1001900 Storm Bottle for some FitzRoy Barometers also called Camphor Glasses, Storm bottle, 9 1/4" x 3/4" (body size approx 8 1/8" These glasses are hermetically sealed so will not dry out like old ones. The mixture is one from an original Negretti and Zambra recipe. As with many old ones the liquid may discolour (yellow) over time, this does not effect the rather doubtful 'forecasting' abilities as far as we are aware and may even enhance the look of an old instrument. Made for the UK , may not be so effective in hotter climates. We do not guarantee these at all, let alone to forecast weather! although we have often seen crystal patterns change this will greatly depend on position and temperature as well as outside influences - still a fascinating item. The size is general for many old barometers, we also sell the brass mounts for them.