ADDRESS. 19 



' The production of cold is a thing very worthy of the inquisition both for 

 the use and the disclosure of causes. For heat and cold are nature's two 

 hands whereby she chiefly worketh, and heat we have in readiness in 

 respect of the tire, but for cold we must stay till it cometh or seek it in 

 deep caves or high mountains, and when all is done we cannot obtain it 

 in any great degree, for furnaces of fire are far hotter than a summer sun, 

 but vaults and hills are not much colder than a winter's frost.' The great 

 Robert Boyle was the first experimentalist who followed up Bacon's sug- 

 gestions. In 1682 Boyle read a paper to the Royal Society on 'New 

 Experiments and Observations touching Cold, or an Experimental 

 History of Cold,' published two years later in a separate work. This is 

 really a most complete history of everything known about cold up to that 

 date, but its great merit is the inclusion of numerous experiments made 

 by Boyle himself on frigorific mixtures, and the general effects of such 

 upon matter. The agency chiefly used by Boyle 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 effective freezing. He showed that water in becoming ice 

 expands by about 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 may easily 

 be conceived that they should remain rigid in the postures in which the 

 ethereal substance quitted them, and thereby compose an unfluid body like 

 ice ; yet how these little eels should by that recess acquire as strong an en- 

 deavour outwards as if they were so many little springs and expand them- 

 selves 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 near so considerable as one would expect.' After making 

 this remarkable observation and commenting upon its unexpected nature, 

 it is strange Boyle did not follow it up. He questions the existence of a 

 body of its own nature supremely cold, by participating in which all other 

 bodies obtain that quality, although the doctrine of a 'primum frigiduDi 

 had been accepted by many sects of philosophers ; for, as he says, ' 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 

 fire or some other agent, whatever it were, that agitated more vehemently 

 its parts before, does either now cease to agitate them or agitates them 



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