Galileo's Liquid and Glass Thermometers 

They are also called "Termometro Lentos"  
which is Italian for: "slow thermometer" 

Searching for the exact temperature measurements the brilliant Galileo discovered this fascinating method. We think its because he got cold while outside at night using his other invention the telescope. Here's what he figured out. In liquid a solid body of the same weight and size is compelled to go down as the temperature rises. On the other hand the solid body goes up in liquid if the temperature falls. In these instruments the glass balls in the tube differ in weight and considering the density of the liquid you are guaranteed that the lowest of the floating balls in the upper part of the cylinder indicates the correct temperature. Each ball has a temperature tag on it so its easily readable.

The production of this instrument is extremely complicated. Any two glass balls differ in weight by only 6/1000 of a gram. Each cylinder is of solid glass construction with a wide glass base to present a low center of gravity to minimize the chance of tipping.

These make wonderful decorative conversation pieces and they fit in decors ranging from modern to antique. They are certainly eye catching and fun to own or make great gifts. Nobody is ever going to be unhappy receiving one of these!

All thermometers read in Celsius The floating bulbs in each of these are multicolored. The liquid inside the Galileo is clear and contains paraffin and petroleum distillates which are found in many household products.  Temperature spheres and thermometer body are individually hand blown by master craftsmen. 

Reading the Galileo thermometer:

Temperatures marked in Celsius

Bulb colors all the same  - Cobalt Blue Jet Black Emerald Green Bordeaux Amber/Cognac Purple Yellow.

Bulbs all on bottom: The thermometer is too warm. Display the Galileo out of sunlight and away from heat sources.

Bulbs split between top and bottom: The thermometer is working. The lowest of the floating balls in the upper part of the cylinder indicates the correct temperature. 

Bulbs all floating: The thermometer is too cool. Display the Galileo away from air conditioning vents or cold windows.

A simple fairly accurate thermometer today it is mostly used as decoration. The Galileo thermometer consists of a sealed glass tube that is filled with water and several floating bubbles. The bubbles are glass spheres filled with a colored liquid mixture. This liquid mixture may contain alcohol or it might simply be water with food coloring.

Attached to each bubble is a little metal tag that indicates a temperature. A number and degree symbol are engraved in the tag. These metal tags are actually calibrated counterweights. The weight of each tag is slightly different from the others. Since the bubbles are all hand-blown glass they aren't exactly the same size and shape. The bubbles are calibrated by adding a certain amount of fluid to them so that they have the exact same density. So after the weighted tags are attached to the bubbles each differs very slightly in density (the ratio of mass to volume) from the other bubbles and the density of all of them is very close to the density of the surrounding water.

The basic idea is that as the temperature of the air outside the thermometer changes so does the temperature of the water surrounding the bubbles. As the temperature of the water changes it either expands or contracts thereby changing its density. So at any given density some of the bubbles will float and others will sink. The bubble that sinks the most indicates the approximate current temperature.  

Four different sizes are available choose from: 

5 spheres in 2° increments from 18°C to 26°C.  Suggested Retail Price $57.00
11-INCH SLIM-LINE MULTI-COLOR GALILEO THERMOMETER      
(Thermometer Body is 1-1/2" Wide)

5 spheres in 2° increments from 18°C to 26°C.  Suggested Retail Price $63.00
11-INCH SLIM-LINE MULTI-COLOR GALILEO THERMOMETER      
(Thermometer Body is 2" Wide

5 spheres in 2° increments from 18°C to 26°C.  Suggested Retail Price $70.00
14 INCH SLIM-LINE MULTI-COLOR GALILEO THERMOMETER      
(Thermometer Body is 2" Wide

7 spheres in 2° increments from 16°C to 28°C.  Suggested Retail Price $89.00
17-INCH SLIM-LINE MULTI-COLOR GALILEO THERMOMETER      
(Thermometer Body is 2" Wide

Note: that we DO NOT accept returns of Galileo Thermometers/Galileo Weather Stations due to the chance of breakage during shipment. Galileo's that have been repacked often do not survive a second shipping. For that reason we do not accept returns on this item.