I was reading a book and this sentence seemed a little odd to me:
At approximately 19.45 hours the two men rose, stretched and yawned. They picked up their gear and stood at the door, …
What does the first part mean? If it's the exact time, shouldn't it be 19:45? And if it's duration, shouldn't it be "After 19.45 hours"?
(The story here happens at an airbase, if it's of any relevance)
Edit: The book I've quoted is this:
The Sirius Crossing by John Creed.
The author is Irish and the text is set in northern England/Ireland.
Best Answer
It means the same as 19:45 or 7:45PM
There seems to be several elements in the original text that are confusing.
The dot
The dot in the time notation is not a decimal point, as in "19 point 45", as in 45 hundredths of an hour. It's an alternative to the colon as the time separator and would be pronounced "nineteen forty five hours".
There are a variety of names for the "dot" symbol, but this one would be a "full stop" or a "period". Both terms are equivalent and are used in Commonwealth English and American English respectively.
Many languages use a dot as a separator between hours, minutes and seconds. In Germany, it was the standard notation up until 1996 and is still commonly seen.
It is also popular in the United Kingdom. For example, The Guardian's recommended style guide has this (emphasis mine):
A quick look at this list of time notations by language reveals that the following are officially using a dot as the separator:
Since the dot serves the same purpose as a colon, the time is meant to be 7 hours after noon (midday), plus 45 minutes.
The "19"
Some cultures do not commonly use the 24-hour clock and a number higher than 12 in a time might be unusual. The 24-hour clock is the most common system in the world today and counts the number of hours passed since midnight, from 0 to 23. It is also called "military time" in the United States.
Therefore, "19" means "19 hours after midnight".
The "hours"
The redundant mention of "hours" after the numbers seems to be common in military settings. This answer on the pronunciation of time in 24-hour notation says that it is ingrained in the mind of soldiers. The Art of Manliness, an American website, also says this:
It would appear that the author wanted to add some military slang since the story happened at an airbase.
At approximately
The phrase "at approximately 19.45" seems unusual for some people who would rather see "about", "roughly" or "around". However, "approximately" reinforces the formality of the sentence, as it is something you might find in reports, legal settings or scientific documents. It sounds much more technical than "around" and again fits with a military setting.
Addendum: Locales
Time and date notations are notoriously difficult to get right. The sum of all the culture-specific quirks (also including number formatting, sorting, case conversions, etc.) is called a locale in computer science. There are as many locales as there are countries and languages. In fact, the "same" language in different countries might have different notations.
For example, in Canada, English and French are the two official languages and have different date notations (dd/mm/yy and yyyy-mm-dd respectively). Canadian English and British English also have different time notations (12-hour clock and 24-hour clock respectively).
In addition to official notations, there are also popular notations that are either:
In this case, the dot is not the official notation in either Ireland or the United Kingdom. It is, however, a popular notation in the UK.