Obs. rare. [mod.L. use of L. stagnum pool.] The mercury-cistern of a barometer.
1705. Addison, Italy, Antiq. near Naples, 232. I borrow’d a Weather-glass, and so fix’d it in the Grotto, that the Stagnum was wholly cover’d with the vapour.
a. 1734. North, Life Ld. Keeper Guilford (1742), 293. This must draw down the Tube into the Stagnum, till so much of the Glass Tube is immersed, as shall answer that Encrease of Weight.
