ON INSTRUMENTS FROM ITAL Y. 141 



on which it floats. Now the academicians by means of intelligent 

 and varied experiments, clearly set forth, that as a matter of fact 

 water by freezing increases in volume, so as to rend in pieces the 

 vessels in which it 'is contained, and they proved, at the same time, 

 that the bursting of the vessels is not to be attributed to the formation 

 of a vacuum, but solely to the dilation of the contents. In this way 

 they caused the bursting of balls of the thickest glass, and of brass, 

 and of copper, and of silver, and of gold. They also determined the 

 relative expansion of ice and water, which they established as 9 : 8. 

 Then the experiments made to investigate even in its most minute 

 details the act of freezing are marvellously interesting, clear, and 

 precise. 



Here are these subtle observations and their classification ; and I 

 leave you to judge whether at that time, or even in our days, I was 

 about to add, more could be done. They used for these experiments 

 balls of glass ending in long tubes ; they were filled with water and 

 then immersed into a freezing mixture of salt and ice, to which they at 

 times added a sprinkling of alcohol (aquarzente). The natural state 

 means the degree of temperature of the water or other liquid in the 

 tube of the vessel before it was placed in ice. " Salto dell' immersione" 

 is that first rebound which the water is seen to make the moment 

 the ball touches the ice. This does not come from any intrinsic 

 alteration of the water, but from extrinsic reasons of the vessel. 

 Hence it is that it sometimes varies slightly, and thus brings about 

 some change in the other conditions through which the liquid passes 

 before freezing. But as that leap altogether is but very little, so ar 

 its variations but very slight, and infinitesimal are the effects which it 

 produces in the subsequent changes. "Abbassamento" denotes the 

 degree to which the water, after the above-mentioned salto dell* im- 

 mersione, descends when the cold is beginning to affect it. 



" Quiete" is the state in which the water remains for some time after 

 the dbbassamentOy without showing any apparent signs of motion. 



" Sollevamento" is similarly the state which the water from the 

 lowest point of abbassamento attains by means of rarefaction, with a 

 very slow and apparently equable motion (in all respects like the first), 

 with which it contracts itself. 



" Salto delP agghiacciamento" means the state into which the water 



