[MacLoggerContest] The number of dit durations in a word

[Chuck Counselman]

At 4:15 AM -0500 3/13/05, Don Agro wrote:
>...assuming an average of 48 dit durations in a word....

This off-topic and trivial, but perhaps others are interested as I am.

I don't know where I learned it, much less whether it's correct, but 
for about 35 years I've thought that the canonical "word" for 
measuring the speed of sending Morse code in words per minute was 
"PARIS_" where I've typed an underline character to represent the 
space between words.  Assuming that the duration of a dah is equal to 
three dit-durations; one dit-duration between each dit or dah within 
a letter; one dah-duration between letters; and three dah durations 
between words, I calculate that the duration of "PARIS_" is 52 
dit-durations.

So, I wonder, whence comes the value 48?

73 de Chuck, W1HIS