BOOK It.] CONDENSATION. 657 



it), -when we condensed water (as was mentioned above), by 

 hammerinor and compression, imtil it burst out. For we ought 

 to have left the flattened globe untouched for some days, and 

 then to have drawn off the water, in order to try whether it 

 would have immediately occupied the same dimensions as it did 

 before the condensation. If it had not done so, either imme- 

 diately, or soon afterwards, the condensation would have 

 appeared to have been rendered constant'; if not, it would have 

 appeared that a restitution took place, and that the condensation 

 had been transitory. Something of the same kind might have 

 been tried with the glass eggs ; the egg should have been sealed 

 up suddenly and firmly, after a complete exhaustion of the air, 

 and should have been allowed to remain so for some days, and 

 it might then have been tried whether, on opening the aperture, 

 the air would be drawn in with a hissing noise, or whether as 

 much water would be drawn into it when immersed, as would 

 have been drawn into it at first, if it had not continued sealed. 

 For it is probable (or, at least, worth making the experiment) 

 that this might have happened, or might happen, because per- 

 severance has a similar effect upon bodies which are a little less 

 homogeneous. A stick bent together for some time does not 

 rebound, which is not owing to ar.y loss of quantity in the wood 

 during the time, for the same would occur (after a larger time) 

 in a plate of steel, which does not evaporate. If the experiment 

 of simple perseverance should fail, the matter should not be 

 given up, but other means should be employed. For it would 

 be no small advantage, if bodies could be endued with fixed and 

 constant natures by violence. Air could then be converted into 

 water by condensation, with other similar effects ; for man is 

 more the master of violent motions than of any other means. 



3. The third of our seven methods is referred to that great 

 practical engine of nature, as well as of art, cold and heat. 

 Here, man's power limps, as it were, with one leg. For we 

 possess the heat of fire, which is infinitely more powerful and 

 intense than that of the sun (as it reaches us), and that of 

 animals. But we want cold,' except such as we can obtain in 

 winter, in caverns, or by surrounding objects with snow and ice, 

 which, perhaps, may be compared in degree with the noontide 

 heat of the sun in tropical countries, increased by the reflectioi/ 

 of mountains and walls. For this degree of heat and cold cai 

 be borne for a short period only by animals, yet it is nothing 

 compared with the heat of a burning furnace, or the correspond- 

 ing degree of cold.' Everything with us has a tendency to 



» Heat can tow be abstracted by a very simple process, till the 

 degree of cold be ol almost any required intensity. 

 • It ii impossible to compare a degree of heat with a degree of oold, 



