NOVUM ORGANUM. 103 



can be received and collected by the strongest and best 

 burning glasses, so as to produce even the least degree of 

 heat. But if that degree be, perhaps, so subtile and weak, 

 as not to be perceived or ascertained by the touch, we must 

 have recourse to those glasses which indicate the warm or 

 cold state of the atmosphere, and let the lunar rays fall 

 through the burning glass on the top of this thermometer, 

 and then notice if the water be depressed by the heat.* 



Sixth negative to the second affirmative. 



Let the burning glass be tried on warm objects which 

 emit no luminous rays, as heated but not ignited iron or 

 stone, or hot water, or the like ; and observe whether the 

 heat become increased and condensed, as happens with the 

 solar rays. 



Seventh negative to the second affirmative. 



Let it be tried on common flame. 



Eighth negative to the third affirmative. 



The effect of comets (if we can reckon them amongst 

 meteors) in augmenting the heat of the season, is not found 

 to be constant or clear, although droughts have generally 

 been observed to follow them. However luminous lines, 

 and pillars, and openings, and the like, appear more often 

 in winter than in summer, and especially with the most 

 intense cold but joined with drought. Lightning, and 

 coruscations, and thunder, however, rarely happen in winter, 

 and generally at the time of the greatest heats. The ap 

 pearances we term falling stars are generally supposed to 

 consist of some shining and enflamed viscous substance, 

 rather than of violently hot matter. But let this be further 

 investigated. 



Ninth negative to the fourth affirmative. 



Some coruscations emit light without burning; but are 

 never accompanied by thunder. 



Tenth negative to the fifth affirmative. 



Eructations and eruptions of flame are to be found in cold 

 climates as well as in hot, as in Iceland and Greenland ; 

 just as the trees of cold countries are sometimes inflam 

 mable and more pitchy and resinous, than in warm; as 

 the fir, pine, and the like. But the position and nature of 

 the soil, where such eruptions are wont to happen, is not 



* For the construction of Bacon s thermometer see No. 38 in the table of 

 the degrees of heat. It serves also as a barometer, but is inaccurate in both 

 capacities. 



