384 Of the Propagation of Heat 



advanced much too far ; but it is right that I should 

 acknowledge fairly, that in the present case the temerity 

 I have shown has not been entirely without design. 



There are two ways in which philosophers, as well as 

 other men, may be excited to action, and induced to en- 

 gage zealously in the investigation of any curious sub- 

 ject of inquiry, — they may be enticed^ and they may be 

 provoked. 



It will probably not escape the penetration of my 

 reader, that I have endeavoured to use both these meth- 

 ods. I am well aware of the danger that attends the 

 latter of them ; but the passionate fondness that I feel 

 for the favourite objects of my pursuits frequently hur- 

 ries me on far beyond the bounds which prudence would 

 mark to circumscribe my adventurous excursions. 



CHAPTER IV. 



An Account of a Variety of Miscellaneous Experiments. — 

 Thermometers with cylindrical Bulbs may he used to show 

 that Liquids are Non-conductors of Heat. — Ice-cold Wa- 

 ter may be heated and made to boil standing on Ice. — 

 Remarkable Appearances attending the thawing of Ice, 

 and the melting of Tallow and of Bees-Wax., by means 

 of the radiant Heat projected downwards by a red-hot 

 Bullet. — Beautiful Crystals of Sea-Salt formed in Brine 

 standing on Mercury. — Olive- Oil soon rendered colourless 

 by Exposure to the Air standing on Brine. — An Attempt 

 to cause radiant Heat from a red-hot Iron Bullet to descend 

 in Oil. — Account of an artificial Atm,osphere in which 



