78 DISSERTATION SECOND. [pabt », 



course. Earthquakes, extraordinary tempests, years of 

 great scarcity, winters of singular severity, &c. are of this 

 number. All such facts ought to be carefully collected ; 

 and there should be added an account of all monstrous 

 productions, and of every thing remarkable for its novelty 

 and its rareness. Here, however, the most severe criti- 

 cism must be applied ; every thing connected with su- 

 perstiiion is suspicious, as well as whatever relates to al- 

 chemy or magick. 



A set of facts, which belongs to this class, consists of 

 the instances in which stones have so often of late years 

 been observed to fall from the heavens. Those stones are 

 so unlike other atmospherical productions, and their origin 

 must be so different from that of other minerals, that it is 

 scarcely possible to imagine any thing more anomalous, 

 and more inconsistent with the ordinary course of our ex- 

 perience. Yet the existence of this phenomenon is so 

 well authenticated by testimony, and by the evidence 

 arising from certain physical considerations, that no doubt 

 with respect to it can be entertained, and it must therefore 

 be received, as making a part of the natural history of me- 

 teors. But as every fact, or class of facts, which is per- 

 fectly singular, must be incapable of explanation, and can 

 only be understood when its resemblance to other things 

 has been discovered, so at present we are unable to assign 

 the cause of these phenomena, and have no right to offer 

 any theory of their origin. 



VIII. Another class of facts is composed of what Ba- 

 con calls instantiae comitalus, or examples of certain 

 qualities which always accompany one another. Such are 

 flame and heat, — flame being always accompanied by heat, 

 and the same degree of heat in a given substance being al- 

 ways accompanied with flame. So also heat and expan- 

 sion, — an increase of heat being accompanied with an in- 



