The remarkable story of the discovery of Longitude by Dr Callahan

[dddave999]

Thank you for your synopsis of the John Harrison story. Just watched the series ‘Longitude’ produced by Selwyn Roberts in the UK. Your explanation finally made the penny drop as to how the problem was solved by keeping time. John Harrison would certainly be on my list of people I would like to have met. What an incredible man to have persevered not only to produce many timepieces, but also to battle against the establishment. What an inspiration he should be to inventors all over the world.

[zezfoe]

JORDAN!!!



[cyrustic]

cool! thanks for the tube.!!

[Teratornis]

8:03 - refers to 45 degrees of longitude as "the 45th parallel." But doesn't "parallel" refer to lines of latitude? Longitude lines are not parallel because they converge at the poles.

[ossumguywill]

@Teratornis They are parallel in non-euclidean geometry, because the earth is round and not flat.. We treat the latitudes as meeting at the poles because the compass will always point along these lines. It's just more convenient this way.

[pmh099]

Very nice but I have to add two details.

First, observing the noon sun with Greenwich time at 9am would place you 45 degrees EAST of Greenwich, not west.

Second, there is an additional correction to your longitude from the Equation of Time. This EoT is the known difference between the fictitious mean sun for which the equivalence between local time and longitude is true, and the real sun (whose noon you actually observe) which deviates from that ideal case.

[ChicaWolverina]

Pisspoor audio.

[johnplayer20s]

the rope with the log had knots tied in it at certain distances they would count the knots that were pulled off the boat by the log to judge thier speed thats where the get the measurements of speed of ships in knots/naughts

[villagefem]

Wow. Thats was too cool. what a fantastic way to learn....My boys will watch this piece and preferable Geo Thank you Sir.

[8220Mahmoud]

how did the seaman/navigator find the time using the "pipe" you mentioned ? Didn't the ship have any motions caused by the circumstances?? :s I'm really confused now..

[sdbaets]

Imagine a holow pipe. As you may know the sun is at its highest point in the noon (12 o clock) So that means that if the sun shines in your holow pipe and you see no shadow, the sun is "in the pipe" therefor at its highest point, so you know its 12. The movement of the ship is not an issue for example you could anchor(wich i don't think is necessary), and the smal motions caused by waves is no problem either(and no theres no storm else they wouldn't see the sun). Hope this helps, greetings.

[grasshopper00]

you definitely read Dava Sobel's book

[cannedlou]

I enjoyed your video very much.

Thank you.

Your direct presentation, your reference to the events and efforts leading to the final solution, and examples of the successful use of this old and fine art were a real treat.

It all really opens the imagination of past ingenuity and romantic adventure!

Thanks once again.

[ilaitianainoca]

best explanation ive heard so far......THANKS!!!!

[allenu]

Great explanation. Thank you!

[Valetudo21]

Very interesting

[alanhudsonesq]

Many thanks, I loved this video and talk that you gave here and I enjoyed it very much. We take time for granted now, but Harrison had to endure many hardships to make his time pieces - an incredible story in itself really.

[Beadbud5000]

Love his last sentence too! I am learning too...

[chitoblim]

thanks Learning

[froggybee13]

thanks we are learning about this is science

(yes i am that young 6th)

[watret]

thank you very much, very interesting.