• Xlll. 



^bci 



w. 



2. Liibt 

 'ration of 



^ hranch 

 hing ow- 



•/. Pure 

 'dieS) anil 



hk re/pi- 



mi li^bt. 

 loHtsre- 



Counter- 



• of mat- 



of acids. 



■ompomi 



Rims 



es en the 

 itdilitj' 



I 



s 



"") 





'id. 



'I 



ti 



Cloii^ 



&ri 



Sect. XIII. 1. 1. 



ELECTRICITY. 



295 



are generally elearijed plus. Experiment on vapeur 



Rain from hydrogen and 



oxygen. 

 getation. 



Thunder fhowers, 

 Ek^ric clock. 



Ele^ric points to collet dew, and promote 



1. 1 . Philosophers are not yet agreed, whether light and heat be the 



fame fluid under difFerent modifications, or two different fluids,which 



ft frequently togeth 



The latter opinion feems to be more pro 



bable from the circumftances related below, and alfo 



from th 



logy of other aqueous, aerial, or ethereal fluids, which appear 

 fift of two other fluids combined or diffufed with each other, 

 water confifts of oxvsen and hydrogen combined together. 



Th 



At mo 



fpheric air of oxygen and nitrogen diffufed togeth 



Ele£lricity pro 



bably confifts of two fluid 



which may be termed vitreous and 



finous eleariclty. Magnctifm alfo probably confifts of two fluids 

 which conftitute northern and fouthern polarity. The power of at 



traaion feems to confift of gravitation and of chemical affinity 

 laftly, the element of fire confifts I fuppofe of light and heat. 



And 



The diffimilarity of light and heat is evinced 



th 



Ample 



mft 



mce ; that as light gives no heat to tranfparent bodies, which 

 the emanations from a fire do, there is reafon to believe them to be 

 different fluids. Thus when fmoke is blown near the focus of a large 



burninsf elafs 



b & 



does not afcend : which (h 



that th 



though it would burn or vitrify 



heated and rarlfied by it ; 



ftant any opake body, which might be oppofed 



in- 



b 



the cma 



ions of heat from a fire foon rarify and warm the air in its vicinity 

 fino- it to afcend, as may be feen by a fpiral card-vann placed ovei 



chimney-piece 



d which is agreeably feen in the ufe of th 



Mafs fire-fcreens of Parifian invention, which placed before a parlour 

 fire permit the rays of light to pafs, but intercept the emanations of 

 fluid heat. 



to 



Whence it would feem, that light do 

 opake bodies, when it falls on them 



not itfelf communicate hea 

 but combines with theni 



d 



