Recent Comments

1. about 15 years ago on Pluggers

   I recently broke and dislocated both elbows (at once!) This threw into sharp relief the problem of child-proof caps.

   I have grandchildren. I have children. We have protocols to keep medicine out of reach of young’ns. That’s really more important than child-proof caps, which, in fact, I was getting help from my children and grandchildren to open for a few weeks!

   My health insurance works with a prescription-by-mail company, which allows child-proof or easy-open caps. I got the easy-open caps on all my latest prescriptions, and by is that an improvement.

   So: meds protocols: A shelf over 5’ above floor level in a closet with a latching door that can be closed. A plastic box (open or closed) taller than the meds bottles, so they’re just not visible to the littles. And most important, training the small ones to recognize pill bottles and understand that they are not toys, not candy, not to be taken unless they are a) yours and b) given to you by your parent.

   It’s not hard to implement, and it works very well. A child trained to understand that medicine is serious business goes from liability to asset, especially when grandpa breaks both his arms at once!

2. about 15 years ago on Pluggers

   You can still buy sliderules!

   New ones are still made by a Japanese company called Concise: they are circular. They have a couple of models which are real sliderules (logarithmic-based scales, cursor) and a few others which are more nomograms or slidecharts.

   You can find old sliderules, some “old new stock” in original packaging, on ebay all the time. There are also books on archive.org and books.google.com that tell how to use them, and at least one mailing-list group, groups.yahoo.com/group/sliderule which is populated with sliderule users and collectors.

   You can still use sliderules: Most of the teachers remember them, and will allow lower precision answers (two or three significant figures, generally) done on a rule instead of full-precision (often meaningless precision) answers from a calculator!

   Sliderules are wonderful: they are a physical embodiment of calculation, generalized to universal application, or in other words, you can calculate just about anything with the right rule. Specialized rules included scales for particular jobs (electronics, RFdesign, surveying, chemistry, etc) but even the simple Mannheim rule can do squares and roots, multiply and divide, figure ratios, and do both chain calculations and series of ratios with ease. Add trig scales and log-log scales and you can do any power and solve amazingly complex problems.

   What you cannot do with a slide rule is add or subtract (although there have even been rules with linear scales made for that purpose!) But since the scales lend themselves to approximation, rather than great precision, they encourage a sense of proportion and estimation and relation to the Real World. (Woodwork, for instance, can be done to .0001” with modern computerized routers, but wood swells ~1/32nd inch with mild humidity changes, so who needs more accuracy?)

   The reason you don’t add with a slide rule is because it is already adding, but adding logarithms. (Remember the joke about the snakes on the Arc? God said “Be fruitful and multiply,” but they couldn’t: they were adders. So he had Noah make a log table, and then they were alright! Add logs to multiply!) That’s why the A/B and C/D scales are not linear: they represent the log values of the printed numbers in distances, and you use the slide and cursor to add or subtract the distances to multiply or divide the numbers. It’s even easier to do than to describe!

   Just about every trestle/suspension bridge in the country, along with nearly all the great multistory buildings, ships (prior to about 1976), aircraft, etc and most of our space efforts were built on calculations done on sliderules! High-precision calculations were made only when needed on expensive large computers. Calculators have turned that upside down, though, but sliderules could and should still be taught in schools. (OK, I’m off the soapbox now!)