208 HISTORY OF COLD AND THE ABSOLUT?] ZERO. 



it in deep Ciives or hig-h mouiitiiiiis, and when all is done wc can not 

 obtain it in any gTeat degree, for furnaces of fire are far hotter than 

 a summer sun, but \'aults and hills are not much colder than a winter's 

 frost." The great Robert Boyle wa ; the first experimentalist who 

 followed up Bacon's suggestions. In 1()82 Boyle read a paper to the 

 Ro3"al Societ}' on "New experiments and observations touching cold, 

 or an experimental history of cold."' pul)lisbed two years later in a 

 separate work. This is really a most complete history of ever^/thing 

 known about cold up to that date, but its great merit is the inclusion 

 of numerous experiments made by Boyle himself on frigorific mix- 

 tures and the general efi'ects of such upon m.atter. The agency chiefly 

 used by Bo3'le in the conduct of his experiments was the glaciating 

 mixture of snow or ice and salt. In the course of his experiments he 

 made many important observations. Thus he observed that the salts 

 which did not help the snow or ice to dissolve faster gave no efi'ective 

 freezing. He showed that water in ))ecoming ice expands hy al)Out 

 one-ninth of its volume, and bursts gun barrels. He attempted to 

 counteract the expansion and prevent freezing by completely filling a 

 strong iron ball with water before cooling, anticipating that it might 

 burst the bottle by the stupendous force of expansion, or that if it did 

 not, then the ice produced might under the circumstances be heavier 

 than water. He speculated in an ingenious way on the change of 

 water into ice. Thus he says, "'If cold be but a privation of heat 

 through the recess of that ethereal substance which agitated the little 

 eel-like particles of the water and thereby made them compose a fluid 

 body, it ma}^ easily be conceived that they should I'cmain rigid in the 

 postures in which the ethereal substance (putted them, and thei'eby 

 compose an unfluid ])ody like ice; yet how these little eels should by 

 that recess accpiire as strong an endeavor outward as if they were so 

 many little springs and expand themselves with so stupendous a force, 

 is that which does not so readily appear." The greatest degree of 

 adventitious cold Boyle was able to produce did not make air exposed 

 to its action lose a full tenth of its own volume, so that, in his own 

 words, the cold does not " weaken the spring by anything neai" so con- 

 siderable as one would expect." After making this remarkable obser- 

 vation and conmienting upon its unexpected nature, it is strange Boyle 

 did not follow it u]). He (piestions the existence of a l)ody of its own 

 nature supremely cold, by ])ai'ticipating in which all other ])odies 

 obtain that quality, although the docti'ine of a prinuun frigidiun had 

 been accepted by many sects of philosophers; for, as he saj^s, '"if a 

 body being cold signify no more than its not having its sensible parts 

 so much agitated as those of our sensorium, it suffices that the sun or 

 the lire or soiue other agent, whatever it weie, that agitated more 

 \eheniently its parts ))efore, does either now cease to agitate them or 

 agitates them but very remissh'^, so that till it be determined whether 



