Field Equipment: Pocket Compasses

[Atlantia]

Originally Posted by M ELEY

Very nice specimens, gents. I've always wanted to pick up one of these for my "nautical collection", for although sextants were the tool of choice, compasses also served on many a merchant/privateer vessel. I like to see these related items in posts since they serve to support the study of military life. Just picked up an old maritime telescope myself recently, made by Spencer, Browning and Rust, ca. 1800. Thanks again for posting these.

Just wanted to add how nice it is when you manage to find a telescope of that age (my Dollond is around then as well).
Very nice items, hugely expensive in their day, and of absolutely vital importance especially to mariners.
I won't mind at all if you post pictures of it

[fernando]

Hi guys,
Little antique curious stuff is my middle name .
May i introduce a less austere little device... just for the fun .
An old wood handmade Compass + Sundial, of reduced dimensions (less than 3x2") and weight (aprox. 1 ounce).
I like the artist's naive presumption to tag the thing with REGISTERED MARK and made by the REAL AUTHOR named JOÃO DA SILVA.
Well, it might not be an accurate guiding tool, but certainly a rare object .
Allright, don't hit me; i just couldn't resist showing this little thing.
Fernando

.

[Atlantia]

Originally Posted by fernando

Hi guys,
Little antique curious stuff is my middle name .
May i introduce a less austere little device... just for the fun .
An old wood handmade Compass + Sundial, of reduced dimensions (less than 3x2") and weight (aprox. 1 ounce).
I like the artist's naive presumption to tag the thing with REGISTERED MARK and made by the REAL AUTHOR named JOÃO DA SILVA.
Well, it might not be an accurate guiding tool, but certainly a rare object .
Allright, don't hit me; i just couldn't resist showing this little thing.
Fernando

.

Hi Fernando,
What a Charming little instrument! I just love the decoration. Especially the 'Sundial' numbering inside the case!
The way it has been put together actually reminds me of victorian 'Ouija Boards'.
LOL, hope it IS pointing to north, and not a 'spirit compass'
Its lovely Fernando, any ideas of age?
Regards
Gene

[fearn]

Hi Fernando,

Amusing little instrument, because Silva (link) has been making compasses since 1928. In Sweden.

I'm not sure whether yours is older or younger than that.

That said, does your device actually work? Does the compass point north? If the sundail was supposed to be accurate, the angle between the string (gnomon) and the base should be roughly the latitude for which it was manufactured.

Best,

F

[fernando]

Now, i've got myself into troubles; i forgot these guys want to know everything .
The Swedish Silva is just a coincidence; the name Silva is one of the oldest Portuguese family names.
I would swear this João da Silva was from Braga, a city here in the north, but i don't remember where i have read this. Searching the name per se is useless, as it is so vulgar as John Smith.
But in any case this little device is local handcraft. Amazingly, not necessarily being a 'sworn' apparatus, it does point (shamely) to North and, going out to the veranda i positioned it in the North ditrection and it indicated the right time over here: 5 pm it was.
Hard to tell its age; thirties or most possibly earlier. I wish i traced some other example i saw illustrated somewhere, which i think once happened.
Fernando

[fearn]

Thanks Fernando.

Nothing shameful about it--if it works, it works, and that's the most important thing any compass can do. I was concerned that it was supposed to be a cheap ripoff, but simple as it is, it was properly designed and built.

F

[fernando]

Hi Fearn ... and others,
Urgent correction to my lousy english .
I meant shamely, as it hesitates a bit before it points north; probably missing some of its original magnetic load.
Fernando

[kronckew]

i have always been fascinated by sundials.

i frequently use the one in my garden as a backdrop for my blade photos. i use a simple flat dial with a gnomon set at the local latitude angle.

here shown upside down as the blade is the star.

i used to have an armillary sphere there,

but it was a bit hard to read. lives on my window sill now. i also have a sheperd's stick sundial like this one somewhere:



Also known as a Pillar Dial, this is one of the earliest and most widespread forms of sundial. To use, the folding gnomon is swung around to the correct position for the time of year (the months are indicated by letters around the base). The sundial is then suspended so that it hangs vertically. The shadow of the gnomon then falls straight down and ends somewhere between the hour lines. Each line represents either an hour of the morning or afternoon, as it works by plotting the rise of the sun till noon and its subsequent fall. This type of sundial is specific to a particular latitude, and this one is set for a latitude of 52 degrees. Originally carved in ivory, bone or wood, this example is cast in resin with pewter fittings.

another is the more futuristically modern all plastic optical one here:



the gnomon is actually a circular acrylic prism that focuses the sun into a pointer along the dial. it has an inbuilt spirit level, compass and angle adjustment as well as a vernier for adjusting the equation of time corrections. the dial rotates like an old circular slide rule to allw compensation for time zones. all fits into itself for travelling. it is accurate to the minute.

and finally, here's one i made earlier: these are called diptych dials



very similar to the 'da silva one above, but tells time on both the horizontal and vertical parts. the string is set at a general angle for the latitude, but you can adjust by trimming the base to compensate for your precise latitude if desired.