3 Minute Marks on Pilot’s Chronographs: (Partially) Debunking Myths and (Some) Dead Reckoning

A Smiths timer that you posted above mentions a 12 second rate. Maybe this has something to do with the presumably 48 second sub-dial?

Ah yes, that must be it: I read elsewhere those Smith’s devices were made for/utilized at the UK post offices for timing calls, which for “local” calls utilized different rate structures such as these

So too for these, I suppose

Going today through this thread by @Dre , in which he shares various period UG catalogues - that I believe are each directed toward the American market.

As he posted expressly with the intend of folks’ making use in their research, I don’t think he’ll mind me posting one such catalogue in full in order to note a few key characteristics:

-> This catalogue is from 1949, for the American market, and intended to be a thorough brochure for sales people to educate themselves on the various UG products, their uses, etc. (see the intro letter in first photo).

-> There is some prominent discussion around a chrono being important to air and sea navigation, in calculating not only speed but bearings and plotting - I’ve boxed in red.

-> There are many models displayed with the 3/6/9 emphasis, but none with full 3-min denominated totalizers. In fact, other than the calendar (or photo) watches without a minute totalizer, it appears every other watch in the catalogue contains the 3/6/9 emphasis marks.

-> The catalogue never once mentions nor explains the 3/6/9 marks, despite going through some great lengths to discuss any number of other functions of the watches.

-> The “Pilot’s watch” has the 3/6/9 emphasis but otherwise appears to have a normal 30 minute totalizer.




The few other brochures at the linked thread follow this same pattern.

In all, then:

-> the U.G. marketing materials directed to the U.S. make. I mention of timing phone calls, despite every applicable watch having the 3/6/9 markings and the brochures otherwise going to some length to explain the myriad of functions performed

-> at the same time, the materials also do not explicitly mention the 3/6/9 units as being relevant to navigation

-> however, this brochures in particular, more thorough than the others in being an education pamphlet for sales persons, does give as much or more text to discussing air/sea navigation than to other subjects of function we may have expected; and these discussions while brief are not limited to merely calculating speed, or limited to discussing the tachy.

I’d be very interested to see a Euro-targeted version of such a sales person brochure.

Thanks to Andre for having shared these materials; I’d encourage those interested to go “flip through” a few of the other brochures.

From the same thread noted immediately above, but this time a period pamphlet from a Lucerne jeweler/dealer: while not as thorough in attempting to explain all functions of the models highlighted, worth noting that 2 of 3 watches highlighted have the 3/6/9 emphasis, but no discussion of their utility.

So, in contrast to the American-targeted pamphlet above (or others in the other thread), here is one targeted instead toward Switzerland but just the same also not mentioning the 3/6/9 marks even when highlighting the various utilities of the watch.

I remember having a party line as a young kid in SoCal. You'd pick up the phone to call your friend and hear a juicy conversation between two lovers on the other side. Great fun till the giggling gave you away.

Collecting some other (modest) data-points from period literature, here still focused to far on UG, but this time from what I assume to be the early/mid-1960s (given models shown) and targeted toward German audiences. The entire brochure and translation may be found over at Alpha Hands but in most relevant portion:



“The most common applications of Compax chronographs

Universal-Geneve produces various luxury chronographs based on the “Compax”, which, depending on their specific functions, realize the full range of checks and calculations: speed, distances, athletic events, rallies, parking times, duration of filming, radio broadcasts, industrial times, human or machine performance, departure or landing maneuvers, etc….

The COMPAX

The COMPAX is a basic chronograph equipped with a tachometer, i.e. a scale that allows you to measure the speed of a vehicle.

Due to the draw of the chronograph and the stopping of this second hand a kilometer - or one mile - further, the speed per hour, measured in basic units, can be read on the ring.

For example, the COMPAX allows you to check the accuracy of the speedometer of your vehicle.

In practice, the COMPAX provides the greatest and most useful value from speeds between 60 and 500 km/h.”


Notably, 3 out of 4 chronographs featured contain the 3/6/9 emphasis marks, and despite the laundry list of chrono features mentioned - even when facing a German market:

(1) make no mention of timing telephone calls, but

(2) do mention (perhaps obviously given the tachy) “speed” but then (perhaps less obviously) also “distances … departure or landing maneuvers”

Meanwhile, given the my watch used to start this thread, if there are any generous German speakers who might like to translate this portion of the brochure I’d be much appreciative - especially as may relate to any explanation of the 15 rather than 30 minute totalizer (which I can see is discussed):

Last bit translated using Google: "The AERO-COMPAX provides excellent services to all major travelers, airlines, international transport and travel companies and, last but not least, to all business people who are in constant telephone contact with other countries."

Neither does the catalogue explain why the main dial is divided into 12 + 60 markings, nor why there are two hands rotating at different speeds. Everyone buying a watch already knows all about that, right? So, perhaps the 3/6/9 marks were already something that everyone knew about. In the 1960s I certainly knew about the charge in 3 minute intervals for non-local calls and that there was no notification on domestic lines, unlike phone-boxes where there was a demand for more money to be inserted.

Continuing the collection of primary materials, this one being the most [interesting/ironic] to date wrt the topic of this thread:

Below is a Breitling catalogue that is:

(A) from 1946
(B) marketed to multiple languages/countries

The entire catalogue can be found here, though unfortunately the photos provide very poor legibility - if anyone knows where to find the full catalogue in clearer texts, please let me know.

Meanwhile, it’s that - while legibility is poor - I can find no discussion of telephone call timing, but instead a discussion of using the chronograph for the “rule of three”…




Amy best attempt at a “translation” of the poor legibility:

“
“The only chronograph with slide rule for calculating which permits in addition to the TACHYMETER - PULSOMETER - TELEMETER - PRODUCTION - METEROLOGY - CALCULATIONS also the MULTIPLICATIONS and DIVISIONS. Mathematical problems such as the RULE OF THREE, COST PRICES, EXCHANGE and [INT]ERESTS are easily executable with the CHRONOMAT[.] in one word, a chronograph for SPORT and WORK….”

Now, the chronomat was not strictly a pilot’s watch so much as a slide rule watch geared toward, say, workers such as engineers, mechanics, and the like, but also “sport.” And, the literature’s framing places this “rule of three” in a category of mathematical problems seemingly dealing as a category with money/accounting related questions. And of course, the literature does not attribute this “rule of three” or any other functions with the dial’s 3/6/9 emphasis (found on most/all? chronomats). The language appears to be focused toward the functions of the slide rule in performing “in addition to” the tachy’s function other mathematical calculations - but not entirely discounting the possibility of pumping together other dial features, such as the 3/6/9 emphasis.

If anything, this framing of “the rule of three” in connection with (possibly) the slide rule adds a new flare to the 3/6/9 mystery, but meanwhile worth noting that this period, multi-lingual, brochure makes no apparent mention of telephone call timing (though a more legible copy would be welcome), but does in talking about chronograph’s helpful functions reference a “rule of three” which references a watch with the 3/6/9 emphasis but also the slide rule functionality.

yes, though in this context it is almost certainly talking about the 24hr capabilities - note that this Aero-Compax model is (ironically in the context of this thread) the only watch in the brochure that doesn’t have the 3/6/9 emphasis.

So here in reference to the Aero-Compax’s dual 24hr dial and no 3/6/9 emphasis, the reference to people telephoning other countries seems to surely be referencing the dual time zone capabilities.

Well if you’re singling out this one brochure, this seems a more reasonable observation: but if you look across the brochures reviewed so far, but especially including the “salesman” brochure earlier discussed, they do in fact seem to discuss in some details almost every nuance of the chronograph’s functionality.


Remembering that in the contexts of some of these earlier brochures, even to salespersons, chronographs and their functionalities were not so widely understood - and so it would be I think not quite right to say that because they didn’t explain how a normal clock/time-telling works (your suggestion) that they, too, also wouldn’t need to explain the 3/6/9 within the chronograph function despite otherwise going to great lengths to otherwise sell almost any feasible utility of the less commonly understood chronograph (eg, exposing photographs, timing radio broadcasts, etc.). With the totalizers, these go so far as to explain in detail that a specific totalizer goes around the dial once every 15 minutes, etc.

In that context, the possibility you mention is noted but seems dubious.

Otherwise, in case it wasn’t clear enough, I’m collecting (and continuing to collect) these instances both “for” or “against” a singular answer to “the question” precisely because (A) none clearly give a faultless explanations, and (B) I’m increasingly if the mind that there are multiple, overlapping, explanations.

But I would think one need to at this point at least begin to grant that: if these 3/6/9 emphasis dials were so widely and singularly intended to time long distance telephone calls in Europe (but not, e.g., the US or several other countries that did not follow Europe’s charge convention), then:

(A) it’s interesting and consistent that the U.S. salesman’s brochure doesn’t mention telephone timing at all (despite seeming to attempt to “sell” every other conceivable functionality, and going to great lengths to in particular explain every detail of the chronograph functionality); and

(B) interesting and odd for European-focused brochures full of 3/6/9 emphasized dials, also otherwise going to some length to “sell” any number of possible utilities of the chronograph, there has not yet been a mention of telephone timing.

Again, not at all of course suggesting anything definitive by way of just a handful of brochures.

But in contrast, earlier in the thread, a single unsupported assertion in one watchmaker’s pamphlet that the 3/6/9 emphasis were for timing calls was quickly taken up as deep proof of a singular explanation.

I instead assume we’re interested in seeing a broad spectrum of period, but especially manufacturer-driven, marketing regarding the purported utility of these chronographs.

And while we’ve barely scratched the surface (I’ve reviewed many more than what I’ve posted here), I’ve not yet found a single mentioned from period marketing correlating the 3/6/9 emphasis to telephone calls.

Though, I do suspect to find them, since I’ve agreed that this appears to have been an extremely plausible explanation of the “mere” 3/6/9 emphasis dials as relates to Europe (making the marks basically vestigial in the US and many other countries).

All good comments and pressure toward more info! Thank you!

Here adding that, in connection with this reference to the “rule of three” I’m suspecting it is getting instead at this (and so a utility of the slide rule bezel) - perhaps some slide rule experts can weigh in:

“
Rule of Three
The so-called rule of three is an educational tool utilized historically to verbalize the process of solving basic linear equations with four terms where three of the terms are known. Evidence suggests that there are two "different" rules of three: One direct and one inverse.

The direct rule of three describes the process for finding the fourth term of a proportion


(1)
given that , , and are known. In words, the solution is to "multiply the second and third numbers together, and divide product by the first" so that the term in equation (1) above becomes


(2)
The inverse rule of three describes the process of solving for when and , , and are known. In words, one solves the problem by "multiplying the first and second terms together, and dividing the product by the third" so that

”

Not all.

https://www.fratellowatches.com/tbt-breitling-chronomat-808-chronograph/#gref

Another Breitling catalogue, this time in French and from 1964. The remainder of the catalogue can be found here.

I scanned the French remainder of the catalogue for reference to telephone, seeing none.

But I was particularly keen to see the description for that year’s model AVI, which has the “big eye” totalizer that is relevant to this thread in two ways: first, it’s “big eye” is a 15 minute totalizer, and second, it’s divided into three minute lumed sections throughout. This then is not the “mere” 3/6/9 emphasis on a dial, but instead the sort-of “full” treatment.



The AVI’s description google-translated as (welcome any native tongue corrections of course):

“The AVI is the co-pilot chronograph, equipped with a 15-minute totalizer with a large luminous hand for take-off and landing operations, and a flight totalizer up to 12 hours. It is also recommended for yachting.

Interesting that this focus here is on “take-off and landing operations” as I’ve seen it said elsewhere that, for Breitling, the historical story of the 15 minute totalizer had something to do with pre-flight check times of some sort - though I’ve never seen information backing up the substance of those assertions. Until then, this definitely needs follow-up, but has a slight vibe of rumors-become-marketing-campaign.

yes thank you; while not altogether clear, it certainly on further inspection seems that the chronomat’s reference to the “rule of three” has to do instead with the slide rule, and the mathematical proportions rule the slide rule purports to be able to address.

Just what we needed, a new/different rule of 3.

Thank you for all the great additions and clarifications to the thread

Going through On The Dash’s collection of Heuer catalogues, which are presented chronologically, I noted:

ON THE WAY IN:

Prior to a 1945 catalogue, there were no models of wristwatch chronographs with any of (1) the “mere” 3/6/9 emphasis on otherwise normal totalizer, or (2) a 15 totalizer, or (3) a totalizer displayed in 3 minute increments.

In a large 1942 catalogue (in French and German), many (half?) of stopwatches contained 30 minute totalizers in increments of 3 minute marks, or 15 minute totalizers in 3 minute increments.

OTD’s catalogue collection then jumps three years to 1945, and a 3/6/9 emphasis is on the cover:




And in this 1945 catalogue (also in both French and German), over half of the chronographs have the 3/6/9 emphasis; this is a typical page:


And the page describing the functionality of the tachymeter uses as it’s example a watch with the 3/6/9 emphasis, but appears (through my very bad French) to contain no mention or explanation:



By the 1946 chronograph catalogue, 8 out 9 models featured contained the 3/6/9 emphasis, and no mention of why. (No watches had 15 minute totalizers or 3 minute increments.)

So at least from Heuer, in 1942 they offered no chronograph with the 3/6/9 emphasis, by 1945 over half the models did, and by 1946 essentially every model did.

FIRST “PILOT’S” WATCH (SORT OF):

OTD’s catalogue collection next jumps years a bit through to the early 1960’s, but every wrist chronograph shown has the 3/6/9 demarcation, until a 1962 chrono catalogue that (among all the other chronographs with 3/6/9 demarcation) introduces the Autiva watch:




With the Autiva, Heuer was introducing its first turning bezel of this sort. The 60 minute bezel being marketed as being particularly helpful to pilots timing action items.

In the catalogues I reviewed (all in OTD’s files), this is the first mention of a pilot-purposed chronograph. (Heuer’s catalogues were focused on all manner of other sports and motor racing up h til this 1962 catalogue.)

So here is Heuer’s first-mentioned pilot-marketed chronograph, and it’s the only watch in the 1962 (and 1963!) catalogue to not have the 3/6/9 emphasis marks (going back several years, the first to not have the marks - again, limited to those in the OTD collection).

ON THE WAY OUT:

Then a funny thing happens through the 1964-1966 catalogues: the prevalence of the 3/6/9 marks reverses, with only one model in the catalogue continuing to have the emphasis marks, and all other watches are “back” to standard 30 minute totalizers (with only 5 minute demarcations).

By the 1966 brochure, there’s not a single wristwatch with the 3/6/9 demarcation.

(OTD also has a 1968 and 69/70 “Chronosport” catalogues, with many examples of dive and other “tool” watches of the time, coming from many lesser and also well known makers - and from those catalogues only one chronograph the 3/6/9 emphasis marks.)


TAKEAWAYS (LIMITED TO OTD’s HEUER CATALOGUE LIBRARY):

Heuer never focused on pilot’s watches. The notable exception is the Autiva, starting in 1962, which had a minutes-counting bezel, but no 3/6/9 marks. (No watches in any year reviewed contained 15 minute totalizers, or totalizers showing only 3 minute increments - though many stopwatches did.)


Dispute this apparent lack of focus on pilot’s tool watches, almost every single chronograph had the “mere” 3/6/9 emphasis marks on otherwise standard 30 minute totalizers - between the years of about 1945 to 1964. (If on OTD had a more complete catalogue set, this could be better supported.)

So looking at Heuer only, given the lack of focus on pilot-marketing, the prevalence of the “mere” 3/6/9 emphasis marks for ~45-64 suggests those marks were viewed by Heuer as being relevant to chronograph users of all types. This supports the notion that the “mere” 3/6/9 emphasis marks were used (also used?) for something other than piloting - possibly the European-focused long distance telephone charge theory.

That said, not a single catalogue acknowledged the existence of the 3/6/9 marks, much less bothered to explain them.