LIB. 11. 12. 159 



Ad quartam. 



9- Simt qusedam coruscationes, quae prgebent lumen, 

 sed non urunt: ea3 vero semper fiunt sine tonitru 5 - . 



Ad quintain. 



10. Eructationes et eruptiones flammarum inveniun- 

 tur non minus in regionibus frigidis quam calidis ; ut 

 in Islandia et Groenlandia : quemadmodum et arbores 

 per regiones frigidas niagis sunt qtiandoque inflamma- 

 biles, et magis picesc ac resinosac, quam per regiones 

 calidas ; ut fit in abiete, pinu, et reliquis : verum in 

 quali situ et natura soli hujusmodi eruptiones fieri so- 

 leant, ut possimus affirmative subjungere negativam, non 

 satis quacsitum est f)4 . 



Ad sextain. 



11. Omnis flamma perpetuo est calida magis aut 

 minus : neque omnino subjungitur negativa 5&amp;lt; \ Et ta- 

 men referunt, ignem fatuum 5(i , (queni vocant) qui etiam 

 aliquando impingitur in parietem, non multum liabere 

 caloris ; fortasse instar flammoc spiritus vini, quse cle- 

 mens ct lenis est. Sed adhuc lenior videtur ea flam- 

 ma, quae in nonnullis historiis fidis et gravibus inveni- 

 tur apparuisse circa capita et comas puerorum et virgi- 



53 Sheet lighning is supposed to disengaged. 



be only the reflection of ordinary 5(! Ignis fatuus is seen only in 



lightning. marshy and other spots where there 



54 This is clearly no Negative, are exhalations of decomposing mat- 

 For the causes and nature of sub- ter. It has been variously account- 

 terraneous fires, see Dr. Daubeny ed for by Sir I. Newton and Dr. 

 on Volcanoes. Priestly ; nothing is certainly known 



r 5 This is again an instance of about it; possibly it is caused by 



Degree. One can however imagine phosphoretted Hydrogen, kindled 



rays of light without any Heat, such either by Electricity, or by its own 



as would be the Halos which en- tendency to combustion in air. The 



circle holy heads in Paintings. The flame of Spirits of Wine, instead of 



flames of different substances have being &quot; clemens et lenis,&quot; is one of 



different degrees of Heat, arising the most intensely hot kinds of 



from the different amounts of gases flame. 



