ABSTRACT
The barometer on shipboard should be suspended on a gimbal frame, which ought not to swing too freely, but rather so as to deaden oscillations by some degree of friction. The instrument should be suspended out of the reach of sunshine, but in a good light for reading, as near midships, and in a place as little liable to sudden changes of temperature and gusts of wind as possible. The light should have access to the back of the tube, so as to allow of setting the index to have its lower edge a tangent to the convex surface of the mercury. In placing the external thermometer, an exposure should be chosen perfectly shaded both from direct sunshine, and that reflected from the sea, or radiated from any hot object. It should be especially guarded from rain and from spray, so that the bulb should never be wetted, also from warm currents of air and from local radiation.
