[toi98uhn]

I own a similar clock (the Atmos clock mentioned in the article). It loses several minutes per month. FWIW, I live in Los Angeles and it has been the same regardless of time of year over the past decade or so. It's great that I don't need to wind it, and it's mesmerizing to watch, but it's not the most accurate clock in the world.

[zokier]

If it is consistently slow (or fast) then it sounds like it should be correctable; most good clockwork mechanisms have some way of adjusting the beat rate.

[op00to]

Indeed Atmos clocks do have a speed adjustment, though they are very sensitive. I'd contact a professional since any repairs to them get expensive very fast.

[wdfx]

I also have an Atmos. It is inaccurate to the tune of hours per day :( I have not yet taken measurements to find out which way it needs adjusting.