In Pursuit of JtR, by Robert A. Snow

[Colin Roberts]

Other than your beef about profiling, which really takes up only a few pages in the book, what was your overall impression of it?

Hey Ken,

No 'beef', to be honest! I think that his focus on George Yard is actually quite reasonable.

And, as I stated earlier, I intend to expound on the tremendous degree of 'influence' that is exerted by the placement of the Tabram murder-site, on the central tendency of all of the applicable murder-sites.

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I rather like the layout.

No exponentially recycled introduction, in which London's 'East End', of 1888, is described as having been a vast and continuous hovel, of the worst imaginable magnitude.

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The Murders
Chapter 1: Smith
Chapter 2: Tabram
Chapter 3: Nichols

...

Chapter 10: Coles

The Pursuit
Chapter 11: a comparative analysis of the victims
Chapter 12: a comparative analysis of the crime scenes
Chapter 13: a comparative analysis of the victims' wounds

...

Chapter xx: etc.

All in all, what I would imagine is a typical 'investigative' format.

[The Grave Maurice]

Interesting observations, as usual, Colin---and I always enjoy your maps. You're quite right about George Yard Buildings: I meant to type simply George Yard, but my fingers seem, occasionally, to operate independent of my brain.

I lumped in the mistake about Cross's middle name with the other minor errors since I don't think a newcomer, reading an introductory account, would care what his middle name was. And I can't raise much enthusiasm about his using the name Cross instead of Lechmere. Snow may think, like me, that whatever Cross's reason was for using that name, he seemed to act like a model citizen. In any event, the Cross/Lechmere thing is the sort of minutiae that can wait until a newbie is much deeper into this subject.

Other than your beef about profiling, which really takes up only a few pages in the book, what was your overall impression of it?

[Colin Roberts]

There are a few errors, but not many: Joseph "Love" was living temporarily at the IWEC (typo, I assume); Polly Nichols was murdered on August 13 (simple transposition, I assume).

Charles "Andrew" Cross

Charles Allen Lechmere identified himself, during the course of the investigation, into the death of Mary Ann Nichols, as Charles "Allen" Cross.

I also believe that failure to mention the fact that his name was actually 'Lechmere', is a mistake, in itself.

There is a good, clear statement of the difference between M.O. and signature, and a concise overview of geographic profiling. (Snow reckons that JtR lived in George Yard Buildings).

"A technique which may have led the police to George Yard is Geographic Profiling. ..."

"A review of the locations of the ten Whitechapel murders addressed in this book shows an elongated circle with George Yard near its center. If the Tabram murder was in fact the first of the Ripper series, it would seem that George Yard would indeed be a candidate for special attention."

The "ten Whitechapel murders addressed in this book" are exclusive of the Pinchin Street Torso, as the author quickly dismisses its discovery, as being more-or-less irrelevant to the study of 'Jack the Ripper'.

"Snow reckons that JtR lived in George Yard Buildings"

I don't believe that he 'extends his neck', quite that far, Ken; as he would effectively be laying his head on the chopping block, were he to do so.

I wish that I could impress upon the field of 'Ripperology', the fact that no geographic profile would ever attempt to pinpoint a particular location, as being the 'probable' base of the offender that is being sought.

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If I were in possession of two tickets, from a total lottery of one hundred, from which a single raffle was to be drawn; and each of the remaining ninety eight tickets was individually held; then I would be the single most likely winner. However, I would not be a 'probable' winner, as the actual probability that one of my two tickets would be drawn, would be just two percent.

Mr. Snow is suggesting that a particular point, within the immediate vicinity of the thoroughfare, George Yard, should be perceived as having been the single most likely location of the operational base and/or residence, of 'Jack the Ripper'. But, he is not suggesting that this particular point - or, for that matter, any other point - should be perceived as having been the 'probable' location of this most elusive 'landmark'.

In fact, no meaningful geographic profile would afford any more than two-to-three percentage points, of its probability distribution, to the immediate vicinity of the thoroughfare, George Yard: - or, for that matter, any other thoroughfare of similar length - Thus, rendering its 'prospects' as being similar to mine, in the aforementioned lottery ticket scenario.

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I believe the concept of a so-called 'probability distribution' is confusing many of those that have had difficulty, following my lines of reason.

After all, what, exactly, is a 'probability distribution'?

I am considering the presentation of one-or-two analogous concepts¹ that may 'shed some light', so to speak. I shall address these concepts, albeit in a new thread, both here, and in JTRForums.com, over the course of the next four-to-five days.

I shall also return to this thread, in order to briefly address the remarkable degree of 'magnetism' that the Tabram murder-site exerts, on the central tendencies of various combinations of those murder-sites, which we take into account, when studying the mystery of 'Jack the Ripper'.

Case in Point:

The Center of Minimum Distance - i.e. the point, from which the aggregate distance, to each member of a set of observations, is minimized - of the set of ten murder-sites that are taken into account, by Mr. Snow, is the Tabram murder-site.

In other words; the Tabram murder-site is the point, on the whole of the earth's surface, from which the total distance, to the Smith, Tabram, Nichols, Chapman, Stride, Eddowes, Kelly, Mylett, McKenzie, and Coles murder-sites, is minimized.

The point!

The Center of Minimum Distance, by definition, bears one of the two main attributes, that would be seen in a 'Two-Dimensional Median', were one to actually exist.

The Tabram murder-site, therefore, can reasonably be thought of as being, the median of the ten murder-sites that are under consideration, in this particular instance.

Incidentally, the Tabram murder-site is also the Center of Minimum Distance, of the six murder-sites that are normally included in my geographic spatial analysis endeavors: Tabram, Nichols, Chapman, Stride, Eddowes, and Kelly.

It might interest Rob House, et al, to know that the Mean-Center, - i.e. the 'Two-Dimensional Mean', which unlike the 'Two-Dimensional Median', does actually exist - of the ten murder-sites that are taken into account, by Mr. Snow, is a point on the west side, of the southern half of Greenfield Street.

--- More to Follow ---

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¹ One being a circular distribution of precipitation, i.e. 'rainfall', that is being detected, by way of a type of Doppler radar, and in turn, depicted, by way of a set of colorful isopleths, which show diminishing levels of precipitation density, from the center, to the periphery, of the area, on which the rainfall is landing.

A simple concept, which I am sure, we all understand.

My challenge will be to successfully correlate this concept, with that of a geographic profile probability distribution, and its inherent implications.


Cumulative Probability Distributions (Murder-Site Population & Geographic Profile Model) (Circular) (Click Image, to Enlarge in flickr)
Underlying Aerial Imagery: Copyright Google Earth, 2007
Overlying Plots, Labels and Color-Shadings: Copyright Colin C. Roberts, 2010

--- More to Follow ---

... on a new thread.

[The Grave Maurice]

Robert A. Snow, In Pursuit of Jack the Ripper: An Introduction to the Whitechapel Murders. Denver: Outskirts Press, 2011. ISBN 978-1-4327-6434-0

One of the difficulties I have with introducing friends or family members to the study of JtR is the length of the best books. When someone asks me about a good source on the subject, I show them Sugden or Begg and their jaws usually drop. "That looks like a bit more than I wanted to know" is their usual reaction.

It's hard to find a recent, short, accurate account of the WMs, but we might have one here. This one is set in a largish font, with lots of white space, and could be read by most people in a couple of sittings during a wet weekend. Another good thing is that it has no postmortem pictures (which often scare off the newbies) but it does have a helpful diagram of the wounds inflicted upon 8 victims.

Snow is a former Deputy Chief with the Suffolk County (New York) Police Department who served in a variety of posts, and he approaches the WMs as a cold case. His is a Joe Friday kind of book ("Just the facts, ma'am). No speculation, no theories, just the data culled from the inquests, newspapers, and some of the standard texts.

He concludes that the C5 fell victim to JtR, as well as Tabram, McKenzie, and Coles. He's quite adamant about including Tabram, as well as the fact that MJK's heart was actually found somewhere at the murder site. (This point is currently being discussed on the MJK "Heartless?" thread.)

There are a few errors, but not many: Joseph "Love" was living temporarily at the IWEC (typo, I assume); Polly Nichols was murdered on August 13 (simple transposition, I assume). And he must have consulted an older edition of the A-Z because he spells Eddowes' first name as Catharine. The rest of the errors are minor and should have been caught by a competent editor.

There is a fair amount of repetition of the facts, but I suspect that would be helpful to newbies. There is a good, clear statement of the difference between M.O. and signature, and a concise overview of geographic profiling. (Snow reckons that JtR lived in George Yard Buildings).

In short, what we have here is a brief, well-written tome with easily correctable errors. Just the sort of thing I've been looking for.