Rare Vintage Boxed Hydrostatic Bubbles and Bakelite Thermometer

A true rare find - Boxed set of four hydrostatic bubbles with instructions and bakelite thermometer.  The box consists of 4 glass bubbles, green, red, amber and blue.  In the front of the box there is a card stuck in the front indentation with directions of each colour.  Each colour has a relevance to temperature.  The bakelite thermometer has its own groove at the back of the box.  Once removed there are the directions for use :  Directions for use - Nearly fill a small wine glass with Spirit, stir it with the thermometer, and raise the Temperature to 60deg or 70deg by the heat of the hand round the wine glass, then immediately drop into the glass the proper Tester for  the Temperature and Strength of the Spirit you are Trying.
The thermometer is constructed of bakelite with brass fittings and a mercury base.  It has a string inserted for easy handling.
Condition : Good antique condition with some wear commensurate with age and use.  A water mark can be seen on the inside of the case.   Age approximately between Edwardian and Art Deco.
Great gift for the wine makers, wine connoisseurs,  bar owners, spirit merchants........ just to name a few
Dimensions: 
Weight : 98gr
Length of case  :  14cm /140mm/5.5inches  ** nice and compact - could fit in a jacket pocket for those wine tasting tours.
 
Footnote : 
Antique or vintage items have been used and as most antique dealers would say "PRE-LOVED", they will show signs of wear which is  commensurate with age.  Now this will appeal to some as it authenticates it's age.  
I will always try to list all faults found with each object to the best of my ability and photos form part of the illustrative narrative.
All vintage used items are sold "as is" . If in doubt please ask questions before you make your purchase, I am always happy to answer and send additional photos if required.