BKRIPPER.RVW   990612

"Ripper", Michael Slade, 1994, 0-451-17702-9, U$6.99
%A   Michael Slade
%C   10 Alcorn Ave, Suite 300, Toronto, Ontario, M4V 3B2
%D   1994
%G   0-451-17702-9
%I   Penguin/Signet
%O   U$6.99 416-925-2249 Fax: 416-925-0068 service@penguin.ca
%P   416 p.
%T   "Ripper"

I did not expect Michael Slade to make it into this series.  Despite
the fact that "he" shares two of my names and my home town, I feel no
real kinship with what is, after all, the pseudonym of two Vancouver
lawyers.  There is also the fact that "Michael Slade" specializes in
horror, which has never been high on my "must read" list.

I must admit that, having read one of "his" books out of random
curiosity, I quite enjoyed it.  While the criminal activities are not
merely gruesome but positively twisted, at least there is some
research and not a little imagination involved.  The characterizations
are full and realistic, even down to the details of petty rivalries. 
The plots are delightfully convoluted, with entire shoals of scarlet
herring, but almost scrupulously fair to the reader.

What gets the book into this series, as with most fictional entries,
is a mistake.  The plot hinges on the belief of a modern satanist
group that the murders of Jack the Ripper were part of an occult
ritual.  Plotting the four "canonical" murders; those which were,
without doubt, committed by the same person; it is determined that
they form a cross shape.  With some quick calculations, detailed in
the text, we find that the odds against this happening are 15,249,024
to one.  Obviously, this can't be random!

Unfortunately, innumeracy is common enough in our society for a lot of
people to believe this explanation.  In fact, the odds are that any
four randomly chosen points *will* form something of a cross shape.

In the book, it is suggested that you can determine the odds by
forming an eight by eight grid over the area you are examining. 
However, the number of divisions in your grid depends upon how precise
you want to make it.  If you are simply looking for a cross shape, any
cross shape, then a two by two grid is more than ample.  Again, the
book advises that the odds of each murder happening in the "right"
place are one divided by the number of squares in the grid, and that
each successive approximation reduces the number of squares by one. 
Thus, the odds are sixty four to one times sixty three to one times
sixty two to one times sixty one to one, giving the number above.

In fact, the first murder can take place anywhere.  Using a reasonably
sized scale, but demanding a fairly definitive cross shape, the second
murder can occur anywhere except in the first square.  (Actually, the
possibilities are slightly better than that, but for simplicity of
calculation we will forego some precision.)  Using the book's own
eight by eight grid would complicate the estimate, so we will reduce
it to the two by two.  The first murder can take place in any of the
four squares.  The second can occur in any of the three remaining, the
third in two of the four, and the last in only one.  Therefore the
odds reduce to four to four times four to three times four to two
times four to one, or odds of about ten to one for a very clear
example.  Well within the bounds of chance, and even more probable
when other directing factors are taken into account.

There is at least one other scientific error.  In a remake of
Christie's "And Then There Were None" (and the use of that plot does
rather give the game away), a vacuum equipped toilet is used as a
death trap.  Let us merely say that, a) most people don't sit on the
john in such a way as to create a vacuum seal, b) toilets have seats,
and thus airgaps, c) you'd need an awfully big vacuum tank, d) "Total
Recall" to the contrary, explosive decompression doesn't work that
fast, and e) by that point, everybody would be spooked enough to use a
chamber pot.

copyright Robert M. Slade, 1999   BKRIPPER.RVW   990612