Hopefully wolfy will see this post.  He knows a lot about compasses and may know about this one.  I had one Silva for years but it is long gone.

Looking at Silva history the company started around 1933.  One of their early achievements was a compass that settled in 4 seconds thus the 4S designation perhaps. 

They started US production in 1946.  There have been some for sale on various Ebay sites in Australia, Europe, and the US but none are currently listed.   

So an update!  Tractor is running pretty good.  I did have an issue with the idler pulley tension tab for activating the clutch.  When coming to a stop and going to shift to another gear, manual trans, it would grind as the drive pulley would still be spinning.  Would have to wait 5-10 seconds for it to stop spinning.  Had to add an extra tab but it did the trick.  Original was welded on so couldn't adjust or remove it, there was enough clearance though to just add another in more forward position.  Now when pressing clutch pedal in it stops the belt instantly, like it should.  So my use plan for this rig is to be a tow/puller logging rig.  Ordered a 2" front hitch receiver.  Pretty handy so now I can use any 2" hitch in the front.  Will plan to add one to the back at some point.



Taking it for a spin in the woods





here is the front hitch receiver with a tow hook in

This compass belonged to my grandfather, and I'm curious to find out approximately when it was made.  I sent an email to Silva to ask about it but they couldn't find anything about a Type 4S and the best they were able to do was send me the manual for a Model 54, which seems to be a fairly close modern equivalent.  Like the 54, The 4S has a small mirror and a sighting lens in the bezel which gives the functionality of a sighting compass.  It has fewer markings on the base plate than the 54, and the scale at the top of the base plate is interchangeable.  Also, where the 54 has a clear plastic disc in place of a needle, the disc on the 4S is aluminum. 

I don't have a place to upload photos that would let me post them inline here, but I think these links to Google Photos should work:
Overall view of compass: https://photos.app.goo.gl/H4WQvPofZdsrqHVMA
Close-up of markings: https://photos.app.goo.gl/WNovnYWyqPQA4cxG7
View through sighting lens: https://photos.app.goo.gl/DrNHPghjE49oemxA9

I thought maybe the combination of the plastic bezel and the aluminum compass rose disc might help narrow down when it was produced, if anyone happens to know when the transition from aluminum to plastic might have occurred. 

I'd be grateful for any thoughts anyone might have about this compass.

Thanks,
Ben

Isn't this the time witches run naked through fields of lilacs and daffodills?

 They do around my area, not so much in Salem anymore, but they are pretty active in the Freetown MA. state forest, there used to be some pretty serious shenanigans going on there years back, but it's calmed down considerably since they stopped doing human and animal sacrifices.   

Mot sure that's a good idea today or any day. I don't know much about witches, although years ago one coworker claimed to be one, but it would likely be traumatic for the game. Might look good on some folks however.

The whole Wiccan thing will have to get along without me.

If you decide to hike today don't forget a trip report.