Book Review: Longitude

[Savago]

Last week I got from Amazon the book titled "Longitude: the true story of the genius that solved the greatest scientific problem of this time" by Dava Sobel.

It tells the story of John Harrison's watches (he was recently featured in a Google doodle, check: https://en.wikipedia.org/wiki/John_Harrison) and how they solved the practical and strategic problem of calculating the Longitude of ships back in the 18th century.



The book is literally a page turner: I started reading it last Friday 22:00 and finished around 2:00 (with a few breaks for tea and looking in wikipedia for further information on a few of the mentioned historical figures).

After a terrible ship wreck that costed the lives of over 5000 soldiers, England's parliament offered a 20,000 pounds prize to whoever solved the problem of longitude calculation in 1714.

Harrison was a carpenter who self-learned watchmaking and worked for 30 years to make a watch that could resist the challenges of travelling in high latitudes facing changes in temperature while keeping a precision of less than 3s gain/loss per day (the book explains how anything less precise would yield a big longitude positioning error).

He presented to the Longitude Board (that had scientists like Isaac Newton in his ranks) a series of watches (H1, H2, H3) that were improvements in both precision and size/weight, building up to his master piece the H4:


The H4 took 6 years to construct and made his maiden journey aboard the 50-gun HMS Deptford from London to Jamaica under the care of Harrison's younger son William in 1761. After the 81 days of journey, the watch allowed the longitude calculation with an approximate precision of one nautical mile.


A clear winner, right? Well, the Greenwich astronomers that were part of the board didn't think so and would make more requirements and give Harrison years of trouble for him finally being able to receive (part) of the prize, only after interference by the King George.

I won't provide further spoilers, but this is a story that is really fascinating and worthy learning more (both from a historical point of view as also for anyone that appreciate mechanical watches).
 

[The emperor has no clothes]

Thanks, I’ll see if I can get it in audiobook for my ride to Inzane. 

[Savago]

Forgot to add the link to the book:
https://www.amazon.com/Longitude-Genius-Greatest-Scientific-Problem/dp/0007902506/ref=sr_1_7?ie=UTF8&qid=1525465207&sr=8-7&keywords=longitude+book

[Gryphon Rider]

Haven't read the book, but A&E made a movie of it that is excellent.

[f6john]

People like that always makes me a bit dim witted.

[bentwrench]

Solving the longitude problem was on par with the printing press and powered flight in the last 500 years of history.I first read that book while ocean sailing on a friends sailboat.learning to use a watch and a sextant really brought me closer to that well written story.

[Patrick]

Its a really amazing story.

[RDKLL]

I have seen the A&E movie and just reserved the audio book thru Overdrive app

[The emperor has no clothes]

People like that always makes me a bit dim witted.

Nah...they are just extra witted. 

[Alpha Dog]

Haven't read the book, but A&E made a movie of it that is excellent.

Indeed. I watched the original series.  Very good.

[0leman]

Timing was everything in the days before GPS in determining your location using the sun. 

I spent a few weeks using a transit, a good watch (actually a Timex), book of solar tables, and the sun to determine our exact location.   Needed it for the a easement we were trying to obtain.  Lot more accuracy than folks in Harrison's time.

[hubcapsc]

It was technology like this that allowed us (Europeans) to project military
power across the globe and pretty much take over everything for a while...

-Mike

[Jess from VA]

My dad was an ace civil engineer, and I remember him using his sextant shooting the sun when the family sailed across Lake Erie a few times.  It was one thing if you had a favorable wind, and could set the sails on a single tack (on a known compass course) across the lake, but another thing if you had to tack upwind back and forth all day (and into the night) to get across the lake.  (sextants don't work at night)

The other thing he did that amazed me (as a kid), was some local neighbors got in a dispute about an addition one of them was adding.  The local rules would not allow you to do many things (on lakefront property), and one of them was you couldn't build any structure out front that would cast shade on any part of your neighbor's property (beyond your existing house).  Dad got out his sextant, and slide rule and a book, and after about an hour, he said the proposed structure (blue print only) would never cast any shadow on the neighbor's property, regardless of the month or season and variable angles of the sun throughout the year.  

I could not understand how he could do that (and I still can't).  He assured me if I kept studying my math, I could figure it out too.  Math was never my best subject.

Here was our Pearson Electra I grew up sailing. (Midget ocean racing class, so very seaworthy.) I was a good deckhand or helmsman, but not trustworthy as a navigator.


   

[Savago]

@0leman: crazy to think that any 50 bucks quartz watch today will beat the crap in precision of all expensive mechanical watches no mattering the brand.

@Jess: awesome photos and report!

[0leman]

@0leman: crazy to think that any 50 bucks quartz watch today will beat the crap in precision of all expensive mechanical watches no mattering the brand.

@Jess: awesome photos and report!

I had the advantage they didn't have.  I could set my $30 quartz watch first thing in the morning before going out. These guys on ships didn't have that convince.   We did the measurements before 0930, later in day it was harder to measure the sun.