Three questions in one! Speed/Distance and rank.

Post by **DaveK** » Tue Jul 29, 2014 6:14 pm

There are some really good 'for the layman' books out there though

Post by **Marvin** » Tue Jul 29, 2014 11:05 pm

And some of them were written by Isaac Asimov.

Post by **DaveK** » Wed Jul 30, 2014 8:13 am

The man was a genius and one of the small core of writers who made me an ardent SciFi fan half a century ago. (LonCon in a couple of weeks time

)

I've just managed to get a copy of his 'An Easy Introduction to the Slide Rule'

It's rarely available on the market! This one is ex-Whatcom County Public Library

Post by **Marvin** » Wed Jul 30, 2014 3:48 pm

The slide rule. It's amazing how so many sci-fi writers thought they'd still be in use in the 21st century.

Post by **DaveK** » Wed Jul 30, 2014 5:15 pm

From post: 172173, Topic: tid=8712, author=Marvin wrote: The slide rule. It's amazing how so many sci-fi writers thought they'd still be in use in the 21st century.

They are still used, though more in the developing world where batteries aren't easily available. There are still many specialised 'slide rules' available like 'load adjusters' and slide rules for machining, hydrodynamic flow through pipes and even flight 'computers'. They remain in use because their individual scales can be created to allow the setting a complex equation with one variable and several constants with just one movement of the cursor without having to run through the multipart equation each time!

A couple of the top end Faber Castell models are still manufactured in Brazil.

A friend of mine (a slide rule collector and a keen juggler) created a couple of slide rules for calculating juggling movements - you set the number of 'balls' and the basic sequences and it let's you read of the manipulations and changes needed - or even see if the combination you want to try can actually be done. Doing it all by hand using trial and error is difficult unless you're very very experienced, especially if the sequence is actually impossible unless you're an octopus!

But I digress . . .

Post by **Marvin** » Wed Jul 30, 2014 5:49 pm

I never met a slide-rule algorithm that couldn't be programmed into a hand-held calculator. As far back as the mid-1970s, our aircraft commander's hand-held calculator computed Hc and Az of celestial bodies in about the time it took to read off the data from an Air Almanac ... leaving me in the dust while I laboriously did the same calculations using H.O. volumes.

But, I digress. My originally comment was directed at sci-fi writers who, while they could dream of big things like space ships, hyper-space drives and colonies on other planets in the galaxy, still thought in terms of slide rules ... and cigarettes.

Post by **DaveK** » Wed Jul 30, 2014 6:21 pm

From post: 172177, Topic: tid=8712, author=Marvin wrote:I never met a slide-rule algorithm that couldn't be programmed into a hand-held calculator.

EE 'Doc' Smith's Lensmans Series: Future technology would be much better so wires needed to be metres in diameter to handle the enormous currents for the starship drives and weapons. Engineers still would use slipsticks though!

The operative word is 'programmed'. A specialised slide rule could be given the the guy operating the lathe and he could use it easily. Plus calculators were very expensive then plus they are not as robust as a plastic slide rule plus they need a power supply.

I nearly got fired in 1971 for breaking the four function reverse polish 8 digit mains powered calculator that cost $300 then! I was earning $1000 per year (Â£Â£ equivalent!)