I have a glass hydrometer that I bought used from an old beekeeper in town. He told me that he paid $40 for it 20? years ago - so I assume that it is a decent one. Anyways, my question is that it is calibrated for 68 deg F. However I quite often want to check honey at different temperatures. Say for example - in the double boiler at 120 deg. Is there some way to figure out a correction factor for other temperatures? Are these things accurate that far away from the design temp?