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through the burning-glass on the top of this thermometer, 

 and then notice if the water be depressed by the heat. 17 



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. 



Let it be tried on common flame. 



The effect of comets (if we can reckon them among 

 meteors 18 ) 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 in 

 tense cold but joined with drought. Lightning, and corus 

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



17 In this thermometer, mercury was not dilated by heat or contracted by 

 cold, as the one now in use, but a mass of air employed instead, which filled 

 tho cavity of the bulb. This being placed in an inverted position to ours, that 

 is to say, with the bulb uppermost, pressed down the liquor when the air be 

 came dilated by heat, as ours press it upward; and when the heat diminished, 

 the liqour rose to occupy the place vacated by the air, as the one now in use 

 descends. It consequently was liable to be affected by a change in the tempera 

 ture, as by the weight of air, and could afford only a rude standard of accuracy 

 in scientific investigations. This thermometer was not Bacon s own contriv 

 ance, as is commonly supposed, but that of Drebbel. Ed. 



18 La Lande is indignant that the Chaldeans should have more correct notions 

 of the nature of comets than the modern physicists, and charges Bacon with 

 entertaining the idea that they were the mere effects of vapor and heat. This 

 passage, with two others more positive, in the &quot;De Aug.&quot; (cap. xl.) and the 

 &quot;Descript. Globi Intellect.&quot; (cap. vi.) certainly afford ground for the assertion; 

 but if Bacon erred, he erred with Galileo, and with the foremost spirits of the 

 times. It is true that Pythagoras and Seneca had asserted their belief in the 

 solidity of these bodies, but the wide dominion which Aristotle .subsequently 

 exercised, threw their opinions into the shade, and made the opposite doctrine 

 everywhere paramount. Ed. 



