books.google.com/books?id=7tdMAQAAIAAJ&pg=RA54-PP1
+
+# From P Chan (2020-11-20):
+# Most of the information can be found online from the Bermuda National
+# Library - Digital Collection which includes The Royal Gazette (RG) until 1957
+# https://bnl.contentdm.oclc.org/digital/
+# I will cite the ID. For example, [10000] means
+# https://bnl.contentdm.oclc.org/digital/collection/BermudaNP02/id/10000
+#
+# 1917: Apr 5 midnight to Sep 30 midnight
+# Daylight Saving Act, 1917 (1917 No. 13) [1917-04-02]
+# Bermuda Acts and Resolves 1917, p 37-38
+# https://books.google.com/books?id=M-lCAQAAMAAJ&pg=PA36-IA2
+# RG, 1917-04-04, p 6 [42340] gives the spring forward date.
+#
+# 1918: Apr 13 midnight to Sep 15 midnight
+# Daylight Saving Act, 1918 (1918 No. 9) [1918-04-06]
+# Bermuda Acts and Resolves 1917, p 13
+# https://books.google.com/books?id=K-lCAQAAMAAJ&pg=RA1-PA7
+#
+# Note that local mean time was still used before 1930.
+#
+# During WWII, DST was introduced by Defence Regulations
+# 1942: Jan 11 02:00 to Oct 18 02:00 [113646], [115726]
+# 1943: Mar 21 02:00 to Oct 31 02:00 [116704], [118193]
+# 1944: Mar 12 02:00 to Nov 5 02:00 [119225], [121593]
+# 1945: Mar 11 02:00 to Nov 4 02:00 [122369], [124461]
+# RG, 1942-01-08, p 2, 1942-10-12, p 2 , 1943-03-06, p 2, 1943-09-03, p 1,
+# 1944-02-29, p 6, 1944-09-20, p 2, 1945-02-13, p 2, 1945-11-03, p 1
+#
+# In 1946, the House of Assembly rejected DST twice. [128686], [128076]
+# RG, 1946-03-16 p 1,1946-04-13 p 1
+#
+# 1947: third Sunday in May 02:00 to second Sunday in September 02:00
+# DST in 1947 was defined in the Daylight Saving Act, 1947 (1947: No. 12)
+# which expired at the end of the year. [125784] ,[132405], [144454], [138226]
+# RG, 1947-02-27, p 1, 1947-05-15, p 1, 1947-09-13, p 1, 1947-12-30, p 1
+#
+# 1948-1952: fourth Sunday in May 02:00 to first Sunday in September 02:00
+# DST in 1948 was defined in the Daylight Saving Act, 1948 (1948 : No. 12)
+# which was set to expired at the end of the year but it was extended until
+# the end of 1952 and was not further extended.
+# [129802], [139403], [146008], [135240], [144330], [139049], [143309],
+# [148271], [149773], [153589], [153802], [155924]
+# RG, 1948-04-13, p 1, 1948-05-22, p 1, 1948-09-04, p 1, 1949-05-21, p1,
+# 1949-09-03, p 1, 1950-05-27 p 1, 1950-09-02, p 1, 1951-05-27, p 1,
+# 1951-09-01, p 1, 1952-05-23, p 1, 1952-09-26, p 1, 1952-12-21, p 8
+#
+# In 1953-1955, the House of Assembly rejected DST each year. [158996],
+# [162620], [166720] RG, 1953-05-02, p 1, 1954-04-01 p 1, 1955-03-12, p 1
+#
+# 1956: fourth Sunday in May 02:00 to last Sunday in October 02:00
+# Time Zone (Seasonal Variation) Act, 1956 (1956: No.44) [1956-05-25]
+# Bermuda Public Acts 1956, p 331-332
+# https://books.google.com/books?id=Xs1AlmD_cEwC&pg=PA63
+#
+# The extension of the Act was rejected by the House of Assembly. [176218]
+# RG, 1956-12-13, p 1
+#
+# From the Chronological Table of Public and Private Acts up to 1985, it seems
+# that there does not exist other Acts related to DST before 1973.
+# https://books.google.com/books?id=r9hMAQAAIAAJ&pg=RA23-PA1
+# Public Acts of the Legislature of the Islands of Bermuda, Together with
+# Statutory Instruments in Force Thereunder, Vol VII
# From Dan Jones, reporting in The Royal Gazette (2006-06-26):
-
# Next year, however, clocks in the US will go forward on the second Sunday
# in March, until the first Sunday in November. And, after the Time Zone
# (Seasonal Variation) Bill 2006 was passed in the House of Assembly on
# Friday, the same thing will happen in Bermuda.
# http://www.theroyalgazette.com/apps/pbcs.dll/article?AID=/20060529/NEWS/105290135
+# Rule NAME FROM TO - IN ON AT SAVE LETTER/S
+Rule Bermuda 1917 only - Apr 5 24:00 1:00 -
+Rule Bermuda 1917 only - Sep 30 24:00 0 -
+Rule Bermuda 1918 only - Apr 13 24:00 1:00 -
+Rule Bermuda 1918 only - Sep 15 24:00 0 S
+Rule Bermuda 1942 only - Jan 11 2:00 1:00 D
+Rule Bermuda 1942 only - Oct 18 2:00 0 S
+Rule Bermuda 1943 only - Mar 21 2:00 1:00 D
+Rule Bermuda 1943 only - Oct 31 2:00 0 S
+Rule Bermuda 1944 1945 - Mar Sun>=8 2:00 1:00 D
+Rule Bermuda 1944 1945 - Nov Sun>=1 2:00 0 S
+Rule Bermuda 1947 only - May Sun>=15 2:00 1:00 D
+Rule Bermuda 1947 only - Sep Sun>=8 2:00 0 S
+Rule Bermuda 1948 1952 - May Sun>=22 2:00 1:00 D
+Rule Bermuda 1948 1952 - Sep Sun>=1 2:00 0 S
+Rule Bermuda 1956 only - May Sun>=22 2:00 1:00 D
+Rule Bermuda 1956 only - Oct lastSun 2:00 0 S
+
# Zone NAME STDOFF RULES FORMAT [UNTIL]
-Zone Atlantic/Bermuda -4:19:18 - LMT 1930 Jan 1 2:00 # Hamilton
- -4:00 - AST 1974 Apr 28 2:00
+Zone Atlantic/Bermuda -4:19:18 - LMT 1890 # Hamilton
+ -4:19:18 Bermuda BMT/BST 1930 Jan 1 2:00
+ -4:00 Bermuda A%sT 1974 Apr 28 2:00
-4:00 Canada A%sT 1976
-4:00 US A%sT
diff --git a/theory.html b/theory.html
index 4613799..28f6b8e 100644
--- a/theory.html
+++ b/theory.html
@@ -474,8 +474,8 @@ in decreasing order of importance:
<p>
<small>These abbreviations are:
AMT Amsterdam, Asunción, Athens;
- BMT Baghdad, Bangkok, Batavia, Bern, Bogotá, Bridgetown, Brussels,
- Bucharest;
+ BMT Baghdad, Bangkok, Batavia, Bermuda, Bern, Bogotá, Bridgetown,
+ Brussels, Bucharest;
CMT Calamarca, Caracas, Chisinau, Colón, Copenhagen, Córdoba;
DMT Dublin/Dunsink;
EMT Easter;
@@ -506,6 +506,7 @@ in decreasing order of importance:
<small>A few abbreviations also follow the pattern that
<abbr>GMT</abbr>/<abbr>BST</abbr> established for time in the UK.
They are:
+ BMT/BST for Bermuda 1890–1930,
CMT/BST for Calamarca Mean Time and Bolivian Summer Time
1890–1932,
DMT/IST for Dublin/Dunsink Mean Time and Irish Summer Time
--
2.27.0
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