Geotec 341-3690

If you have read the page on this blog that goes into some of the variants of the "Versalog" slide rule then you will know that I have long had an interest in them. I have been a student of these for a long time, again thanks to Mr. Ted Hume, who got me hooked on these (addicted?? haha) and who was very instrumental in getting to the point where we are today, where nearly all the variants are well cataloged.

That is, all except one. The mythical all plastic, super late Geotec branded Versalog. Only one has ever been seen before, to my knowledge, and that one has no case, box, or anything else with it. But now that has changed, as in the first picture we see what we now believe to be the absolute beginning and the end of the Versalog story, as a second all plastic Versalog has been found! Finally, Alpha and Omega together.

The story behind this actually goes WAY back, years and years ago, to the time when the hobby was quite new, and a lot of discovery was still to be done. Many brands such as Keuffel and Esser had so many variations that it literally took a team of us to figure out the progressions and models. I still would not be surprised to see new K&E models show up even now! I was hard at work on the Relay/Ricoh slide rules, and perhaps readers are familiar with that body of work, and the website I had for years, now available on Webarchive. (See the links list for that and much more.)

Ted Hume and others were very much into the Versalogs sold by Post and manufactured out of Bamboo by Hemmi in Japan. The top rule in the first picture here is indeed the Alpha, one of the rare dual marked Hemmi 258/Post 1460 Versalogs, and this one has the date code "BA" which is January 1951. (See my article on Versalogs on this blog.) The variations went into like 19 distinctly differing types, the last of which was like a unicorn or the Loch Ness Monster, or Bigfoot. We knew it existed, but nobody could find one. Heck, the 258's are not common at all, but only ONE plastic Versalog had ever even been seen, and it was a Geotec (sold in Canada) branded rule. I wondered back then if I would ever see one, and it was at that time that I began looking at EBay EVERY DAY to try to find one. Literally every day for perhaps eight or ten years. I was starting to believe the stories that the one seen was only a prototype and as such was one of one made. Until last week.

Here are a couple of pictures shown in the auction, which I won. There were only three pictures!! I will tell you right now that it was like 22 bucks INCLUDING SHIPPING, with only two other people bidding against me. Unless you are up on your scale sets, and/or very familiar with "standard" late Hemmi plastic slide rules, this could have gone unnoticed. Or perhaps nobody is left who knows of it, perhaps the myth of its existence faded into the past as so many myths do, when no proof of them ever surfaces. Whatever the reason, I almost had a stroke when the auction ended at the price it did. Needless to say I had protected against MUCH higher last minute sniping!! (Click on most pictures for enlarged versions you can study.)

 As you can see from the pictures, the box is totally conventional for a late Hemmi Duplex slide rule, whether plastic or bamboo. But the weird case and rule itself are a dead giveaway that this is no ordinary late Hemmi slide rule. For one thing, the colors and pattern and details of the case do not match other known late Hemmi cases. Also, the rule itself should raise an eyebrow.


Typically, the two piece pull apart plastic cases (A type which I have grown to love, as opposed to the VERY nice leather cases furnished with many Hemmi slide rules) are blue and a sort of off-white, with the lid or smaller piece being blue. Another thing is that the "usual" Hemmi plastic cases SAY "Hemmi" on them somewhere, on the end or the sides of the larger piece of the case, often both. Also the finger grip indentations are all wrong. The top picture in these is a screen grab so you can see I actually paid almost nothing for it. The next two pictures, also ripped from the auction and rotated 90 degrees here, are the dead giveways that this is indeed the long sought after Geotec 341-3690 Versalog. We cannot see the side of the slide rule that actually has this designation on it in ANY of the pictures, but from what we CAN see, it is obvious if you take into account the already noted oddities, and the scale set. Look closely at the picture out of the bag (yes it was still sealed when the seller found it, they opened it to take the pictures!) and you will note the scale arrangement on the "back" of the rule. Students of the Versalog must instantly recognize this to be the later "Versalog II" set, which added an "A" scale and put the "L" scale on the back side, and which also changed the degisnation of the "ST" scale to "SRT" which is interestingly the same designation K&E used on their late slide rules.

Also, look at the scale range designations on the right end of the slide rule. These are another dead giveaway that this is a Versalog. (Interestingly, NO "Versalog II" ever said "Versalog II" on it, they only say "Versalog", whereas the manuals and boxes and ephemera does in fact call out the newer expanded scale set of the Versalog II.) K&E was another company that liked to have range data on the right end of the scales, but Hemmi did not, at least not on their own rules of their own design. We will not go too far down this road though, because then we would have to discuss how the Versalog even came to be, which is a great topic but beyond the scope of this initial article. Suffice to say that this side of the rule is sure proof that what we are looking at here has a "Versalog II" scale set, and therefore must be the mythical Geotec (Hemmi) 341-3690.

So, after all these years one of these has finally surfaced. Just like the long sought after K&E Doric 10000/10002 slide rules, now this beast is no longer just a rumored to exist slide rule of yore. Coming up in part II of this article, we will go into an in depth study of this legendary slide rule, from a manufacturing and marketing standpoint, and try to unlock any of the secrets that may be had by thorough examination and comparisons of this and other late slide rules.