256 SEC. 8. HEAT. 



1087. Model of Circular red hot Copper Railway, for 



causing a metal ball to rotate by means of unequal expansion by 

 heat. George Gore, F.R.S. 



Model in wood of circular railway, which when formed of copper heated to 

 redness, and a thin cold ball of German-silver placed upon it, the ball rotates 

 by the influence of unequal expansion produced by the heat. ( See Philo- 

 sophical Magazine, August 1859.) 



III. THERMOMETRY AND PYROMETRY. 



Air Thermometer, in the form first given by Galileo. 



The Royal Institute of " Studii Superiorly Florence. 



Padre Benedetto Castelli, one of Galileo's disciples, writes about the ther- 

 mometer as follows : " I recollect an experiment shown me, about the year 

 " 1603, by our Sig. Galileo. He took a glass bottle of about the size of an 

 " egg, having a neck nearly two palmi in length and as thin as a wheat 

 " straw, and having warmed it well with his hands, he then turned its mouth 

 upside down into a vessel placed underneath in which there was a little 

 water. When he had removed his hands from the bottle the water began 

 immediately to rise in the neck, and mounted higher, by more than a palmo, 

 than the level of the water in the vessel. Sig. Galileo made use of this 

 effect to construct an instrument for examining the degrees of heat and of 

 cold, concerning which much might be said." 

 And then Vincenzo Viviani, another disciple of Galileo's, in the life of that 

 great man, which he wrote between 1593 and 1597, states that Galileo 

 invented the thermometer. 



1828. Registering Thermometer of Fontani. 



The Royal Institute of 11 Studii Superiori" Florence. 



Thermometer, cinquantigrade, with spherical bulb. The 

 freezing point corresponds to 13 "5. The academicians used this 

 thermometer for the meteorological observations instituted first 

 by them in 1654. Accademia del Cimento. 



Thermometer, cinquantigrade, with cylindric bulb. The 

 point of ice melting corresponds to 13 '5. 



Accademia del Cimento. 



Thermometer, settantigrade. The freezing point is at 23 5. 



Accademia del Cimento. 



Thermometer for bath. When immersed in the bath it must 

 indicate 49, as is written in the upper little ball. 



Accademia del Cimento. 



Thermometer, with foot divided in 470, corresponding to 

 26 centig. It served for the experiment made to ascertain 

 whether the cold of ice reflects itself from the mirror like the 

 heat of burning coals and light. Accademia del Cimento. 



Thermometer, with elaborate foot. An object of art. 



Accademia del Cimenta* 



