Surveyor's Compass

This reeks of homework.

The compass you are asking the question about has a mirror that you read the compass with as you look through the sights,thus the image is reversed. If you try to read the compass directly the East and West appear to be bassackwards.

Hunter

It's not because of the mirror. The compass on a 4 post surveyor's transit reads the same (no mirror). The reason is simple. The needle always points to magnetic north. Stand behind the compass facing north. Turn to your right to face east. The needle is pointing to east on the face of the compass. Turn to your left to face west. Now the needle tells you that you are facing west. For some reason toy and amateur compasses label the cardinal directions of a map. They do not indicate the true direction you are facing.

Guest (Hunter), I thought this was a riddle...

a picture is always worth 1K words.

Do you mean the Circumferenter, an old surveying instrument ?

a big GA, with which I eat my own words.

Randall,

an excellent explanation and description.

I have an old Brunton style compass, made by a company called NAUTICALIA.

This one has adjustnments for both variation and declination but is difficult to use and may require cleaning of the mirror and glass - all of these compases require a stand to get any accuracy out of them.

The site description lets us down in one tiny area, the labelling of its parts is a terrible colour for my ancient eyes!

Is there any access to read further, I can try and borrow the books from our libraries but I am looking to copy material for my own use.

Thanks very much

Sleepy

Hi Sleepy,

This could be what you are after http://www.brunton.com/manuals/current/Compasses/Transit.pdf

Cheers, Bob

Hi AusieBob,

Thanks for that, I have an very abbreviated version of that so that was great contribution to my pesonal files.

My next priority is to look for a tripod or tripod adaptor!

Thanks again for that input, it was very useful.

Sleepy

This is not the only compass that is confusing.Back in the 1890's during the gold rush to Alaska, there was a watch company that made excellent railroad watches.They decided that they could cash in on the current frenzy of travelers if they also sold a compass.As a matter of economy, and to gain a marketing edge,they decided to put the compass on the back side of the watch, thereby having two instruments in one.The TATE WATCH COMPANY sold thousands of these watches,however, they did not fully understand the principle of the compass.The clock hands interacted with the compass heading, and according to the time of day when you looked at it, you would get a different bearing.

We all owe a great debt to this company, because previously unsettled parts of the US were settled because people simply got tired of wandering.Women got pregnant,had to stop for childbirth,etc.Then it became too difficult to travel any furher, sot they simply settled down where they were.Only a small percentage ever made it ot Alaska.And is is still sparsely populated even today.

And to this very day, a saying from that era is still familiar:"He who has a TATE'S is lost"

EZStreet( AKA:FullaBulla)