Hi Robert,I wouldn't want to commit to suggesting how many Graphoplex would be worth making. Possibly as few as would provide a challenge!I raher like the Graphoplex 691a with ...

In my last message about Delamain's "Grammelogia", I reverse engineered the two circular slide rules illustrated on the title page and second page. I mentioned a third slide rule figured ...

Hi Robert,for elegance vs. usefulness I'd have an opinion. Useful is what allows calculations with the least number of settings and elegance is what allows for usefulness with the least ...

Hi Rod,Thank you for your kind words.Two questions:1. How many Graphoplex replica do you think would be worth making? And which one do you think is the most prominent? I ...

Yes, a couple of years after that I supplemented my Pickett N4-T with a Bowmar four-function calculator ...

What about a Thacher?/

Hi Robert,You have the most remarkable collection of emulators/simulators/replicas I have ever seen.I am in awe of the expertise shown here.However, I wouldn't want you to rest on your laurels!!There ...

Dear All,It took me a while to code Pickett N909-ES.The problem was the conversion scale.But finally it is done and sitting on http://www.sliderules.org .Apart from Pickett N909-ES replica, there are ...

I saw that! Yes, I'm afflicted by both the slide rule and the amateur radio past times. Ah - 1970. That would be just a couple of years before "The Fall", aka ...

Fred,Yes, Daniel had a copy. Many thanks. I had also sent a similar request to my librarian sister!Wonderful how helpful this group is.Tom Wetmore

Tom,Does this mean you do not need to find another copy of Delamain's work?I have put in a request to my go to mathematics librarian.  Should I tell her that ...

Daniel Say graciously sent me files showing three different circular slide rules diagrammed in Delamain's "Grammalogia". The different editions of Grammalogia date from 1630 to 1635. Oughtred actually invented the ...

Thanks for the notice. I dug through and actually have that issue. ...

For those of you who are radio amateurs and who have access to QST magazine, see page 93 of the March, 2020 issue.  It's a reproduction of the cover of ...

FYI, Florian Cajori edited a very short selection from Delamain in David Eugene Smith, A Source Book in Early Mathematics, vol. 1 (New York: Dover, 1959 [reprint of 1929]), pp. 156–59.  Cajori was ...

I keep my slide rules (other than really long ones) in a cabinet built to hold insect specimens — 40 drawers. Works like a charm. Got it cheap because no ...

E. Dean,Wow! I am so covetous of your collection! There must be some wonderful stories to be told on how it came to be.I have four cardboard boxes used to ...

Hi Tom:What you are doing is very interesting and very much aligned with my own slide rule interests.Like you, I tend to focus on very early rules and the more ...

E. Dean,Thanks for contacting me. I am in Massachusetts, USA, close to a Cambridge, but not the right one!I have a lead on getting an electronic version of "Grammelogia" from ...

Tom:Where are you located? Certainly the Cambridge library will give you access to their copy — if you can get to Cambridge.Do you intend to publish the work you are ...